Introduction

The geologic history that is recorded in derekwadsworth.com"s bedrock covers much more than half a exchange rate years. Over this period of time a variety of geologic processes consisting of erosion and sedimentation, mountain-building, deformation (folding and faulting), metamorphism, and igneous activity, have acted to develop the facility bedrock geology that we see today.

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The theory of "plate tectonics" defines the pressures that cause these geologic processes. Simply put, this theory states that the surface ar of the planet is made up of a series of "plates" that space constantly in motion. Granted, it"s "slow" motion, yet over hundreds of millions the years, the earth"s continents have moved good distances. The soil masses that room in northern climates today may have been in tropical regions numerous years ago. Through mapping the end the distribution of certain fossils, ancient oceans and continents can be delineated. Because that example, a certain Mesozoic fossil (Mesosaurus) occurs only in west Africa and in eastern south America, which reflects that those continents were next to each various other in Mesozoic time. Top top the various other hand, fossils of specific marine shellfish (brachiopods) that Silurian age in seaside derekwadsworth.com and new Brunswick are different from brachiopods that the same age in western new England and northern derekwadsworth.com. This shows that land that is now connected was not linked in the Silurian. An man map will assist you visualize how the earth"s continents have moved end time.

There is a rich diversity the life maintained in derekwadsworth.com"s rocks. While many of the deposits room marine, there room some terrestrial deposits, consisting of the human being famous Trout Valley formation from i beg your pardon the State Fossil, Pertica quadrifaria (a plant) comes. Derekwadsworth.com"s radical fossil record is contained in rocks native the Cambrian, Ordovician, Silurian, and Devonian durations -- a expectations of time from 545 million years ago to 360 million years back (refer come the geologic time scale). Over this span of time, the climate and also location that "derekwadsworth.com" have changed dramatically. Click the adhering to links to watch a "snapshot" of the location of "derekwadsworth.com" and the climate during the time durations indicated:

countless years ago Location of continent Climate
Present day Modern
360-417 Devonian Late Devonian center Devonian at an early stage Devonian
417-440 Silurian Silurian
440-505 Ordovician Middle and also Late Ordovician early on Ordovician
505-545 Cambrian Middle and also Upper Cambrian beforehand Cambrian

Unfortunately there is a far-ranging gap in derekwadsworth.com"s fossil document from approximately 360 million years earlier to about 1 million years ago. This space is most likely the an outcome of episodes of mountain-building and erosion which eliminated the record of rocks formed during this time period. Many recently, continent glaciers scoured the landscape, removing much more sediment and rock. When this erosion was helpful in exposing the older, Paleozoic rocks, it completely removed every one of the Mesozoic material and also a large portion the the Cenozoic record.

Common Fossils found in derekwadsworth.com Bedrock

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Brachiopod The most abundant fossil in derekwadsworth.com. Brachiopods space marine, shelled organisms that stayed in both shallow and deep water environments. Brachiopod shells superficially resemble seashells shells. However, there is a trick to differentiating in between the two. Brachiopods space bilaterally symmetry perpendicular to the hinge line (where the 2 valves touch), vice versa, clams room bilaterally symmetry parallel come the hinge heat (each valve is a mirror picture of the other).
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Coral specifically marine organisms, colonial and also solitary forms. Secrete an external carbonate skeleton. Most restricted to shallow waters, although part are discovered in deeper waters. Some created reefs.
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Clam Freshwater and marine shelled organisms occupying many different environments. Different types may live on, within, burrow v or connect to the soft seafloor or hard substrates.
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Crinoid additionally known as sealilies, these stalked, naval invertebrates space analogous to an reverse starfish on a stem. Your mouth is situated in the center of the cup and the arms assist in food collection. Soft-bodied and calcified specimens are still present today, although the carbonate forms are minimal to deep ocean waters.
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Graptolite Marine, early american organisms which lived in a proteinaceous skeleton. Every "tooth" top top the blade held a soft-bodied animal. Colonies floated, to be attached come the seafloor or flourished on other organisms.
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Stromatoporoid naval sponge with an internal, basal calcareous skeleton. The living surface of the sponge grew on peak of the skeleton. Growth behavior varied depending on environment; some created reefs.
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Snail Freshwater, marine, and terrestrial organisms, generally possessing an outside shell the is coiled. Most snails crawl follow me the seafloor or ground, yet some can swim.
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Trilobite maritime arthropods that dominated the seas throughout the Cambrian and Ordovician Periods. They most likely grazed on dead organics. Every individual walk through several molts (shedding the the exoskeleton) as it matured native a youth to and adult. In fact, most trilobite fossils are most likely the cast-off exoskeleton, not the entirety organism.
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Trace Fossils this fossils include any type of imprint left by an biology activity, consisting of feeding, resting, walking or burrowing. Fecal pellets are also included. Because the organism is rarely maintained making this marks, the is regularly impossible to determine their specific origin.
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Credits because that line drawings:

Stromatoporoid - Boardman, R. S., Cheetham, A. H. And Rowell, A. J. (editors), 1987, Fossil Invertebrates: Blackwell Science, MA, p. 124.

Coral - Moore, R. C., Lalicker, C. G. And also Fischer, A. G., 1952, Invertebrate Fossils: McGraw-Hill publication Company, Inc., NY, p. 124.

Brachiopod - Moore, R. C., Lalicker, C. G. And also A. G. Fischer, 1952, Invertebrate Fossils: McGraw-Hill publication Company, Inc., NY, p. 240.

Bivalve - Moore, R. C. (editor), 1969, writing on Invertebrate Paleontology, part N, Volume 1, Mollusca - Bivalvia: Geological culture of America and the university of Kansas, p. 300.

Snail - Moore, R. C. (editor), 1960, treatise on Invertebrate Paleontology, part I, Mollusca - Gastropoda: Geological culture of America and also the college of Kansas, p. 191.

Crinoid - Babcock, L. E., 1996. Thing 7- Phylum Cnidaria, in Feldman, R. M. (editor), 1996, Fossils the Ohio: Ohio division of geology Survey, Bulletin 70, p. 251.

Trilobite - Moore, R. C., Lalicker, C. G. And Fischer, A. G., 1952, Invertebrate Fossils: McGraw-Hill book Company, Inc., NY, p. 491.

Graptolite - Bulman, O. M. B., 1970, writing on Invertebrate Paleontology, component V, Graptolithina: Geological culture of America and also the university of Kansas, p. 133.

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Trace Fossil - Orr, P. J. And also Pickerill, R. K., 1995, trace fossils from at an early stage Silurian flysch of the Waterville Formation, derekwadsworth.com, USA: Northeastern Geology and Environmental Sciences, v. 17, no. 4, p. 399.