o2 Geology of Hudson County, Neto Jersey. 



than to determine the former presence of glaciers on a grand 

 scale in Hudson County. These glaciers retreated northward 

 as this geological winter drew to a close, leaving behind the ma- 

 terial that had been ground out and carried away from the un- 

 derlying rocks ; this moraine profonde covers nearly the whole 

 surface formerly occupied by the glaciers. The material left by 

 meltiug ice is unassorted, and seldom shows any stratification. 

 But the melting of the glaciers caused floods, similar to those 

 now occurring with the opening of spring, save on a far grander 

 scale, which washed away large portions of this glaciated debris, 

 and deposited it elsewhere, more or less perfectly assorted ; the 

 same end was also accomplished when the material was brought 

 within the action of the waves and currents of the ocean or 

 rivers. Examples of this modified drift, showing irregular layers 

 of sand, gravel, and small boulders, all worn and rounded, may 

 be seen on the western side of Bergen Hill near West End, and 

 from there northerly along the western base of the hill. At 

 several places in Jersey City near the Hudson, excavations 

 have exi:)osed sections of this stratified drift ; these will receive 

 farther notice in the section devoted to surface geology. 



These beds in Hudson County yield a fine quality of building- 

 sand, and also coarser sand and gravel, well adapted for making 

 some kinds of mortars and concrete ; the beds are always 

 irregular, but sometimes of considerable importance. Among 

 the economic uses of the drift, we should perhaps mention the 

 abundant boulders, which furnish material suitable for the ruder 

 kinds of masonry. 



^oUan Sands. — All along the western border of Hudson 

 County, where the upland meets the waters of Newark Bay, or 

 the swamp-deposits extending some distance northward, there 

 occur hills of fine, yellow, loamy sand, resting on the drift; from 

 their structure, it is evident that these hills and mounds are 

 true sand-dunes, formed of blown sand, that must have been 

 j)iled up along the borders of the county before the accumula- 

 tions of peat and mud now filling the swamps. 



At Constable's Point, this fine yellowish sand covers nearly 

 the entire hill, the highest part of Avhicli is about fifty feet above 

 high tide ; the central jwrtion, however, is made up of drift 



