# Is it utterly impossible...\[civilization existed on Earth 100 million years ago?\] **URL:** \ **Category:** In My Humble Opinion\ **Created:** [May 15, 2014, 11:04pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558 "2014-05-15T23:04:35Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [May 16, 2014, 2:36pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/21 "2014-05-16T14:36:55Z")
> [@YogSosoth](#): > > But suppose the civilization from that time doesn’t value copper or gold. They could have mined all of the existing iridium and that’s why we don’t have any now, couldn’t they? They might ignore gold but copper is far to useful. Besides Iridium melts at 2447C, Iron at 1538C and Copper at 1085C. Ancient Greek food fired pottery kilns typically reached ~900 C so no one is jumping from stone axe heads to iridium ones unless they go through copper and iron first. ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [May 16, 2014, 2:57pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/22 "2014-05-16T14:57:19Z")
Any “civilization” is likely to at the least use stone and bone tools. There is no reason whatsoever for these to all disappear without trace - after all, we have bones surviving just fine in the fossil record from 100 million years ago. Now, give this civilization pottery, and its traces become ubiquitous. There are whole hills in the ME (“tels”) made out big mounds of broken pottery. There is no reason why some bits of broken pottery would not survive 100 million years in the fossil record. That’s for a neolithic-level civilization. One like ours would leave even more significant traces you could possibly see millions of years into the future. To give but one example, we have cut perfectly straight road and rail-ways through the Canadian shield - a rock formation that in some places is over a billion years old. There is no reason why some traces of these would not remain visible, even after a lot of glaciation. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [May 16, 2014, 3:12pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/23 "2014-05-16T15:12:54Z")
> [@TonySinclair](#): > > If they were truly intelligent and used biodegradable materials for all their construction, sure. Maybe we should try that. No shortage of jobs when you have to rebuild the roads and bridges every six months. How about the Naavi in Avatar? I thought the argument against this hypothesis was that intelligent life took \ to evolve? Thus it was impossible to have intelligent life \ years ago. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 16, 2014, 3:45pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/24 "2014-05-16T15:45:31Z")
> [@nevadaexile](#): > > 100 million years ago areas which are now underwater could have been surface landmasses. Assuming a small civilization (\>10 million people or whatever) clustered relatively close together in an area which is now underneath one of the world’s oceans, there would be almost no way that scientists could tell if such a race existed or not. Naah. Do you know when the human population first reached _one_ million people, never mind ten? 10,000 BCE. 5,000 BCE for the 5 million mark. Do you know how widespread humans were by that time? How many traces we’d left on the planet? We were building pyramids before there were ten million of us, and we were [everywhere](http://en.wikipedia.org/wiki/File:Spreading_homo_sapiens.svg) except Polynesia, Madagascar and Greenland. > [@](#): > > Or such a race ould have developed in an area where there has been extensive volcanic activity (such as the Siberian or the Deccan Traps) and the remains of such a civilization could be buried underneath. Going by our own experience, a civilization doesn’t just happen in one place. No flood basalt could cover even just the pre-Out-of-Africa part of _our_ record, which stretches from [Olduvai](http://en.wikipedia.org/wiki/Olduvai_Gorge) to [Blombos](http://en.wikipedia.org/wiki/Blombos_Cave#Pigments_and_engraved_pieces_of_ochre). Never mind the pre-_sapiens_ hominids who made it all the way to Asia. That’s not going to go in one, or even several, flood basalts. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 16, 2014, 3:49pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/25 "2014-05-16T15:49:42Z")
> [@AaronX](#): > > I thought the argument against this hypothesis was that intelligent life took \ to evolve? Thus it was impossible to have intelligent life \ years ago. I’ve never heard this argument, and it’s a bullshit one, because mass extinctions reset that clock on an unpredictable calendar. Who knows what the dinosaurs might have led to, absent Chicxulub. ---
**Author:** ![nevadaexile](https://avatars.discourse-cdn.com/v4/letter/n/eb8c5e/32.png) [@nevadaexile](https://boards.straightdope.com/u/nevadaexile)\ **Post date:** [May 16, 2014, 3:51pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/26 "2014-05-16T15:51:23Z")
> [@MrDibble](#): > > Naah. Do you know when the human population first reached _one_ million people, never mind ten? 10,000 BCE. 5,000 BCE for the 5 million mark. Do you know how widespread humans were by that time? How many traces we’d left on the planet? We were building pyramids before there were ten million of us, and we were [everywhere](http://en.wikipedia.org/wiki/File:Spreading_homo_sapiens.svg) except Polynesia, Madagascar and Greenland. > Going by our own experience, a civilization doesn’t just happen in one place. No flood basalt could cover even just the pre-Out-of-Africa part of _our_ record, which stretches from [Olduvai](http://en.wikipedia.org/wiki/Olduvai_Gorge) to [Blombos](http://en.wikipedia.org/wiki/Blombos_Cave#Pigments_and_engraved_pieces_of_ochre). Never mind the pre-_sapiens_ hominids who made it all the way to Asia. That’s not going to go in one, or even several, flood basalts. It seems that you are presupposing a HUMAN intelligent race. I didn’t. Also, after the passage of so many millions of years there’s simply no telling what would remain of a civilization or where anyone should or would begin to search for it. ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [May 16, 2014, 3:57pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/27 "2014-05-16T15:57:50Z")
