20G NEW YORK STATE MUSEUM 



the upliliL'd seashore as the length of the line has to the extent of 

 the old shore line above the jn-escut sea level within the limits of 

 the {State in a uoithsouth direction. Imagine a diagonal line pass- 

 ing fi'om the top of the thickened black line on the right hand end 

 to the bottom of the line on the left hand end. Then the inclina- 

 tion of this oblique line will slope at the same angle or rate a mile 

 as does the upper marine limit of the Ohamplain submergence. 

 The rate of rise of the upper marine limit is on this basis 4.411 

 feet to the mile to the north. 



MARINE DEPOSITS OF THE CHAMPLAIN VALLEY 



Lithologically the marine deposits of the Champlain valley are 

 commonly referred to as clays but while this facies of the deposits 

 is most striking in the vicinity of the lake, the area exhibits the 

 normal threefold development of sediments under the transgres- 

 sion of the sea : viz, along the shore line, beaches and bars of 

 pebbles and shingle together with stream deltas of sand; farther 

 oft", sandy bottoms; still farther from the shore line, clays. 



In the case of the Champlain valley, the normal character of 

 the three belts or zones of marine deposition is largely modified 

 by the composition of the glacial drift previously laid down in 

 the region. Each of the zones above named may exhibit boulders 

 and coarse rubbh' material. Furthermore, in the retreat of the 

 sea or rather the rise of the land, each belt in turn has been passed 

 over by the shore of the sea and the processes peculiar to the lit toral 

 zone have more or less strewn coarse waste over the sea bottom of 

 the preceding stages. In general, however, there is a cobblestone, 

 shingle, or pebbly zone on the foothills bordering the lake, a sandy 

 zone over the flats at variable distances from the lake shore, and 

 a clay zone adjacent to the lake. The zones are of very variable 

 width on the New York side of the lake, all of them becoming 

 narrower toward the southern contracted end of the present lake. 



Out of the sandy and the clay zone rather characteristically rise 

 older deposits of glacial till or gravels, which for a time existed 

 in turn first as shoals and then as wave-washed isles in the reced- 

 ing sea. These hills have generally lost their original outline as 

 drumlins or morainal mounds with kettles. At top a beach or bar 

 has been heaped by waves and gravels and sands have been washed 

 down the sloping sides, the finest sediments being strewn over the 



