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Mythranil

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Posts posted by Mythranil

  1. How would it be possible to test for this disease accurately with fossils? I agree another ridiculous creationist claim.

     

    I would think that it would be a simple matter of comparing skull structures to those found in modern victims. While all the skulls would be different, they would still have some features in common. I guess the key indicator would be that an otherwise normally developed fossilized skeleton would have a skull with various stages of development. I would also think that the deformation would cause characteristic microscopic changes in the skull's growth patterns as well - ie, stretched or elongated (overall, stressed) bone tissues and cavities, etc. The fossilization process should preserve some of this structural evidence.

  2. Sweet I want one! I'm guessing they don't tend to show up on the seashore though...

     

    Not that I've seen - like I said, it's usually only in shale deposits, and those can be found all over the place... I have several in my possession I collected from a shale deposit on the side of a mountain at 10,000 feet. A lot of the time the fossils in shale ended up there after dying and settling all the way down to the ocean floor, but the ones that seem to secrete the pyrite actually lived on the ocean floor itself. Unfortunately I have them all in storage right now... 1,800 miles away... But when I have them back in my possession I'll take pictures and post them to this thread.

     

    Have a good weekend!

  3. But that's not really a *goal*, that's just similar selection pressures. A goal, in the sense it's often used, is something beyond these pressures, some direction that cannot be explained simply by adaptation to local environmental conditions.

     

    I couldn't agree more; Simon Conway Morris seems to think there truly is an end goal - or maybe I misunderstood his point on the matter - but I have a hard time believing that. I don't see why there would be any reason for an evolutionary goal. What could possibly be a controlling factor on that? We'd have to start considering things like Creationism, perhaps... And that's a whole other ball of wax.

     

    In another thread I commented on the fact that whales were originally land-based mammals. If evolution had an end goal in mind, why take a detour and bring life out of the sea, evolve lungs and legs, then send them back to the sea again? Cut out the middle man... Unless it's some huge evolutionary advantage to have lungs in the ocean. Does anyone know if it's more efficient to breathe oxygen from the air than from water..? Maybe that's why, in part, they can grow to such sizes.

     

    But even so, is that really a necessity for evolution? Isn't it more efficient to keep a smaller body size so you need less food resources?

  4. Some of the best depositional environments - especially where shales are concerned - occur deep underwater where there can be increased concentrations of metals in the water column. Pyrite forms frequently in shales. Not sure what type of rock your formation is made up of, but that'd be my guess. Part of the reason behind the high concentration of metals is due to the presence of deep-sea vents - the metals seep into the water from vertical hydrothermal fluid movements.

     

    On a related note, there are some fossils made out of pyrite that did not form from the process of fossilization. Some shelled creatures are chemotrophs that feed off of the same deep-sea vents, and in the process, they absorb a lot of the metals present in their food supply (on an unrelated note, as a palaeontologist I have at times used the metallic isotope 'fingerprint', if you will, to identify where an organism spent its life). In any case, certain bivalves, gastropods, and molluscs secrete their shells directly out of their skin using whatever extra components they pull out of the seawater, and this is usually calcium, but you can get some weird forms like pyritized shells too. They look really cool =)

  5. Pretty sure this is an ammonite - there's a specific shell morphology (can't recall the term) that is almost columnar in appearance; my guess is that you're looking at one that was split open along the long axis before becoming fossilized.

     

    I've hunted down a picture of the type of ammonite I had in mind - what are your impressions based on this?

    ammonite.jpg

  6. Why do you think the US needs the water as badly as you imply? The US has great reserves of water as well, bordering with Canada most of the great lakes (with the exception of Lake Michigan which it completely within the border of the USA). And should water truely become scarce in parts of the USA, we can adapt our usage as an alternative to importing water. We are growing vast quantities of water-intensive rice and cotton in the deserts of the US southwest, certainly we could reduce water consumption by growing less water intensive crops there if really needed.

     

    This is all an issue that hits close to home for me, in several ways:

    1) I am a Canadian;

    2) My home province (Saskatchewan) has more reserves of clean, fresh water than anywhere else in Canada;

    3) I am currently living in Southern California;

    4) I work in an industry related to water resources;

    5) I work in the desert. A lot.

     

    Hopefully those are good qualifications to give a somewhat informed opinion from.

