646 



Granite at Mounts Adam and Eve. 



swampy stretch is first passed, and then a ledge of coarsely crystal- 

 line white limestone is met, which is charged with great masses of 

 red chondrodite, up to two inches in diameter. Beyond this granite 

 appears, and then the usual scapolite zone. This last is very coarsely 



60ydj,>< IQQ yis. 



Fig-. 1. — Section from the Southwest side of Mt. Adam — Northwest toward the 

 Drowned Lands. The tree is a lone butternut, 



crystalline and contains fine prisms of scapolite, in cavities, due 

 probably to the solution and removal of calcite. We found them up 

 to two inches in diameter, and well terminated. Prisms of pyrox- 

 ene are all through the scapolite, often -J to | of an inch in diame- 

 ter, and having the usual eight faces of the prism zone. Titanites 

 too of large size appear, showing OP, — P, and oo P. Doubtless some 

 rarer minerals could be found by searching, but the three mentioned 

 are by far the commonest. Beyond the scapolite lies coarse white 

 limestone, which runs under gravel until all flatten down beneath the 

 old lake bottom of the Drowned Lands.^ In a quarry on the Miller 

 farm, which lies on the east side of Mt. Eve, along the line of sec- 

 tion 2 (Fig. 1), an interesting contact appears. The usual zone of 

 pyroxene and scapolite is well developed, and in the limestone are 

 many bunches of silicates, etc. In the thin sections phlogopite is 

 abundant, and chondrodite with spinel and fluorite is well developed. 

 The chondrodite with its honey-yellow to colorless pleochroism fur- 

 nishes a very beautiful mineral. It lacks crystal boundaries as is 

 usual along this belt of limestone. In one section a fine twin was 



1 This old lake bottom is a most interesting topographical study, and is as 

 fine an illustration of sucli phenomena as could be desired. For miles along 

 the Walkill River it forms a lev-el, more or less swampy stretch, above which 

 some hills project known as "islands." Such are Big Island, Pine Island, 

 etc. The land is now pretty well drained and devoted to raising onions. The 

 workmen engaged in the early drainage ditches suflFered from some peculiar 

 malarial fevers. (See, "An Account of the Fever which lately prevailed in 

 the Drowned Lands in Orange Co., N. Y., by Dr. D. R. Arnell, Amer. Med. 

 and Phil. Register, II, 8, 1822.) 



