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NEW YORK STATE MUSEUM 



are of the middle division. While the Chazy was being de- 

 posited, the remainder of the State seems to have been mostly 

 above sea level, and either the same conditions obtained during 

 Oassin deposition or else a barrier was developed between the 

 Champlain and Mohawk basins at this time, preventing the Cas- 

 sin fauna from reaching the latter area. While the writer is 

 not a sufficiently competent paleontologist to appreciate or dis- 

 cuss the relationships or differences of the Cassin and Chazy 

 faunas, it does seem to him that structurally the Cassin is re- 

 lated to the Chazy rather than to the Beekmantown. The uplift 

 which shut off this basin from the waters of the remainder of 

 the State, and then caused those waters to recede beyond the 

 State's boundaries, took place prior to Cassin deposition, and 

 these conditions persisted during the Chazy, followed by an up- 

 lift and then by the great depression which let in the waters of 

 the Black River and Trenton seas over the whole region. It is 

 true that in the Champlain region there is no natural lithologic 

 boundary between the Beekmantown and Cassin, while the basal 

 sandstone of the Chazy does indicate a physical change. But 

 this is a slight one and not to be compared to the greater ones 

 outlined above. 



Day Point, Crown Point and Valcour substages. The three 

 divisions of the Chazy are sharply marked off from one another 

 lithologically and seem to the writer equally so paleontologically. 

 Moreover, their thickness and importance over most of the Cham- 

 plain region seem to warrant their separation in mapping, a 

 matter easy of accomplishment on the scale of the 1 inch maps. 

 They would seem therefore worthy of separate names. Brainard 

 and Seeley's lines of division can not be improved on, as it seems 

 to the writer, and the following names are suggested for them ; for 

 division A the Day Point limestone; for B the Crown Point lime- 

 stone; and for C the Valcour limestone. These are not intended 

 to replace the group name but simply as indicative of the three 

 well marked substages of the group. Division A is well shown 

 along the lake shore in the northern part of Peru township, is 

 exceedingly fossiliferous there, and in the near vicinity both con- 

 tacts are to be found, the upper at Bluff point, the lower on 



