OHIO FOSSILS 



CHAPTER 4. ORDOVICIAN FOSSILS 



Collecting Localities 



GENERAL . Ordovician rocks are found at the surface in the southwestern part of the 

 state. Fossils may be found almost anywhere within the triangular area bounded by Miami 

 County on the north, the state line on the west from Preble County southward, and on the 

 south from the Indiana line to Adams County (see map, fig. 8). In parts of this area, Ordo- 

 vician fossils are so abundant that they cannot fail to attract attention. It is not surprising 

 to find that collectors began work early in the Cincinnati region and that more than 700 

 species have been described from that area. Some of the particularly good collecting local- 

 ities are noted here but there are many others too numerous to mention. 



In general, fossils from the older formations of the Ordovician may be found in the vicin- 

 ity of the Ohio River and those from the younger formations along the edges of the Ordovician 

 outcrop area (see map, fig. 8). 



CINCINNATI . The city is built on a veritable storehouse of fossils, a storehouse that 

 seems inexhaustible. Sometimes, when building operations are started, a hillside will be 

 stripped of soil, exposing fossiliferous beds from which specimens can be picked up in thou- 

 sands. In the ravines and gullies, where streams are constantly eroding the bedrock, clean 

 rock surfaces are often exposed. Where soft shales are attacked by frost and water, fossils 

 are washed out and exposed in thousands along the soft clayey slopes. In the stream beds 

 themselves, fossils freed from the rock can often be picked up but many of them are worn and 

 not as fresh as those still on the slopes or in the rock. The Cincinnati area has been a col- 

 lecting ground for a century or more but it still yields good specimens in satisfying numbers. 

 See Dalve (1948). 



GREENE COUNTY. In streams and railroad cuts in this county are several exposures 

 of the Whitewater and Elkhorn formations with an abundance of bryozoans, brachiopods, 

 and other fossils. The Whitewater has several kinds of corals and the Elkhorn is notable 

 for good specimens of the brachiopods Hebertella and Platystrophia . 



PREBLE AND BUTLER COUNTIES. The Whitewater and Elkhorn are extensively ex- 

 posed in these counties. Good exposures with abundant fossils are found near the campus 

 of Miami University and in river banks and road cuts in many parts of the two counties. 



FORT ANCIENT, WARREN COUNTY. This is the type locality of the Fort Ancient mem- 

 ber of the Waynesville formation. Exposures in Stony Run contain abundant brachiopods and 

 other fossils. 



BLANCHESTER. CLINTON COUNTY. In this vicinity, the Liberty and Waynesville for- 

 mations, both fossiliferous, crop out and some zones produce an abundance of brachiopods, 

 pelecypods, and some trilobites. 



