Dentalium Attenuatum

The author and his colleagues specifically chose to focus on 375 million year old rocks in their search for fossils because this was the time frame that provided fish that would be useful to study from. The 385 million year old rocks provided fish that look too similar to the ones we have now and the 365 million year old rocks have fossils that don’t resemble fish. The 375 million year old rocks, however, provide fossils that show the transition between fish and land living animals.

Sedimentary rocks interpret dinosaur habitats through encased environmental structures of the past. Through sedimentary rocks, paleoecologists’ can examine the arranged formation of sedimentary structures to specify what type of environment the dinosaurs’ lived in. An example of a specific sedimentary rock structure can be seen through formed weathering and ripple marks by how wind and sand formed distinct patterns in the past layered sediment. These arrangements provide interpretations on the structure of the sediment and the habitat of encased fossils, through modern day comparisons

During the Cambrian Period there was an explosion of life forms. Most of these were in the water. Many animals with no backbones lived in the shallow seas. These animals were invertebrates.

In a broader study of several national parks in Alaska, conducted in October 2009 by Robert B. Blodgett and David. M. Rohr, documented the varied and abundant marine invertebrate fossils. The team studied Paleozoic and Mesozoic marine faunas in Wrangell-St. Elias National Park, Denali National Park, Yukon-Charley River National Preserve and Glacier Bay National Park. They found that upper triassic gastropods from the chitistone limestone in Wrangell-St. Elias included a wide variety of early norian gastropods very similar to the fauna of the Hells Canyon region of the boundary of Oregon and

A little, yet intriguing cave west in Knox County, TN is Cherokee Caverns. The Cherokee Caverns is located in 8524 Oak Ridge Highway Knoxville TN 37931 US. The cavern hold up events like music festival, Christmas, and the not so scary Halloween. Outside of the Cherokee Caverns sits a bizarre rock is a Stromatolite, a fossil of old blue-green growth, additionally called cyanobacteria. As the sticky green growth developed, they caught sand and other dregs and different layers would develop. The living beings developed entirely expansive over several years. After some time they got to be fossilized. Since cyanobacteria have the capacity to photosynthesize, researchers trust that these primitive green growth may have been in charge of putting the

Just last year, some researchers stated that the extinct aquatic animal, the ‘Tully Monster’ was a vertebrate, possibly a relative of today’s lampreys. Like a mismatched puzzle, the Tully monster lacks some vertebrate pieces and has others that are the wrong shape, researchers and colleagues report in the March issue of Palaeontology. (Palaeontology includes the study of fossils to determine organisms' evolution and interactions with each other and their environment, their paleoecology).

The Inoceramid clams found in the Niobrara formations leads to the assumption that the mudstone and limestone were deposited at the sea floor. Clams today are mostly found in the deep burrows of mud, and with the principle of uniformitarianism you can deduce that those clams were also most likely living on the sea floor. The clams living at the sea floor would be supported by the fact that the clam fossils were found in mudstone and limestone because mudstone is usually in lower energy environments like the sea

British Colombia in Canada, much like California in the United States, used to be a shallow sea and home to much sea life and is now home to thousands of marine animal fossils. For this reason it is believed that Dinosaur Provincial Park consisted of a lot of sands and muds that are characteristic of costal plains (Sues, Henderson, & Tanke, 2010, pg. 1292). When Sues, Henderson, and Tanke (2010) where going about measuring fossil shifts and the amount of fossils that have been lost they took into account the amount of soil that erodes away every year, the vertical and horizontal distribution fossils found within the park, and large landmarks such as rivers and glaciers that could effect fossils in the area (pg.1293). Accounting for these factors

Subclass – Archeorinthes –*Fossil birds (Jurassic birds of Mesozoic Age). *Flight feathers present. *Long tail without a pygostyle. *Carpals and metacarpals free. *Abdominal ribs present. *Hand reduced to three digits.

often will people think of a nautilus, an organism that is a distant cousin of cuttlefish and squid. These organisms have been dubbed "living fossils" and have been on earth for about 500 million years. The nautilus tends to in front of coral reefs, deep in the ocean. The long existence of the nautilus has allowed its mesmerizing spiral shell to be embedded in some rocks and has become a part of the fossil record.

In modern popular culture, Dunkleosteus is by far the best known and most often represented of the early placoderm carnivores. However Dunkleosteus actually sat within the Dinichthys genus for a long time as the species Dinichthys terrelli. It was not until the large numbers of Dinichthys remains were re-studied that it was realised that a large number of the Dinichthys fossils actually represented different genera, not species. The result was that many of these remains were split to form new genera including the creation of Dunkleosteus. In a further twist however, the species that was split to form Dunkleosteus, D. terrelli, was actually the remains most often used when reconstructing Dinichthys.

Most Cambrian rocks contain fossils of trilobite shells, cap-shaped or flattened shells, and brachiopods (Whittington, 1985). When Walcott went looking for North American Cambrian fossils in August of 1909, he ended up in the Canadian Rocky Mountains. He and his wife found a loose block in the ridge they were searching near, split it open, and found what they later classified the “lace crab” (Briggs, 1994). Walcott knew right away what they had discovered was something different – the soft parts of the crab, such as the limbs, were preserved. During the next season, Walcott and his sons came back to the Shale, searching the slopes along the trail where they had discovered the loose block to find fossil layers. Luckily for them, the Shale rock layers were almost horizontal, and for thirty days a team quarried the ridge. The next year, they spent even longer quarrying. The last year spent quarrying the rocks was in 1917, when Walcott was 67 (Briggs, 1994). The rocks were removed from the ridge using picks, chisels, long iron bars, and small explosives. All the quarrying done by Walcott and his crew resulted in over sixty five thousand fossils, now stored in the

The author and his colleagues chose to focus on 375 million year old rocks in their search for fossils because amphibians that look dissimilar to fish were discovered in 365 million year old rocks, while fish without amphibian characteristics were discovered in 385 million year old rocks. Thus, it is possible that the evolutionary intermediary, or the “missing link” between fish and amphibians, would be discovered in 375 million year old rocks, between the two time periods. The rocks examined were sedimentary in composition, as the gradual and relatively gentle formation of sedimentary rock under conditions of mild pressure and low heat are conducive to the fossilization of animal remains. Sedimentary rock is also often formed in rivers and seas, where animals are likely to live. This site provides a resource that describes means by which fossils are formed and how the fossil record may be interpreted, and shows some examples of fossils demonstrating evolution through geological periods: http://www.fossilmuseum.net/fossilrecord.htm. In 2004, Shubin and his colleagues were looking for fossils on Ellesmere Island, in northern Canada. This location was chosen because of its lack of human development, as well as of obstructing natural formations and life forms such as trees, which

My outside source for questions 3 and 4 is a journal by Pat Shipman titled Fossils. This journal was published in The New Scientist Vol. 215, Issue 2876, p. 8-16.

These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils.