Fossil Story Essay Example for Free

Fossil Story Essay northeast Illinois has a great voltaic pile of geological history hidden beneath the surface. If you just take a trip to the Larson Quarry or even nether region 11 you can find some interesting joggle formations as comfortably as fossils in them. But, if you cannot get to these aras, this paper can tell you what you can find in 5 different locations in Northeastern Illinois. We will be looking at Larson Quarry, Thornton Quarry, Mazon River, Pit 11, and the Glacial grade which is at Palos Hills and throughout the surface of the dinero ara). The first stop is the Larson Quarry. This is located near DeKalb, Illinois. The specific coordinates are 42? N, 88? 35 W at 920 feet. This site contains specimens from 450 million old age agone which entangle trilobites like Flexicalymene, brachiopods like platystropia, rafnesquina, leptaena, the horn coral streptelasma, an unnamed bivalve, bryozoans, various crinoid stem parts, the cephalopod endoceras, and the gas tropods cyclonema and malcurites.The rock and roll types and formations that were set up around these fossils were Cincinnatian Maquoketa Shale and Galena Dolomite. The Maquoketa shale, which contains seams of argillaceous dolomiteand ranges from highly to slightly weathered, with the highly weathered portions having the consistency of a stiff clay and are extremely fissile (Preber). These fossils were preserved by replacement as thoroughly as mold and cast. The Mazon River, which is near Morris, Illinois is located at 41? 20N, 88? 30W at 525 feet.This site had fossils from 290 million years ago and acceptd seed ferns like alethopteris and neuropteris, true fern Pecopteris, horsetail passage parts calamites (trunk), and annularia (leaf whorl), lycopod tree (club moss) parts and bark lepidodendron, and leaf lepidophylites. The rock types were shale and sandstone as well as coal and the formation was Francis Creek. The Illinois State Museum writes in an article about how Francis Creek formation is formed oftentimes of the airfield that we now call Illinois was a mixture of swampy lowlands and shallow marine bays. From the northeast flowed at least one major river system.The river(s) built large deltas through the low swamps and into the shallow bays. The mud that the river(s) carried was deposited in these deltas and bays. This mud turned into a rock called the Francis Creek Shale. The preservation type was impressions in concretions. Next is Pit 11 which is the Mazonia/Briadwaood State Fish and Wildlife area at 41? 15N, 88? 15W at 590 feet. These specimens were found from 290 million years ago. The fossils include the same basic plants as the Mazon River.They also include jellyfish like the essexella, the shrimp belotelson, clams like edmontia and aviculopectin, an unnamed marine annelid worm, a feasible fish fossil coprolite, the infamous Tully Monster tullymonstrum, and the echinoderm sea cucumber holothurian. The rock types that held these fossils we re shale and sandstone, as well as coal. These were in a Francis Creek formation. These fossils were preserved by impressions in concretions. It becomes quite apparent that there are certain biases in how and what fossils are preserved.Some species, notably Pecopteris unita, are found with fertile structures nearly fractional of the time while others like the more common true fern, Pecopteris acadica, are rarely seen with fertile structures creation preserved at all (Mazon Creek). This tells us how these fossils were formed. Thornton Quarry, at coordinates 41? 35 N, 87? 35 W at 590 to 250 feet, is located on the south side of stops. This Quarry was formed 420 million years ago and includes fossils such as the trilobite calymene, brachiopod pentamerus, corals like favosite and halysites, an unnamed crinoid stem and the cephalopod moorecoceras.The rock types that were here were limestone-dolomite in Niagaran Racine Dolomite with fossils in mold and cast. The most famous reef unearth ed in the Chicago area is the coral reefDebris from the growing reef began to be deposited and cemented. The reefs contained sea lilies, animals resembling horseshoe crabs, and antediluvian ancestors of squids and octopuses up to ten feet long. The ashy, gray-white limestone mined from the Thornton Reef contains the fossils of these animals (Herweck). The basis that there are multiple types of coral is because this area was at the bottom of the Silurian Sea and molded well into the limestone.Lastly, we visit Palos Hills which includes the Glacial Drift. This area was from 15,000 years ago and showed deposits of unconsolidated pebbles, sand, silt ad clay which contain mixed rocks of 400 million to 1 zillion years old at 41? 41N, 87? 50 W at 772 feet. The fossils found here are mammoth or mastodon remains that are preserved as unedited hard parts. There are also mixed marine fossils including crinoid stems, brachiopods, corals like hexagonaria (Petosky Stone) and trilobite parts, where were preserved as mold and cast r replacement.The glacial till include striated rocks composed of a mixture of some types including sedimentary (limestone/dolomite), igneous (granite, basalt) and metamorphic (gneiss). The formation was Valparaiso Moraine. At this time, glacial ice covered the entire Chicago region. the active ice sheet retreated into the Lake Michigan basin, although stagnant, melting ice remained behind. The ice because rapidly re-advanced to theValparaiso moraine in the western Chicago region (Grimm).The glaciers that were in Chicago made a sorry impact on picking up rocks and sand and dirt from other regions and bringing it into the area, which is a reason why you may find interesting things in the area and that rocks age from 400 million to 1 billion years ago. The areas that we can find an assortment of fossils and rock formations are abundant in Illinois and gift a wide variety of ages. From this summary, you can see what type of rock are around Nort heastern Illinois and what type of animals, plants, and rocks were around from different periods and what type of environment they must have lived in.