     

    In any case: the area I live in is, on average, middle- to upper-class by all of your definitions. I don't think that anyone here uses water any more than the average person. There are some upper-class communities that I know use more than the average family, just as I know there are some lower-class communities that use a lot more water on average as well. Regardless of this, we have reports in our news and papers daily on what our current water supply is, and I have personally heard and seen many broadcasts on TV and radio asking citizens to make an extra effort to conserve water for a specific duration of time.

     

    But with regards to the Southwest USA it seems to make more sense to me to do a better job conserving the water they already have than go to these extremes to get more water.

     

    The problem is that our existing water reserves are full of contaminants from fuel, solvents, pharmaceuticals, and general trash. It requires A LOT of energy, resources, and time to properly return water to a potable state. We're talking about amounts of money comparable to the state budget. That being the case, it gets put on the back burner for the most part because it's just too expensive to repair the problem. The source of money to clean up our water reserves - here specifically known as the State Fund - receives its revenue from 3% of fuel cost. I am in the industry of environmental consultants who work at cleaning up our water resources (specifically, we clean up the carcinogenic contaminants), and the largest projects out there are reimbursed by the State Fund. With our current economic recession, the state's governor has decided to withdraw all money from the State Fund and put it towards other projects - like repaving our freeways once a year (this blows my mind, but that's a whole other discussion). We have been issued IOUs for all the work we've done, and now our clients won't allow us to move forward on any projects until everyone gets reimbursed by the nonexistent State Fund again. Thankfully, we only ever had about 5% of our projects reimbursed by the State Fund, but some of our associates relied entirely on those projects and have since declared bankruptcy.

     

    Bottom line - our water resources in the Southwest are toxic to drink. Desalinization plants are energy-intensive and inefficient, and with the vast number of people living in the Southwest, we already have problems supplying enough energy. We regularly experience 'rolling blackouts' and 'brownouts' when too many people kick on their air conditioners.

     

    I don't think that you can easily start exporting large amounts of water from Canadian lakes and rivers without having a large impact on the ecology. Perhaps you can remove water from rivers that have nearly arrived at the sea? I would be very cautious to remove water from an area that is all natural (without artificially maintained water levels).

     

    I've read somewhere in the past decade - and don't quote me on this, my memory is sketchy about it - that large volumes of water are already being piped down into the western USA from British Columbia and Alberta into Washington and Oregon. A lot of the places in Canada where there are fresh water reserves are wetland environments and span very large areas; to disturb those niches would be disastrous from an ecological standpoint. Most water reserves are already zoned in National Parks so they are protected for that very reason.

     

    I don't see a real problem with agriculture, but I object to using this precious water for rice and cotton rather than crops which require less water when water is in short supply. With Industry, why should the industries requiring lots of water be built in a desert?

     

    The desert is a finicky place, and not many plants can grow there, water or not. There are other factors to consider, especially soil constituents. The desert is composed largely of silica-based sands (ie, quartz, micas and feldspars), and plants that grow there need to be able to incorporate silica into their structures. The grass family relies very heavily on silica for its structural component, and a prominent member of that family is rice. I'm not familiar with any areas in the southwest that grow cotton, though...

     

    As far as industries go - it's been my experience that most industries require large volumes of water to operate. I'm sure there are many exceptions. Part of the history of desert-based industry is that, following World War II, there were a lot of people looking for work and the country was in a place where it could expand aggressively. Moreover, the military had discovered several chemical-based lubricants that worked far better to cool down equipment than plain old water, and thus industry was built in the desert because it was cheaper land and you didn't have to rely on water for cooling processes anymore. Then, in the 1980s and 1990s, it was found that two of these chemical lubricants (tetrachloroethylene and hexavalent chromium) were causing severe environmental problems and were highly carcinogenic (and hexavalent chromium was also mutagenic). All of a sudden, desert-based industry had to switch back to water for its processes, and a water reserve deficiency developed.

     

    It may be there regional differences. I've always lived in parts of the country that generally get quite a bit of rain. The grass does not usually need watering to stay green, so when dry spells arrive, most people don't bother watering. During these times, the grass might go brown, but it will turn green again when the rain returns in a few weeks. I sense some irony in that people living in wet areas of the country are more frugal with water than those living in dry areas...

