rj. NEW YORK STATE MUSEUM 



rived from a part of the limited fauna described in this paper. On 

 account of a lack of uniform application of Hyatt's systematic prin- 

 ciples to the taxonomy of the paleozoic cephalopod faunas of other 

 countries, it is as vet impossible to survey the distribution of all 

 genera cited here. Moreover it is apparent, that some of the larger 

 or dominating genera, as Endoceras, are of such general distribu- 

 tion, that only a close scrutiny of their species would promise any 

 results. For these reasons we restrict ourselves to a discussion of 

 the involute forms, which have been the subject of Hyatt's investi- 

 gation in the Phylogeny of an Acquired Characteristic and to the 

 aberrant and highlv specialized genera which, by their very nature, 

 will be bound to more limited areas of distribution and hence more 

 readily yield clews to the former connections of the oceanic basins. 

 It is true and must not be here overlooked that the very aberrancy 

 and specialization of these forms may indicate that they were adopted 

 to special pecuHar conditions and to a very limited facies and the 

 failure to find them over large areas might for this reason be simply 

 due to a failure of exposure of the special facies to which they are 

 bound. But this is the case, in a more general way, with all the 

 Cephalopoda, in our paleozoic formations at least, for the scarcity 

 of cephalopods in both the Beekmantown and Chazy formations and 

 in the Trenton as well — in most localities and in large sections — 

 and their profuse appearance in certain beds or localities, as at Fort 

 Cassin (Beekmantown) and Little Monty bay (Chazy) and the 

 Black river beds of Watertown, is sufficient evidence of their former 

 rather restricted distribution in the paleozoic seas and of their char- 

 acter as facies animals. The probability of a former much wider 

 distribution of the aberrant and specialized forms than their fossil 

 representation would indicate, is further diminished to some extent 

 bv the fact that such forms are as a rule eagerly sought by collectors. 

 ' In discussing the paleogeographic distribution of the cephalopods 

 of the Champlain basin we follow Frech^ in distinguishing between 

 a Bohemian-Mediterranean basin, Baltic basin, North-Atlantic basin 

 and Pacific-American basin. The North-Atlantic basin is supposed 

 to have had an important northwestern embayment, the Newfound- 

 land embayment, which comprises the present maritime provinces of 

 Canada, New Brunswick, Nova Scotia and Newfoundland. From 

 the eastern portion of the Pacific-American basin, the Mississippian 

 sea. there was separated, according to Ulrich and Schuchert- a long j 

 basin, extending over the area of the present Appalachi an system. 



1 Lethaea Paleozoica. 1897. 2 :88. 



^ Sec An. Rep't State Paleontol. for 1901. 



