OHIO FOSSILS 



CHAPTER 5. SILURIAN FOSSILS 



Collecting Localities 



GENERAL. The Silurian rocks of Ohio are exposed in broken sequence from the outer 

 edges of the Ordovician outcrop area to the Indiana line to the west, the Michigan line and Lake 

 Erie to the north, and the Devonian contact to the east (see map, fig. 8). Many formations, 

 most of them fossiliferous, are represented in this huge expanse of outcrop (see Table of for- 

 mations, fig. 14). In general, fossils are not as abundant in our Silurian formations as in the 

 Ordovician ones, but they are fully as varied and interesting. They have received less study 

 than the Ordovician forms. Nevertheless, collecting in our Silurian is repaid by a rich harvest 

 of fossils. The possibility of finding in them species unknown to science makes up for the 

 greater difficulties of identification as compared with Ordovician forms. Only a few of the many 

 good collecting localities in the state can be mentioned here. 



HIGHLAND COUNTY. Silurian collecting localities too numerous to mention may be found 

 in this county. Many road cuts expose good sections as do several quarries in the county, espe- 

 cially in the neighborhood of Hillsboro. The best collecting is in the Brassfield, Bisher, Lilley 

 (West Union), Peebles, and Greenfield formations. Only the Alger formation is relatively poor 

 for collecting. 



C LAY CENTER. This locality in Ottawa County, northwestern'Ohio, which is well known 

 to mineral collectors is also a good locality for fossils. The Greenfield, with Whitfieldella , 

 Hindella , and Leperditia , is exposed here as well as the Guelph dolomite with fossils too numer- 

 ous to count, the commoner ones being Fletcheria , Megalomus , stromatoporoids, Trimerella , 

 Favosites, Halysites , Orthoceras, and gastropods. 



CRAWFORD . Just northwest of the town, in Wyandot County, is the type locality of the 

 Tymochtee shaly dolomite from which numerous Leperditia and one specimen of Eurypterus 

 have been collected. 



CAREY. At this place, in Wyandot County, the Greenfield dolomite and the Guelph dolo- 

 mite are exposed. The former has yielded its characteristic fossils, Hindella and Leperditia , 

 and the Guelph a number of gastropods, cephalopods, and brachiopods. 



GIBSONBURG . Quarries north of this.town, in Sandusky County, have yielded character- 

 istic Guelph fossils, especially the pelecypod Megalomus. 



GENOA. The quarries north and southeast of this town in Ottawa County are in the fossil- 

 iferous Greenfield and Guelph dolomites, both of which have yielded abundant fossils. 



MAPLE GROVE. The quarries around this town, 6 miles northwest of Tiffin, Seneca 

 County, are also working in the Greenfield and Guelph dolomites, both fossiliferous. 



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