     

    Perhaps the people living in areas with more precipitation simply don't need as much water to live the same lifestyle as those in arid areas. I agree though, people invest too much in keeping their grass green. It looks great, but we should really conserve more. Here in the southwest, we don't get much rain at all in a year; last year, it rained intermittently for one week in February and that was it.

     

    Just so you have a point of reference, I live in Austin, TX. I was ecstatic yesterday when it rained for 5 whole minutes... First time since June... But, 5 minutes isn't squat, and it evaporated in just as short a time in the 103 degree heat.

     

    Oh, so you live in the cooler climate of the American south, I see... :)

    Like I said, I live in southern California and work a lot in Arizona and Nevada, and some of my worksites regularly exceed 130 degrees Fahrenheit, no joke. Thankfully, the humidity level is very low, so... It's a dry heat!

     

    The bigger question is: why are people living in the desert. Without those people, it is likely that the industry wouldn't be there either.

     

    I can't answer for all the 'desert rats', as they call themselves... Part of it comes from American history, another part comes from global trends. There are settlements of people all up and down the Colorado River in Arizona/California that live in 100 + weather all year long. A lot of them are native tribes that have lived there for centuries, if not millennia, and originally settled there to keep close to the river. There is vast archaeological evidence of expansive irrigation having been dug in the desert floors - check out the Topock Maze if you're interested, it's a geoglyph you can see from satellite photos - but that was also back when the Colorado River was 10 times the size it is now. With large constructs like Hoover and Davis Dams upriver, the volume of water in the Colorado has greatly diminished. The size of the floodplains are unbelievably huge. The water levels would have to raise by, perhaps, 20 feet to spread out to its previous size.

     

    The earth is also experiencing a warming pattern - whether you attribute it to the man-made greenhouse effect or from global cycles, regardless, it's happening. Back when the native tribes settled the land, the climate was much more temperate.

     

    Many of the other people living in the desert communities enjoy the wilderness, the cheap cost of living, and the ability to actually have a sizeable yard. Believe me, with house costs being what they are here now, I considered moving to the desert and commuting an hour or two in to work... For a moment. I don't care for the heat, myself.

     

    It's paradoxical now. The industry gives the people jobs, and the industry pollutes the water and kills them off. It's like a microcosm with it's own built-in population control. One thing you'll notice is that there is no population gain or loss in desert communities.

     

    My feeling on the matter is that we need to find a more efficient way to harvest ocean water and make it potable. We also need to invest much more money into cleaning up our existing water reserves, but I'll tell you this - after what I've seen working in this industry, it's going to take many decades of work to clean them up again. There's a LOT of contamination out there.

     

    Bottom line: don't drink the groundwater.

  7. While not necessarily related to research funding, my own industry (environmental consulting) is experiencing funding-related issues. Some of our work (thankfully, not more than about 5%) is reimbursed through the California State Fund. The way it works is that 3 cents out of every dollar of fuel gets deposited into the aforementioned Fund, and consultants like myself work to clean up fuel and other chemical spills (all carcinogen-based) utilizing technology and are reimbursed through the Fund. Well, our governor has been having some money management problems and realized there was a large stash of cash in the State Fund; he ended up borrowing the Fund money and sent out IOUs to our industry that we don't have much hope of cashing in, especially when our state is on the verge of bankruptcy.

     

    Now, they're talking about increasing the fuel tax to bring new revenue into the State Fund, but what's to say it's not just going to be a deeper pocket for the government to collect from? Meanwhile, we have to let our projects rest, and the contaminant plumes are free to roam. In an area like Los Angeles, these people are having major health problems, some of which stems from these carcinogens. There's definitely a human price to pay for this irresponsibility, not to mention the toll on the rest of the biota. It's a sad sign of the times.

  8. This is somewhat unrelated perhaps, but I think it was a missing link of sorts for that specific area. Interesting stuff, none-the-less. Check out the Washington Post article:

     

    http://www.washingtonpost.com/wp-dyn/articles/A2141-2004Oct27.html

     

    Also, look for information on a creature called Pikaia gracilens, the 'missing link' for the beginning of the chordate history (ie, the creature that gave rise to backbones). It's part of the Burgess Shale deposits, something I worked extensively on in the past.

     

    Hope that helps.

  9. I always viewed a species as having a unique set of genetic possibilities that allows variation in traits, but not entirely new traits. For example, a whale can vary in size and color, but it cannot spout legs.

