480 



THE AMERICAN NATURALIST 



[Vol. XLII 



The following few dwarf faunas are described in illus- 

 tration of the preceding agencies : 



a. Faunas of the Cobleskill, Rondout, Manlius and 

 Bertie of Xew York. 



b. Faunas of the Pyrite bed of the Tully horizon and of 

 the Clinton iron ore. 



c. Fauna of the Genesee and Ohio shales; Styliolina 

 limestone of New York. 



(I. Fauna of the Windsor (Nova Scotia) Carboniferous. 

 e. Faunas of the Permian. 



/. Upper Cretaceous fauna of Xew Mexico and southern 

 Colorado. 



g. Tertiary lake fauna of Steinheim, Germany. 



h. Pleistocene ! fauna of the lower Hudson River. 



a. The Manlius, Rondout and Cobleskill formations of 

 eastern New York, as well as the Bertie of the western 

 part of the state are conspicuous for their dwarf faunas. 

 The cause was probably in part the greater density of the 

 water and in part the presence of lime mud, making the 

 waters impure mechanically. The section of the rocks at 

 Howes Cave is as follows : 21 



Coeymans, a typical lime sand rock (calcarenite). 



Manlius, a fully laminated lime mud rock (calcilutite) 

 with occasional beds of a lime sand. 



Rondout, lithology as in Manlius but more argillaceous 

 in upper portion. 



Cobleskill (Coralline), lithology about the same as 

 Manlius. 



(Slight disconformity.) 



Brayman (upper Salina), possibly the equivalent of the 

 Bertie of western New York. Shales gray to green with 

 traces of gypsum. Many iron nodules. 22 



(Great disconformity.) 



Lorraine. 



Deposition was probably continuous from the Cobleskill 

 to the Coeymans, as there is no evidence of a stratigraphic 



