Part II. ma}' be considered an elementary text book of the 

 Palaeontology of this region, as described in Part I. The 

 introductor\' chapter treats of the general principles of 

 Palaeontology, and discusses the methods of fossilization. 

 Chapter I. is devoted to the methods of collecting fossils 

 from the beds of this region, and preparing them for study. 

 Chapter II. treats of the fossils themselves. A brief descrip- 

 tion of the structural characters of each class precedes the 

 discussion of the genera and species in that class. The 

 generic descriptions are given with some detail, but under 

 the species, onlv the leading features are mentioned, these, 

 togfether with the illustrations, being intended chieflv as aids 

 in the identification of the species. References to the most 

 important works are given, and these should be consulted 

 as much as possible. The magnificent volumes of the 

 Palfeontologv of New York, contained in all the larger 

 libraries, are of special importance to the advanced student, 

 and the descriptions and illustrations there given, deserve 

 the most careful study. The species considered are those 

 which have been collected by the author, and those which 

 have been previously described as coming from the Eighteen 

 Mile Creek or Lake Shore region. A few descriptions have 

 been introduced, of species recorded from Erie Coiinty only, 

 but the association of which led to the inference that 

 thev belonged somewhere in the beds described in Part I. 

 While all the species, which have so far come under the 

 author's notice as found in the beds discussed, have been 

 included, no pretension of completeness is made. It remains 

 for the local student to discover new forms for this region, 

 and to find new associations for those here described. 



The plant remains from this region are not described, as 

 the material obtained is very unsatisfactory, with the excep- 

 tion of the spores, which are discussed on pages 15 and 16, 

 of Part I. 



The etvmolog}' of the generic names is, in almost all cases, 

 taken directly from S. A. Miller's admirable reference book: 

 "North American Geology and Palaeontology." 