     

    It's besides the point, but whales actually descended from land-based creatures of the ungulate family (that family also gave rise to most of the modern-day hooved mammals). Whales still have some vestigial anatomical features hinting at their quadrupedal history. So - as I said, it's still besides the point, but should the whale's environment become unlivable for whatever reason, they may end up sprouting legs once more and return to land.

  10.  

    Evolution is NOT a directed activity. There is NO universal scale that measures how better all things are in relation to all other organisms.

     

     

    I would argue that evolution does have direction, in a sense, that is an effect of our environments. It's been shown that organisms evolving continents apart but living in the same or similar environmental niches will display convergent evolution wherein they evolve similar physical traits; there are many examples of this, but perhaps the best modern-day examples stem from the Australian marsupials, most of which have counterparts on other continents, yet they have not possessed a common ancestor for a very long geological timeframe. There's also the evolutionary convergence of monkeys in South America and some of the apes and monkeys in the old world.

     

    Simon Conway Norris is a proponent of this mode of thought; he goes further to suggest that evolution is, in a way, directed and driven by our environmental niches with an endgoal in mind, if you will. We're all evolving to develop traits that help us adapt to our environment, and the only reason we haven't stopped evolving is because our environments continually undergo change. He also claims that intelligence and consciousness are an endgoal of any evolutionary niche, and this is because it is the ultimate tool of choice in terms of adaptation. I'm not sure if I support the last idea of his or not, but I thought I'd throw that out there anyway.

     

    I'm sure there are plenty of other examples of convergent evolution out there today; I'm not as familiar with modern life forms as I am with past life forms.

     

    On a somewhat related note, given that premise, do you suppose that humans are artificially altering the genetic constituency of populations based solely on the idea that we are causing climate change (and that too, of course, is still open for debate as well)? I don't think there's a straight and narrow path for evolution, by any means, but by changing the environmental niches on the planet, we have evolution move in a different direction than it would have if humans or their hominid ancestors didn't make the scene.

     

    If our effect on global climate change is as drastic as some would claim, and we end up increasing global sea levels and cause land masses to dry up and turn to desert (a la Triassic period), do we cause all life in the seas to generally converge to one endpoint, and terrestrial creatures to another? Of course, these global climate changes would have to be extreme and semi-permanent for something of this magnitude to happen; but hypothetically, what if we did reduce our effective number of ecological niches to just these two? (I understand there are sub-environments, ie, coastal, brackish, delta, etc.; let's forget about those for the sake of the concept).

  11. I, too, experience frequent (if not nightly) lucid dreams; as Moontanman describes, I am in control of the dream but they do have a direction of their own. In the end, I am only able to influence my own actions and perceptions of the dream itself. I also find that my lucid dreams tend to be founded solidly in the basis of reality - usually not my own, and usually not in this timeline - but there are no unusual physics involved, no odd things floating in the skies, no superpowers, and strangely, no sexuality, just like you said too. Another effect is that I typically wake up feeling exhausted afterwards, and I especially feel like the muscles I used in vigorous dreams are sore when I wake up, just like I've actually used them. My wife tells me that I talk a lot in my sleep too.

     

    I'm sure the question has been raised before - but is it possible that dreams in some way can subconsciously access recessed or genetic memory? My most lucid dreams are always in settings in the past. I often awake from those to wonder which is the dreamworld and which is reality...

  12. My point of view is that a human born on the moon and subjected to different gravitational strains would still be a human. A single generation of genetic change is, of course, simply not enough to qualify that answer on. You would need to go back to our beginnings, wherever that may be, and place those identical ancestors on the moon and see if they evolve into humans or take another path. My guess is that they would turn out to be something different, just as all life on earth became something different depending on their environmental strains. Perhaps the question you are getting at is: would humans, or a similar species (in mental capacity, at least) evolve under any condition? And the follow-up question that's been posed before: are humans a necessary step in evolution's designs? And furthermore, does intelligence always evolve, and if so, would it be in bipedal creatures with society and culture?

     

    I'll say this much, that I hope we can all agree on: if life evolved on the moon starting at the same time it did on earth, it would invariably be different morphologically and would have different thought patterns. My guess is that, in a harsher environment like the moon (this is all so highly hypothetical, of course), the development of instinct would be greater than the development of consciousness.

