216 NEW YORK STATE MUSEUM 



to 5G0 feet on Mt Royal at Montreal, are found at successively 

 lower levels in the Champlain valley, and the upper limit at 

 which shells have so far actually been found passes below the 

 level of Lake Champlain at Ticonderoga. 



All the beaches whether marine or lacustrine in the Cham- 

 l>lain district on the New York shore occur therefore within 

 the ranji:e of possible marine surfaces as indicated by the fossils. 

 The fossils alone do not therefore suffice to fix any one of the 

 levels as the upper marine limit. Independent evidence must 

 be advanced to show what and how many of the higher beaches 

 were like those of Lake Iroquois, on the west of the Adirondacks, 

 formed in an ice-dammed lake. 



A comparison of the line, drawn through the highest known 

 localities of marine shells at the eastern base of the Adiron- 

 dacks, with the line showing the upper marine limit in that 

 field shows that the fauna composed of S a x i c a v a r u g o s a , 

 Macoma groenlandica, Mytilus edulis, and a 

 species of Balanus falls off in elevation toward the south at prac- 

 tically the same rate as the phenomena which are taken to indi- 

 cate the highest stand of the ocean waters. As sea level, during 

 the uplift of the land, stood in succession at all points below the 

 upper marine limit, it is not always possible to determine the rela- 

 tion of the sea to the land when au}^ particular deposit of shells 

 was made; but if this upper range of shells in this district affords 

 any ground for an assumption as to the upper marine limit in the 

 inland waters on the north side of the Adirondacks it is to be 

 presumed that there also the upper marine limit will be found 

 closely coinciding with the highest shell deposits when these have 

 been more fully ascertained. 



NOMENCLATURE OF THE MARINE DEPOSITS 



Each generation of men as it comes into possession of its in- 

 heritance of facts and theories in any department of science 

 and gains knowledge of its own, finds something unsuitable in 

 the names applicable to views and bodies of fact whose limits 

 and relations have in their hands come to be notably changed. 

 In the course of the collection and comparison of data centering 

 about some early observed phenomenon the name of the type 



