1892.] AREY STRATA IN ROCHESTER. ICC 



Five or six hundred feet southwest of Pike's quarry on a slight 

 rise of ground is Nellis' lime kiln, where for forty or -fifty years the 

 upper two layers of rock have been burned, while those below have 

 been sold as building stone. These upper layers each about two feet 

 thick are a magnesian limestone, dark grey when freshly fractured but 

 weathering to a light brown, they are badly broken but clearly in 

 place and become particularly interesting on account of the great 

 number of strange fossils which they contain. 



Rocks resting on the New York Niagara limestone would be 

 likely to represent Chicago and Racine beds, the much abused 

 Guelph beds or a new formation, and in order to determine 

 whether the new fauna corresponds with that of either of the above 

 formations a study of the general characteristics of each fauna was 

 made. 



In the table which follows the numbers of species of each class 

 found in various outcrops of rocks of the Niagara epoch are given. 



The first column is based upon the collection which I have been 

 able to make from these layers, the second column gives the number 

 of Canadian Guelph species described in Vols. I. and III. Paleozoic 

 Fossils also including those incorrectly attributed to the Onondaga 

 Salt Group in Vol. II Pal. of N. Y. The third column, the Wisconsin 

 Guelph fauna, is from Vol. IV, Geology of Wisconsin. 



The fauna of the Racine limestone is based upon Professor 

 Hall's paper published in the Regents' Twentieth Annual Report 

 on the Condition of the N. Y. State Museum. 



The Chicago limestone fauna here given includes the species 

 described in the twentieth report above mentioned, and also those 

 described by Winchell and Marcy in their paper read before the 

 Boston Society of Natural History in 1865 and such of those described 

 by McChesney in 1861 as s'eemed to be distinct species. 



The twenty-eighth report of the N. Y. State Museum of Natural 

 History was taken as representing the fauna of the Waldron 111. 

 shale, and the remaining columns are mainly as given in Vol. II. of 

 the Paleontology of New York. 



The numbers given do not include all the fossils which have 

 been described from the different localities, but it is believed that 

 neither the discoveries which have been made since the works upon 

 which they are based were published, nor those which may be made 

 in the future will materially change the characteristics of the various 

 faunas. 