     

    As far as the Eskimo and the Philipino: they have already developed some small genetic differences to adapt to their environments; Eskimoes have developed (or retained?) larger nasal passages to more effectively process the cold air they breathe; Philipinos have developed coarser hair that does not mat down as much as other humans to aid in the dispersion of heat. But moreover: does this mean that their brain chemistry has changed? Not much. We're all still human and have the same base needs and desires. With time, perhaps there would be some change.

  13. Stephen Jay Gould and Niles Eldredge spoke extensively about their theories on punctuated equilibrium and phyletic gradualism (layman's terms: genetic leaps vs. watching the genetic paint dry). I think their viewpoint holds some merit where sudden, single-generation changes in geography or environment are concerned; to thrust a species from one extreme into another would cause drastic changes in selective pressures and quickly change the dominant phenotypes. With populations that lived under relatively static conditions, a leap in genetic mutations would not necessarily be beneficial, especially if the dominant phenotypes were already living comfortably in their environment. Competition between the species in this case would not be as important.

     

    We must consider under what conditions such a drastic environmental change could occur, and what clades it could have affected. It would need to be something geologically instantaneous - a sudden change in food supply, breathable oxygen content, meteorological disturbances... Who knows. A colleague of mine (passed on now, sadly) always held the theory that the dinosaurs gave way to the mammals not directly because of the infamous comet, but because of the side-effects - a potential reduction in global oxygen supply, the nearly coincident rise of angiosperms and subsidence of gymnosperms. His feeling was that the dinosaurs simply were not able to digest the angiosperms and phased out when flowers gained dominance.

     

    As for the subject question (does evolution have stages?), I don't see how evolution could progress in stages because there are small variations in every individual, to some extent. We are always changing. We'd need to be in a completely static and unchanging environment with a similarly static control on populations. It's the same reason that identical twins still grow up to be different people. We all experience different things and grow and change accordingly. I think this holds true on the genetic level, as well.

     

    One of Gould and Eldredge's arguments for punctuated equilibrium was that the fossil record did not reflect gradual changes in morphology. This always blew my mind, because I've always seen just the opposite. I did my time with trilobites early in university and the genetic diversity from one age to the next is amazing. Without these morphological variances, in fact, we would not be able to correlate in the geological record (relative time, that is); a lot of geological formation correlations rely on subtle changes in trilobite, brachiopod, and foraminifera morphology, amongst many others. I think they really missed the dartboard on that one.

     

    My overall problem with this - and some of the other debate topics - is that the questions are posed (presumably) for a black-and-white answer. I don't think the answer to many of our threads are that simple; to me, it seems likely that both methods of evolution played an important role.

  14. they aren't vital to human survival but can be quite important. they'll reboot your intestinal bacteria should you encounter a 'clear out' so to speak. be it intentional(laxatives) or diarrhea from an infection.

     

    I'd also heard that the aforementioned bacteria will actually pull back and 'hide' in the appendix during such a disturbance.

  15. Do you recall which journal this was in? Or was it at the SVP meeting last week?

     

    First of all, my apologies - I am not able to find the abstract just yet. When I put more thought into it, I realized that the seminar I heard these findings from was the North American Paleontological Convention back in 2001; I guess it was still recent on a geological time scale though...

     

    What I recall from the lecture was that it was not the primary focus. As paleontologists tend to do, he became sidetracked and was discussing some unrelated yet, to him at the time, interesting findings and conclusions. I believe it was originally a lecture about synapsid morphology - specifically, whether Dimetrodon and Edaphosaur sails were cartilage-based or fleshy (as I recall, there was some mounting evidence of them actually being flesh-based sails).

     

    I'll keep an eye out for the materials I brought back from the conference and see if I can dig up the presenter's name and abstract.

  16. This may be of interest regarding the conversation - some of the new findings in palaeontological research suggests that while the ornithischian dinosaurs were cold-blooded, that saurischian dinosaurs probably evolved to have warm blood. This was evidenced by bone fracture healing patterns. If I understood it right, bone heals in a different pattern depending on the bacteria living in the blood, and some bacteria require higher or lower temperatures to exist in the bloodstream. Several fractures in T. rex bones have shown healing patterns that indicate they must have been warm-blooded.

     

    It makes sense, IMO. The more we find out about some of the later saurischians, the more it seems like they have warm-blooded tendencies. In the news a lot lately are fossilized feathers on such creatures.

