150 Agricultural Experiment Station, Ithaca, N. Y. 



ficientlj complete to allow of any full statement of their meaning. 

 Indeed, one of the needs of North American geology is to have 

 some one person follow this subject to an end by tracing the beaches 

 not only to the States, but also through Canada. There is much 

 yet to be learned, though we are in a position to state the more 

 general facts of the history. 



It cannot be doubted that these ridges were formed in water. 

 Their resemblance to the shore lines of the lake is so perfect, in 

 almost every particular, that the conclusion is almost forced upon us 

 that the water in which they were formed was lake water; and this 

 conclusion scarcely admits of a reasonable doubt. No other explana- 

 tion than beach origin can be admitted, for no other possible 

 cause can be found, and if of beach origin, then the beaches were 

 formed either in lake or ocean. In support of the latter hypothesis 

 no single fact can be found which does not equally apply to the 

 theory of origin in lake waters ; and against the ocean theory there 

 are facts which seem to entirely exclude it. If these were formed 

 in the ocean they should be continuous; but the beaches end quite 

 abruptly, the upper one just south of the town of Silver Creek, the 

 next south of the town of Hamburg, and the others and lower ones 

 near Crittenden. There is no known reason why ocean beaches 

 should thus terminate, while, as we shall see, there is an excellent 

 reason why lakes should cease to build beaches at these points. 



Everything then points to lake origin, and all the observed facts 

 may be accounted for by this theory, while no known fact opposes 

 it. Therefore we may consider it more than a theory ; it is a 

 proved fact. There remains to be explained (1) why Lake Erie 

 should have been so much hi2;her than now ; (2) why the beaches 

 end so abruptly, and (3) why they are no longer horizontal. These 

 facts can best be explained in the course of a brief statement of the 

 geological history of the region. 



Resume of the Geological History. 



Before the last geological period, the northern part of New York 

 had valleys and hills, plains and escarpments, very much as at pres- 

 ent, though the details of topography were quite different. Among 

 the more important differences was tlie absence of the great lakes, 

 which occupy valleys that have been transformed to lakes largely 



