What is a polystrate fossil?
144408
The term, which is not a geological term, is used by creationists to describe fossils that intersect several rock beds (poly - many, Strate - Strata) (cutting across several strate), usually in sedimentary rocks. However, "polystrate" tree fossils were not problematic for conventional geologists of the 19th century, nor are they a problem for 20th century geologists\nPlease check the link below
973157
Lots. Recently there are several theropod fossils with feathers discovered in a fine-grained Chinese deposit, things like Sinosauropteryx, Caudipteryx and Beipiaosaurus (look them up on wikipedia). These are younger than the famous Archeopteryx, which has a reptilian skull, teeth, digits, claws, vertebrae, sternum, ribs, pelvis and tail, and a few bird traits like a wishbone, wings and feathers. However, older theropods and Archeopteryx have many similar skeletal features and the feathered therapods add further support to the relationship. In younger sediments than Archeopteryx, there are several fossil species with more birds-like traits, such as Sinornis and Shenzhouraptor and dozens more (wikipedia "fossil birds").
755167
This is an excerpt from the referenced website:\n"Recovery of diagnostic ankle bones in the skeletons of primitive protocetids during our field work in Pakistan in 2000 confirmed their derivation from Artiodactyla (the mammalian order including cows, deer, hippos, etc.), and showed convincingly that whales did not originate from mesonychid condylarths as Van Valen hypothesized (and we had expected)."\n\nHope this helps.
599488
I need more context.  What's the backstory?\n\nI'm panting to help.....\n\nOk, try coprolite or use coprolitic as an adjective.\n\n(Fossilized excrement)
495022
Examining fossils- they tell us a lot about once living things like appearance & behavior. Fossils include everything from dinosaur bones & eggs to worm burrows, fossilized tracks, fossilized poop, etc.\n\nStratigraphy or the laying down of sediments over time. This tells us a lot about when & where water occurred. Ripple marks & dunes created by winds. Escarpments carved by the ocean.\n\nGeochemistry involves looking at different isotopes to tell what things were like once.
861869
The major lines of evidence are:\n1) the paleoenvironments the species lived in, as evidenced by the sedimentary rocks and other fossils\n2) analogy with related species\n3) functional morphology\n4) taphonomy and trackways\n\nThings you might look up are ammonites, trilobites etc
761767
Birds evolved from a group of therapod dinosaurs. "Transitional fossils " do exist, the most famous been the Jurassic  Archaeopteryx, which had a teeth like and a long bony tail a reptile, but feathers like a bird. Beautifully preserved specimens have been found in fine grained  Solnhofen limestones in Germany .
1075116
Structures resembling remarkably preserved bacterial and cyanobacterial microfossils from ~3,465-million-year-old Apex cherts of the Warrawoona Group in Western Australia currently provide the oldest morphological evidence for life on Earth and have been taken to support an early beginning for oxygen-producing photosynthesis. Eleven species of filamentous prokaryote, distinguished by shape and geometry, have been put forward as meeting the criteria required of authentic Archaean microfossils, and contrast with other microfossils dismissed as either unreliable or unreproducible. These structures are nearly a billion years older than putative cyanobacterial biomarkers, genomic arguments for cyanobacteria, and oxygenic atmosphere and any comparable diverse suite of microfossils. Here we report new research on the type and re-collected material, involving mapping, optical and electron microscopy, digital image analysis, micro-Raman spectroscopy and other geochemical techniques. We reinterpret the purported microfossil-like structure as secondary artefacts formed from amorphous graphite within multiple generations of metalliferous hydrothermal vein chert and volcanic glass. Although there is no support for primary biological morphology, a Fischer-Tropsch-type synthesis of carbon compounds and carbon isotopic fractionation is inferred for one of the oldest known hydrothermal systems on Earth.
297873
The era you are asking about is Jurassic (it was between the Cretaceous and Triassic period). As for the fastest dinosaur in this era, if what Paleontologists have found is correct, I believe it was Compsognathus.
401064
Scientists look for a great many things.\n\nScientists want to know what the Earth used to be like.  They look at fossils, among other things, to find out.\n\nPretty much every aspect of fossils is examined.  Given any on fossils, scientists will be trying to determine:\n\n* How the individual lived.\n* How it died.\n* What died with it.\n* What it says about the larger world.\n\nFor instance, scientists know that some Sauropod dinosaurs (ones like Brontosaurus) lived in herds because they frequently trampled on each other's tails.  Sauropod tails have large numbers of these minor injuries, suggesting such tail damage was common.\n\nA single fossil will be examined for bone damage to see what killed it.  Sometimes, they can identify the species of animal that attacked the the fossil.  They also look for traces of scavengers afterwards, and even decay processes!\n\nFossils of animal dung are examined to see what was being eaten.  These are called coprolites.\n\nFossils of "supersized" insects in the ancient past tell us that the oxygen in the atmosphere used to be much higher.  Today, an insect that large would suffocate.\n\nEvery aspect of a fossil is examined.  How big it was, how fast it grew (from growth lines), everything.\n\nIt's a detective story!  Come help us figure it all out!