> [@nevadaexile](#): > > It seems that you are presupposing a HUMAN intelligent race. > I didn’t. > Also, after the passage of so many millions of years there’s simply no telling what would remain of a civilization or where anyone should or would begin to search for it. For a “civilization” to not leave observable traces, that is observable over 100 million years later, it would have to be quite unlike any “civilization” we know about. From what we know, intelligent life (let alone ‘civilization’) tends to spread out as far as it can - leaving all sorts of traces all over the place in the form of un-degradable stone tools, which ought to last essentially forever (or at least until the next subduction). It is possible other life forms would not follow that pattern, but it seems to me unlikely. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 16, 2014, 4:08pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/28 "2014-05-16T16:08:59Z")
> [@nevadaexile](#): > > It seems that you are presupposing a HUMAN intelligent race. No. just one with a recognizeable-to-us path to ‘civilization’ i.e slow acquisition of tool use, social cohesion, hunter-gathering, transitioning to agriculture, first cities. Which, given that we’re explicitly talking about Earth’s history, is a good first premise. Any postulation of, say, intelligent jellyfish etc can wait for a SciFi thread. I thought this one was more serious than that. If there was going to be a civilization 100 Ma, it would be a dinosaur one. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [May 16, 2014, 4:15pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/29 "2014-05-16T16:15:59Z")
A theme expressed in a sci-fi book (I forget which one) stated that a planet has 1 opportunity to have a civilization of intelligent life become ‘spaceborne’. The reasoning is that a civilization will need to consume all easily obtainable resources to advance to that point, and once they are gone advancement to intersteller space travel is no longer possible. It also stated that if that intelligent life was aquatic that would be a dead end also. ---
**Author:** ![Shodan](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@Shodan](https://boards.straightdope.com/u/Shodan)\ **Post date:** [May 16, 2014, 5:04pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/30 "2014-05-16T17:04:38Z")
> [@kanicbird](#): > > It also stated that if that intelligent life was aquatic that would be a dead end also. I suspect an aquatic civilization would be, not so much a dead end, as a non-starter. An underwater species would not be able to develop a technological culture, because lighting fires is not possible under water. And fire is the easiest way to release chemical energy that is portable and reproducible. I think that if we ever contact or find evidence of another civilization, that civilization will have [ul][li]Fire[/li][li]Organs of manipulation analogous to hands [/li][li]Some kind of flexible, symbolic communication system that does not tie up the hands, so they could communicate while working/hunting/whatever[/li][li]Agriculture[/ul][/li]These are IMO the _sine qua non_ of any technological civilization. Regards, Shodan ---
**Author:** ![TonySinclair](https://avatars.discourse-cdn.com/v4/letter/t/49beb7/32.png) [@TonySinclair](https://boards.straightdope.com/u/TonySinclair)\ **Post date:** [May 16, 2014, 5:07pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/31 "2014-05-16T17:07:13Z")
> [@MrDibble](#): > > We dig \*below \*thick layers of lava all the time. Not 6,000 feet thick, which is the average depth of the lava forming the Columbia Plateau, the example I mentioned. Maybe we could drill a hole through that, or even a mine shaft, and certainly some portions of it might wear away through natural processes over millions of years. But if it covers tens of thousands of square miles (as it in fact does), it would be very easy for a city of a few square miles to remain hidden indefinitely, even if the buildings are made of wood or brick. It seems that most of the posts here are answering a different question than the OP poses. It’s not asking if it’s likely, and it’s not assuming a worldwide civilization. It’s asking if it’s _utterly impossible_ that we wouldn’t have found evidence of a civilization, which might have been confined to a small area. And I haven’t seen anything yet to make me believe it’s impossible. The definition of “civilization” is also problematic, because from everything we know, it IS utterly impossible that there were humans 100 million years ago, so we can only be talking about a non-human civilization, and all the common definitions are for humans. Someone above said it’s just living in cities, but if that’s true, we have to have a very flexible definition of “city” that accepts a non-human premise, and probably one that would include beehives, anthills, or termite mounds. More technical definitions I’ve found stress stratification into social classes, but that would disqualify an ideal democracy. Another try at a universal requirement is literacy, but now I’m thinking of the treecats of the Honorverse (a sci-fi series of novels and stories). They are telepaths, and have “memory singers” who are walking archives, so they have no need of a written language. Again, once you agree that we’re not talking about human civilization, we’re sort of winging it. IMO the most reasonable interpretation of a non-human civilization is an organized society where the members work together for the common good, and live in a fixed location. And I still don’t see how to disqualify social insects from that definition. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [May 16, 2014, 5:38pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/32 "2014-05-16T17:38:25Z")