  17. I read through it some time ago and, as others have stated, found it interesting in a historical context. It's a great primer for university students in the sciences because I think it follows a natural and logical procession. Whatever we can do to enhance our logic and reasoning skills is worthy of attention. Plus, it's just a great example of primary science - thinking for yourself, and thinking outside of the box. Today, in my opinion, we need to spend so much time doing research that we neglect coming up with new ideas. It's like the science fair thing - remember when student ideas were original, primary works, before there was so much information to absorb about our environment? Now, I see a lot of kids churning out research projects at science fairs - ie, "How DNA is Structured", or "How Lasers Work!" kind of things. Of course, that's all a function of our educational system, too.

  18. Best thing to do may be to ask for the source of his information. I'm sure that, if you compared modern craniums affected by Pfeiffer Syndrome, they vary greatly in average shape; it seems improbably that the disease would cause all the craniums of H. erectus to take the same exact shape.

     

    Not that I want to spur a debate on eugenics between you and your associate, but how would he explain the variation in skull shape between the cultures in modern-day earth? They do not all vary in size and shape due to one illness or another.

  19. Sadly, even with lizards, indeterminate growth has a limit too. As we see with most cases of land-based gigantism, the physical constitution of our skeletal structure and cardiovascular system cannot sustain the strain of that much weight under the effects of our gravity. Godzilla could not exist because he'd have lung and/or heart failure even before the Japanese shoot him down. Now, with water-based creatures, it's a whole other matter - it seems odd that gigantism hasn't occurred more frequently in the oceans than it has.

     

    On a side note, I've often wondered if the cause for the dinosaur gigantism was a shift in the natural gravity field of the earth. Don't know what would cause this, and I never bothered to look into it, but it had been a thought.

     

    It seems that examples of human gigantism meet a similar fate as our Godzilla. At some height of roughly 9 feet, our systems - in their current configuration - cannot take the strain.

     

    I think that, if human evolution (outside of height) ceased, our average height would plateau, assuming our food supply and environmental conditions also cessated change. Both situations are improbable and, more likely, impossible. If it's a greater advantage for humans to be taller, we will first have to evolve our body plans and cardiovascular systems to be able to sustain our increased size. Note, too, that the human brain can only control so many facets of the overall human body; nerve functions require a lot of processing power. Our brain size may have to increase before our body size can increase as well.

     

    As for human growth trends - I think humans have artifically altered our evolution by creating stable food sources. In the Americas for example, a constant supply from the same food sources seems (in my opinion) to have caused our younger population to grow taller and more robust. I went to school in a rural community where the average height of the population was, say, 5' 8" in men; later on, in high school, we were mixed in with the taller populations from the city who averaged closer to 5' 10". Now, when I go to my kids' high school, it seems like the average height of males is much closer to 6' 0". I don't see how natural evolution, punctuated or not, could produce that much of a height differential within two or three generations. To me, that's clearly a product of societal changes with regards to our food supply.

     

    I think I got sidetracked, but hopefully addressed some of the topic...

  20. My knowledge on this area is slim at best. My question is - how similar are the tools of these species between continents or regions? Is there the possibility that these particular tools are formed in a logical succession - that is, that the development of the axe was likely to happen within a species because of environmental needs and/or psychological adaptations? From an evolutionary perspective, we see examples of this repeatedly - called "convergent evolution" - where separate and sometimes completely unrelated species or groups evolve very similar body plans in response to their environments. Could it be that these early hominids, at some point, were predisposed to invent these technologies?

     

    On another related note - how similar are the materials being used between different groups? You could support an argument for the trade of technologies if you find that the materials being used are not common in all areas. I would think that early tools would primarily be made out of necessity and with the most convenient resources at hand. If tools a continent apart show a clear geographic path using the same materials, and some of the groups live in areas without that particular resource, there's your evidence of physical trade. If it's a specific technique, like a specific form of flint knapping that is contrary to natural cleavage of the rock, that would seem to be more culturally driven and is most likely societal trade.

     

    Any additional thoughts on your part..?

  21. I was in a field camp in central Montana where there were three separate geological columns within 20 square miles that represented the entire geological history of that area (although this included gaps from erosional periods, too). The blocks were Precambrian, Cambrian through Triassic, and Jurassic through Quaternary.

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