1886.] NEW YORK ACADEMY OP SCIENCES. 221 



•of the older Archaean of the New Jersey and New York High- 

 lands. 



The Cranberry Iron Mine is located at the eastern end of this 

 railroad, and is inclosed in rocks similar to those above described. 

 It was formerly operated througli a long tunnel, but the ore is 

 now obtained in a great open cut 50x100 feet in area and 30 feet 

 in depth. Tiie ore body has been known for many years, and 

 ■loose surface rock was formerly smelted in an old forge, a 

 •mile and a half north of the present excavations; gun barrels 

 were made there during the Rebellion. The bed is of great ex- 

 •tent longitudinally, outcropping for several miles, according to 

 statements made by residents of the vicinity. Its thick- 

 ness at Cranberry is as yet unknown, but is at least 100 feet. 

 Work was begun in earnest about three years ago when the E. 

 T. & W. N. C. R, R. was constructed to afford cheap and con- 

 venient transportation for the ore. Under the charge of Mr. 

 Lumsden, a neat mining town has been built up and the enter- 

 prise appears prosperous. The ore is peculiar in being self-flux- 

 ing; no limestone is used in the furnace at Cranberry, which 

 makes about 7^ tons of pig iron per day, using 15 tons of ore. 

 Formerly, blue limestone was brought in from Elizabethtown, but 

 it was found that better iron was obtained without the flux, and 

 the practice was abandoned. This self-fluxing property appears 

 ■to be the result of the presence of dark-colored pyroxene, which 

 is extremely abundant. The ore proper is a moderately coarse, 

 poorly crystalline magnetite. Some epidote is associated, and 

 insignificant amounts of white quartz and calcite. There are 

 some bands of feldspathic rock. The inclosing strata are gran- 

 iulite and hornblendic granulite. I could find no mica in either 

 ■ore or rock. Near the open cut a decomposed granulite gave 

 strike N. 30° E., dip 45° N. W. This may not be the direction 

 of the ore body, however, for the strata are much contorted. 

 The rocks are decomposed to a great depth; along the railroad 

 the cuts have exposed the granulites to a depth of 60 feet, and 

 they are rotten to the rails; I was unable to ascertain how deep 

 this decay extends. It appears to be much more extensive than 

 ■in the similar rocks south of the moraine in New Jersey and 

 Pennsylvania, and is, perhaps, mainly due to the higher annual 

 temperature. Near the mine the railroad has been cut through 

 a great trap dyke. This rock, apparently a diabase, does not 

 weather into the clay yielded by the granulites, but decays in 

 moderately large pieces, some of which are of spheroidal form. 



The great decomposition of the rocks noted above greatly ob- 

 scures the character of the underlying strata. Except along the 

 streams, or in artificial excavations, exposures are rarely found. 

 Almost the whole of Roan Mountain is obscured by the thick 