> [@MrDibble](#): > > I’ve never heard this argument, and it’s a bullshit one, because mass extinctions reset that clock on an unpredictable calendar. Who knows what the dinosaurs might have led to, absent Chicxulub. Don’t people looking for intelligent life say one of the conditions is a star with stable output for a long enough time, with no major changes/extinctions? ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [May 16, 2014, 5:54pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/33 "2014-05-16T17:54:04Z")
It’s certainly possible that there were species with brains as large and complex as ours, that had some sort of communication and social system, that we could recognize as “intelligent”. Proboscideans and Cetaceans are living examples of creatures of this sort. But we’ve never dug up a dinosaur fossil with a brain anything like what mammals have. I know the old “brain the size of a walnut” thing is false, but the fact is that dinosaurs–even the theropods–had really really small brains. Yes there could have been exceptions, but we’ve never found one with a brain that would compare with a cat or dog or squirrel, much less a monkey or elephant or dolphin. Yes, creatures with small brains can have pretty complex behaviors and do amazing things. But these creatures are the opposite of intelligent, instead they have incredibly stereotyped behaviors and are unable to learn much of anything. Instead they react to stimuli in a very inhuman way. Put a chicken’s head under its wing and it just falls asleep. Boom. So, if there was an intelligent species of dinosaur, it would have to evolve from smaller-brain species. Human beings have really large brains compared to apes, and early hominids were really rare, but ape and monkey fossils are dead common. To have a rare brainy dinosaur species you’d expect to see lots of less-brainy closely related species, the same way we find monkey and ape fossils everywhere even though hominid fossils are rare. And we don’t see anything like this in the fossil record. Is it possible that these fossils are there and we just haven’t found them? Like, the intelligent dinos were all on the [Kerguelen Plateau](http://en.wikipedia.org/wiki/Kerguelen_Plateau), which is now underwater? Yes, there were micro-continents like this in the past that are now mostly underwater or subducted. But of course, this means that the brainy dinos were a rare group. They never spread out over the world, never migrated to another continent. Which argues that, brainy as these dinosaurs might have been, they didn’t have civilization or technology or social organization anything like what early hominids had. This means not just no “civilization”, but nothing even at the level of the toolkit of _Homo erectus_. If we want to imagine intelligent species in the Mesozoic, it’s much more likely they were ammonites than dinosaurs. There were lots of really large species of ammonites, some larger than 2 meters. And while we don’t have fossils of them, it’s pretty likely that there were all sorts of unshelled cephalopods that didn’t preserve very well. These guys could have had human sized brains, as well as manipulative tentacles that could do anything the human hand can do and more. The only problem is that they lived in the ocean, so their civilization if any would have been very different than human ones since humans have used fire since before we were human. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 16, 2014, 6:20pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/34 "2014-05-16T18:20:30Z")
> [@TonySinclair](#): > > Not 6,000 feet thick, which is the average depth of the lava forming the Columbia Plateau, the example I mentioned. Sorry. My views are prejudiced by having worked in a mineshaft below just such a flood lava…not near as thick now, though. > [@](#): > > Maybe we could drill a hole through that, or even a mine shaft, and certainly some portions of it might wear away through natural processes over millions of years. But if it covers tens of thousands of square miles (as it in fact does), it would be very easy for a city of a few square miles to remain hidden indefinitely, even if the buildings are made of wood or brick. And my point is that any “city of a few square miles” (which is a _huge_ city by premodern standards - ancient Babylon was 900 ha - 3.5 sq miles, and it was enormous for its time) is going to be just the apex of an entire pyramidal supporting structure of culture and artefact, not all of which is going to be covered up. > [@](#): > > It’s asking if it’s _utterly impossible_ that we wouldn’t have found evidence of a civilization, which might have been confined to a small area. And we’re saying there’s no such thing. > [@](#): > > Someone above said it’s just living in cities Not “just”, but cities are **necessary** for a civilization. It’s what we mean by the word. I think the word you’re looking for is “culture” > [@](#): > > , but if that’s true, we have to have a very flexible definition of “city” that accepts a non-human premise, and probably one that would include beehives, anthills, or termite mounds. If you’re claiming there’s even a hint of a possibility there was an intelligent insect civilization around at the time of the dinosaurs, you’re going to need a lot more than idle speculation. I’m willing to go on record that such a thing is not just improbable, but impossible. > [@](#): > > More technical definitions I’ve found stress stratification into social classes, but that would disqualify an ideal democracy. That would also, from what we can tell, disqualify the entire Indus Valley civilization… > [@](#): > > Another try at a universal requirement is literacy Nope. _Many_ civilizations were pre-literate. Off the top of my head - Zimbabwe, Inca, Mississippian > [@](#): > > Again, once you agree that we’re not talking about human civilization, we’re sort of winging it. It is not “winging it” to assert that dinosaurs were not telepathic, for fuck’s sake. It’s applying rudimentary science. > [@](#): > > IMO the most reasonable interpretation of a non-human civilization is an organized society where the members work together for the common good, and live in a fixed location. And I still don’t see how to disqualify social insects from that definition. Insect ‘societies’ aren’t self-organized, they’re instinctual. There’s no intelligence there. That’s the difference. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 16, 2014, 6:21pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/35 "2014-05-16T18:21:55Z")
