Granite at Mounts Adam and Eve. 645 



scapolite. Some even more complex a<^gTegates will be mentioned 

 in the detailed notes that follow. Chondrodite, at times, thickly 

 charges the limestone, and with it is spinel. These contacts have 

 been the fruitful source of the many interesting minerals that have 

 come from this region in the past. One of the best contacts is seen 

 along- the southern prolongation of Mt. Eve on the farm of Mr. 

 Onderdonk. The limestone, thickly charged with dark silicates, 

 resembles the franklinite ore of New Jersey, and has excited some 

 unwarranted local hopes. The silicates are chiefly the characteristic 

 brownish-green hornblende, dark yellowish-brown biotite, titanite, 

 and faint green pyroxene. The granite outcrops at a short distance 

 on the land of Mr. James Hedges. North of the highway the lime- 

 stone and the granite are in actual contact. The former shows 

 coarsely crystalline calcite and phlogopite; the latter light green 

 pyroxene and scapolite. Fifteen feet from the contact the granite 

 consists of quartz, microcline, and green pyroxene. 



A fine exposure occurs near the old boarding-house formerly used 

 by the hands of the Mt. Adam quarry. This limestone lies between 

 Mt. Adam and Mt. Eve, so that it has been in a ver}^ favorable 

 situation for alteration. North of the boarding-house the limestone 

 is surcharged with streaks of silicates. These consist chiefly of the 

 greenish-brown hornblende characteristic of the contacts. Its pleo- 

 chroism is very light yellow, parallel n; faint yellowish-brown, 

 parallel b; faint bluish-green, parallel c. It forms large, irregular 

 crystals in the slide with an extinction of 20°. Closely involved 

 with it is clear green pyroxene, while the remainder. of the slide (13) 

 is scapolite. This mixture, with some additions and variations, we 

 find quite invariably along these contacts. The nearest outcrop of 

 granitic rock, back of the boarding-house and about 50 yards away, is 

 a quartz diorite (slide 14) with quartz, plagioclase, dirty brown horn- 

 blende, titanite, and little if any orthoclase. A little way south of 

 the barracks a ledge has been blasted. It proved to contain (slide 15) 

 microcline, light green, monoclinic pyroxene and titanite, and to be 

 much like 11. One-eighth of a mile south of Mt. Adam the high- 

 way crosses the contact. The limestone contains bunches of coarsely 

 crystalline, dark biotite a foot or more through (spec. 27), while 

 the granite four feet distant consists of the usual mixture of green 

 pyroxene and scapolite (slide 28). On the southwest side of Mt. 

 Adam one of the most interesting sections of all is afforded. It is 

 illustrated by the accompanying Figure 1. Leaving Mt. Adam a 



