PLEISTOCENE CLAYS. 129 



a hundred feet thick. Outside the swamp, similar clay occurs at 

 somewhat greater elevations, but yet within the limits occupied 

 by Lake Passaic. At the clay pits south of Morristown (eleva- 

 tion 310-320 ft.) it is overlaid by 2 or 3 feet of glacial till. 

 Three miles south of Morristown, on the property of Mr. F. F. 

 Lippman, slightly stony clay is exposed along the road, its verti- 

 cal range being 30 feet. Between Second mountain and Long 

 hill, along the Passaic and Dead rivers, there is considerable 

 clay at elevations below 225 feet. This clay may in part be post- 

 Glacial, since it is hardly above the present flood plain of the 

 river. 



Northeast of the morainal ridge which extends from Morris- 

 town to Chatham, lacustrine clay occurs at several localities, 

 chiefly alt low levels. Some of it may be in part post-Glacial.in 

 origin, but other beds are wholly of earlier date. The clays 

 found in the marshes along the Whippany river belong to> the 

 former class, while a brownish-blue clay, on the hill midway be- 

 tween Whippany and Hanover, at an elevation of 230 feet and 

 overlain by several feet of glacial till, belongs to the second class. 



North of West Livingston a low area (200 ft.) seems to- be 

 underlain with clay. A mile and a half northwest of the south 

 end of Hook mountain the Rockaway river has cut through a 

 thin coating of glacial sand and gravel into underlying clay. Ex- 

 tensive deposits are said to occur on the property of J. B. Rick- 

 etts, near Parsippany. In the vicinity of Little Falls, Singac 

 and Mountain View there are extensive areas — at low levels — 

 underlain by clay which is dug at a number of points, Plate XVI. 

 In places the laminated clay is overlain by till, some of which is 

 not too stony to be used also for brick; elsewhere by stratified 

 sand and gravel. Clay also, underlies the low ground northward 

 from Mountain View nearly to Preakness, but it is deeply buried 

 by sand and silt, except along the borders. 



The clay at the lower levels is always finely laminated, the thin 

 clay laminae being separated by fine sandy partings. It is cal- 

 careous and frequently contains concretions of carbonate of lime, 

 some of which are shown on Plate IV (p. 24). These are 

 very abundant in certain layers, occurring in clumps at certain 



9 a g 