> [@AaronX](#): > > Don’t people looking for intelligent life say one of the conditions is a star with stable output for a long enough time, with no major changes/extinctions? That would disqualify us - we had a major extinction not 65 Ma past…and several before that. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 16, 2014, 6:25pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/36 "2014-05-16T18:25:54Z")
> [@Lemur866](#): > > These guys could have had human sized brains, as well as manipulative tentacles that could do anything the human hand can do and more. _ **Fhtagn** _! ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [May 16, 2014, 7:09pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/37 "2014-05-16T19:09:46Z")
> [@Oakminster](#): > > I think it is unlikely that a society would advance to the point of using iridium without first discovering and using materials that are easier to obtain and turn into some desired product. Dude, I think the concept was that iridium is hard to find _now_ because the folks a hundred million years ago used up all the iridium boulders just lying around … and then, um, shot them into the sun or something! ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [May 16, 2014, 8:08pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/38 "2014-05-16T20:08:20Z")
> [@TonySinclair](#): > > Not 6,000 feet thick, which is the average depth of the lava forming the Columbia Plateau, the example I mentioned. Maybe we could drill a hole through that, or even a mine shaft, and certainly some portions of it might wear away through natural processes over millions of years. But if it covers tens of thousands of square miles (as it in fact does), it would be very easy for a city of a few square miles to remain hidden indefinitely, even if the buildings are made of wood or brick. There’s actually some pretty good fossil localities located between flows in flood basalts, the Gincko petrified forest in Washington being one of the most famous. Getting clobbered by a flood basalt might actually improve a location’s chance of getting preserved. But that’s not really all that relevant. If you’re going to say this hypothetical civilization is somehow geographically limited to a small area, you don’t need to dream up any elaborate scenarios like them getting buried under a few KM’s of lava-- the fossil record consists of some tiny percentage of a percentage of the total assemblage of life and so the chances of such a spatially limited civilization showing up are fairly slim in any environment. I’d also agree with the others that an intelligent species getting to “civilization” (whatever you want to call it) without also spreading over a wide geographical area is probably not too likely, but with a sample size of one who knows? ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [May 16, 2014, 8:18pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/39 "2014-05-16T20:18:24Z")
> [@MrDibble](#): > > It’s [the SI prefix](http://en.wikipedia.org/wiki/Year#SI_prefix_multipliers) for “Million years” from the Latin _megaannus_ [snerk]. In geological/palaeontological contexts, the “ago” is usually implicit. Cool! Thanks! Best part of these threads is the stuff one learns! > [@](#): > > . . . But the kind of culture that’s filling teeth is the kind of culture that would leave lots of other traces, IMO. Grin! True; if my bicuspids can get fossilized, so can the Golden Gate Bridge! ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [May 16, 2014, 8:20pm UTC](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558/40 "2014-05-16T20:20:36Z")
> [@GreasyJack](#): > > There’s actually some pretty good fossil localities located between flows in flood basalts, the Gincko petrified forest in Washington being one of the most famous. Getting clobbered by a flood basalt might actually improve a location’s chance of getting preserved. > > But that’s not really all that relevant. If you’re going to say this hypothetical civilization is somehow geographically limited to a small area, you don’t need to dream up any elaborate scenarios like them getting buried under a few KM’s of lava-- the fossil record consists of some tiny percentage of a percentage of the total assemblage of life and so the chances of such a spatially limited civilization showing up are fairly slim in any environment. > > I’d also agree with the others that an intelligent species getting to “civilization” (whatever you want to call it) without also spreading over a wide geographical area is probably not too likely, but with a sample size of one who knows? I would argue though that fossilization is a rare event requiring very specific conditions, while the remnants of civilization - at the very least, stone tools, but also possibly carved rock and pottery, depending on how advanced a civilization you have - would survive without any special preservation conditions necessary. [Previous page](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558.md?page=1) [Next page](https://boards.straightdope.com/t/is-it-utterly-impossible-civilization-existed-on-earth-100-million-years-ago/688558.md?page=3)