XIX. 



of the Eifel in western Germany, and in the Ardennes on the 

 borders of France and Belgium. The same species is found 

 in the Lower Devonian rocks of South Devonshire. If, as is 

 held by many authors, the two species are identical, Roemer's 

 name must give way to the earlier one of Conrad. The 

 "Caudagalli epoch" is named from the peculiar sea-weed, the 

 Spirophvton (Taonurus) caudagalli, which abounds in the 

 rocks formed during that epoch, while the "Hipparionyx 

 epoch" is so called after the brachiopod Orthis hipparionyx 

 ( Hipparionyx proximvs ) . 



The rock formations have, with few exceptions, received 

 their names from typical localities in New York State. Thus 

 Chemung is derived from Chemung Narrows ; Portage from 

 Portage on the Genesee River ; Naples from Naples, Ontario 

 County, (the two shales comprised under this name, i. e. the 

 Gardeau and Cashaqua, having received their names from 

 the Gardeau flats on the Genesee, and from Cashaqua Creek, 

 respectively); Genesee from the Genesee River at Mt. Morris; 

 Tully from Tully, Onondaga County, (this rock is absent 

 in the Eighteen Mile Creek region); Moscow from Moscow, 

 Livingston County; Hamilton from Hamilton, Madison 

 County; Marcellus from Marcellus, Onondaga County; 

 Helderberg (both upper and lower) from the Helderberg 

 mountains ; Onondaga from Onondaga County ; Schoharie 

 from Schoharie County, and Oriskany from Oriskany Falls, 

 Oneida County. All of these localities exhibit typical 

 exposures. The other names, viz, Encrinal (crinoid bearing) 

 and Corniferous (chert or hornstone bearing), are names 

 derived from the character of the rock. 



When we study the rocks in greater detail, we find in them 

 associations of fossils which do not occur above or below a 

 certain level. This association is called a fauna. The Cen- 

 tury Dictionary definition for fauna is: "the total of the 

 animal life of a given region or period ; the sum of the 

 animals living in a given area or time." Thus the Lake Erie 