164872
Where is Calimecita when you need her!!!\n\nArchaeopteridales\n(Upper Devonian to Mississippian)\nPerhaps one of the most remarkable paleobotanical discoveries is the work done by Charles B. Beck in the 1960s. Through careful and painstaking work, he was able to demonstrate that the fossil wood known as Callixylon and the leaves known as Archaeopteris, shown at left, were actually part of the same plant. This may sound trivial, until one realizes that the fossil record seldom preserves whole organisms intact. \nIn the case of Archaeopteris, the leaves were reminiscent of ferns, and in fact produced and released spores in a manner consistent with this interpretation. As a result, they were considered to be some sort of fossil fern. The wood Callixylon, by contrast, was considered similar to modern conifers, and was placed with the seed plants. When Dr. Beck demonstrated that fossils of Archaeopteris were physically attached to Callixylon wood, it was realised that the plant, now collectively called Archaeopteris, was actually an extinct group of plants unlike any living plants today -- it had both wood and fern-like reproduction. \n\nYes...........I cut and pasted. (Hoping it would all make sense to you!!)
1092991
Try a museum of natural science.  You can find all kinds of fossils there.
416007
Its a kind of prehistoric turtle.
418542
Pterosaurs do indeed rock.\n\nBut my favorite Mesozoic creatures are the ammonites.  I love those shells with their complicated septa (dividers) inside!  So beautiful, so mysterious.\n\nWhy are they extinct?  WHY?  *sniff*\n\nI'm also fond of a reptile (like the pterandons, not a dinosaur) called Longisquamus.  I just like to say Longisquamus.  It's neat!  It's got huge... somethings sticking out of it's back.  We don't really know what, skin flaps maybe.  It looks weird, what more do you want out of an extinct animal?  :-)
458581
Geologic time goes back millions, if not billions of years. For example, dinosaurs first appeared on earth between 200 and 240 million years ago, in a time period known as the Triassic. They lived through the Jurrassic until the Cretaceous (65 million years ago) periods. \nIn short geologic time is a time scale that has been put together based on fossil and other evidence to depict the earths past from formation (4.5 billion years ago) to present time.
77663
Adapted from Dinosaurs: The Very Latest Information and Hands-On Activities From the Museum of the Rockies, by Liza Charlesworth and Bonnie Sachatello-Sawyer. A Scholastic Professional Book.\n\nWay back in 1676, Robert Plot, the curator of an English museum, described and drew a thigh bone that he believed belonged to a giant man. Although that fossil disappeared without a trace, the surviving illustration suggests that it may well have been part of a "Megalosaurus." Later, in 1822, large teeth discovered in England by Mary Ann Mantell and her husband, Gideon, were thought to be the remains of a huge and extinct iguana. It wasn't until 1841 that British scientist Richard Owen came to realize that such fossils were distinct from the teeth or bones of any living creature. The ancient animals were so different, in fact, that they deserved their own name. So Owen dubbed the group "Dinosauria," which means "terrible lizards."\n\nAcross the ocean in North America, dinosaur tracks were studied in the Connecticut Valley, beginning in the 1830's. They were believed to belong to enormous ravens, freed from Noah's Ark after the Great Flood. At that time, paleontology was long on deduction and short on evidence. This was remedied when two wealthy and competitive American scientists, Othniel Marsh and Edward Cope, raced to excavate fossils in the Rocky Mountain region. In the late 1800's, their separate teams, armed against Native Americans and each other, dug up tons of bones from several sites. All in all, Marsh and Cope's rivalry — known as the Bone Wars — uncovered 136 new species. And their respective fossil displays generated excitement for dinosaurs the world over.\n\nIn the 1900's, enthusiasm for dinosaurs grew steadily, attracting the attention of the scientific community. Institutions such as the Carnegie Museum of Natural History and the American Museum of Natural History assembled dig teams, which uncovered many rich bone beds in North America (as did their counterparts overseas). New sites in Utah revealed several different species, including "Camarasaurus," "Apatosaurus," and "Stegosaurus;" "Tyrannosaurus rex" remains were found in Montana and baby Coelosaurs in New Mexico.\n\nIn recent decades, dinosaur research continues, but the emphasis has shifted from finding and classifying these animals to analyzing and reconstructing their lives and habitats. In the late 1960's, Robert Bakker proposed that these ancient creatures may well have been as agile and energetic as warm-blooded animals. In the mid 1970's, Peter Dodson, along with James Farlow, hypothesized that they used their horns to attract the attention of females, as well as for fighting. And in the late 1970's, Jack Horner made history by identifying some of the first dinosaurs nests and eggs in North America. These important "Maiasaura" fossils helped to determine that some species nested in colonies and cared for their young.\n\nIn the past few years, several paleontologists, including Ken Carpenter, Phil Currie, and William Coombs, have identified juvenile dinosaurs that were previously thought to be adults; and David Weishampel has theorized that some dinosaurs probably used their crests and nasal passages to create sound. Each day, scientists working all over the world, in the field and in research labs, help to redefine the meaning of the world "dinosaur."
404949
Well, I gotta tell you that there's a lot of them.  The paleozoic spans a period from roughly 560 million years ago to roughly 240 million years ago.  There's a LOT of them - the periods are the Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, and the Permian.  Then we go into Mesozoic life.\n\nI guess maybe an answer would be the types of fossils we find: multicellular organisms, with amphibians being the dominant land animal in the later part.  Dinos don't come around much until the Mesozoic.\n\nOther than that, you get all types of sedimentary rocks and forms as you do now.  Hope that sort of answers your question!