Handbook of Paleontology 327 



Williamson shale, but the true Williamson overlies the 

 true Wolcott limestone which does not appear in the 

 Rochester section, as also the true Sodus beneath the 

 Wolcott. The Sodus shale (Hartnagel '07) like the Bear 

 Creek shale consists mainly of purple shales with thin 

 layers of highly fossiliferous pearly limestone, and has 

 a fauna of the same general aspect. The name is from 

 the town of Sodus in Wayne county where there is a 

 thickness of 55 feet or more. This shale is not present 

 in the Rochester section. At Wolcott, Wayne county, 

 it has a thickness of 40 feet ; at Lakeport, Oneida county, 

 of 31 feet, thence thinning eastward. In the Clinton sec- 

 tion the Lower Clinton is perhaps represented only by 

 the initial deposit of Oneida conglomerate (see discus- 

 sion of Middle Clinton). Varieties of two species of 

 Anoplotheca are found {A. hemispherica and A. pli- 

 catida). Lobate forms (four species) of the ostracod 

 genus Zygobolba occur. The Wolcott limestone (Hart- 

 nagel '07) receives its name from Wolcott in Wayne 

 county where it has a thickness of 22 feet. Westward 

 it pinches out rapidly, being entirely absent in the Roches- 

 ter section. In an easterly direction it thins less rapidly, 

 having a thickness of 18 feet at Lakeport, but it does 

 not appear in the section at Clinton (Oneida county). 

 The occurrence of the brachiopod Pentamerus oblongus 

 has given this dark gray, fine, even-grained, sometimes 

 dolomitic limestone, the name "Upper Pentamerus." The 

 Sodus shale below with its two species of Anoplotheca 

 and variety of ostracods is a typical Atlantic Silurian 

 association ; while the Wolcott limestone fauna has no 

 ostracods, lacks the Anoplothecas and is made up of 

 types of bryozoans and brachiopods that came in with 



