PLEISTOCENE GEOLOGY OF MOOERS QUADRANGLE 47 



fossil shells are found along the New York side of Lake Cham- 

 plain at least as far south as the ruins of the old French fort 

 on Crown Point peninsula. The marine waters probably ex- 

 tended as far south as Whitehall; and as will be shown in 

 another report on this special subject that there was no connection 

 by the marine waters southward through Wood creek with the sea 

 at the mouth of the Hudson river at this time, the land on the 

 south being elevated very much in the same proportion as the land 

 in the upper St Lawrence valley was depressed below sea level. 



Marine deposits 

 There is difficulty in distinguishing the marine deposits of 

 this area from, those made by the waters of the glacial lakes. 

 The sole satisfactory local criterion is the presence of marine shells 

 or other fossils in the oceanic series. As already • indicated 

 these deposits occur in the low grounds. On plate 25 the 

 shaded area shows the horizontal extent of the marine deposits 

 according to the determination of the upper marine limit which 

 has been made in this report. In general the marine deposits 

 on this area are stony modifications of the glacial deposits, 

 largely modified till, worked over by waves and currents. The 

 effect of wave action has been to arrange the drift in the form 

 of beach ridges, and waves and currents together have produced 

 bars of gravel or flats of sandy materials frequently changing 

 to gravels or coarse, bouldery deposits. The accompanying map 

 [pi. 26] is not made to show the distinctions between these 

 various phases other than to delineate the recognizable beach 

 ridges. Here and there a plain of sand or gravel marks the 

 delta of a stream as at Mooers and Mooers Forks. The deposits 

 of undoubted marine origin within the area are only a few feet 

 in thickness. Some parts of the submerged area exhibit morainal 

 deposits apparently without alteration as north of Mooers and east 

 of Sciota. The finer waterworn deposits are best developed along 

 the courses of 'the streams and are thus to be regarded as 

 rehandled detritus alternately deposited in deltas and thus car- 

 ried downward about the mouth of the stream as the land rose 

 above the sea. 



