NEW YORK STATE MUSEUM 



ceras Barrande). This genus, which by its split septal necks and 

 semiconical rings, closing the siphuncle walls, holds the position of 

 an aberrant group, has been found by Dwight to be well represented 

 in the Beekmantown beds of the neighborhood of Poughkeepsie 

 N. Y., in the southern portion of the " Levis channel." It is well 

 known from the Lower Siluric rocks of the Bohemian and Baltic 

 basins and represents a decidedly foreign element on the American 

 continent, which can be supposed to have entered the channel by way 

 of the Newfoundland embayment. 



In regard to the remaining orthoceraconic and cyrtoceraconic 

 cephalopods it can only be said that all of the genera here cited ap- 

 pear as well represented in the eastern basin (Bohemian-Medi- 

 terranean, Atlantic and Baltic basins) as here; that there are no 

 identical species, such as we later find in the Trenton and that hence 

 a direct connection of the Champlain basin and these eastern seas 

 can not be assumed for the periods here under consideration. There 

 are, however, several species cited in the above given synoptic list 

 from the Champlain basin which are known from the Mingan islands 

 and Newfoundland and therefore would indicate more or less of a 

 connection between the Champlain-Canadian and Newfoundland em- 

 bayments. These are Protocycloceras lamarcki from 

 the Beekmantown beds, Geisonoceras s h u m a r d i , S p y - 

 roceras clintoni and Plectoceras jason from the 

 Chazy beds. Their number, held against the sum total of species 

 known from the Beekmantown beds of the Mingan islands and New- 

 foundland on one hand and the Champlain basin on the other, ap- 

 pears, however, so small that this evidence in regard to a possible 

 connection of the two embayments is to be considered more negative 

 than positive. We have here cited 57 species of cephalopods from 

 the Champlain basin, out of which number these four are identical 

 with Newfoundland and Mingan island species. On the other hand, 

 Billings describes 31 cephalopod species from the Beekmantown and 

 Chazy beds of Newfoundland and the Mingan islands, only six of 

 which he cites as found either in the Canadian or Champlain basin 

 ( O . multicameratum, O. bilineatum, 5 O . sub- 



1 In studying the orthoceracones and cyrtoceracones of the Beekmantown 

 and Chazy formations of the Champlain valley one cannot fail to be impressed 

 with the fact of the extreme similarity of some Chazy and Beekmantown 

 species. In the case of Cameroceras brainerdi (Fort Cassin beds) and 

 Cameroceras tenuiseptum (Chazy) this similarity has been pointed 

 out in the description of the latter species. It is therefore probable that certain 

 Chazy forms were indigenous, being directly derived from Beekmantown forms 

 which formerly occupied the same area. 



