260 J. F. KEMP — ROCKS OF THE EASTERN ADIRONDACKS. 



While the writer does not hold these views for the large exposures de- 

 scribed above, there are some exposures of a small character that seem 

 clearly referable to this method of origin. 



Immediately south of the village of Crown Point is the old eupyrchroite 

 (apatite) locality described by Emmons, where the attempt was made to 

 mine apatite^ and where much crystalline granular calcite occurs of a 

 variety very like the true limestone. It is in heavy bedded gneisses, 

 apparently along a fault-line, and cannot be of more than very limited 

 width. The old graphite mines in Ticonderoga township are based on a 

 very long fissure-vein, which cuts the banding of gneisses at right angles 

 and is filled with much pegmatitic matter, as well as with crystalline 

 calcite. 



A vein occurs in the anorthosite in northern Willsboro, in the cuts of 

 the Delaware and Hudson railroad.f There is also an included mass of 

 ophicalcites in the anorthosite in the same series of railway cuts. The 

 most interesting vein of all is at Cascadeville, a summer hotel on Edwards 

 ponds or Long pond, as the lake was formerly called (they are now 

 called the Cascade lakes), about five miles west of Keene Center, on the 

 road to North Elba. The lake was originally a continuous, elongated 

 body of water, lying in one of the common faulted passes of the moun- 

 tains and at the top of a divide. It is a type which, in the report to Pro- 

 fessor Hall, the writer has spoken of as " fault-lakes," and which is very 

 wide spread in this region. Such lakes lie between steep cliff's in the 

 passes of the mountains and at the headwaters of a divide. Almost all 

 the passes of this character are provided with them, and in the report 

 above referred to many instances are cited. Long Pond mountain, a pre- 

 cipitous cliff, lies on the north side of the Cascade lakes. An avalanche 

 has come down its face, leaving a narrow gulch and dividing the old 

 lake into the present two. This slide exposed a body of lean iron ore 

 200 or 300 feet above the water alongside the first cascade. From the 

 ore-body a narrow belt of crystalline calcite, from 8 to 10 feet across, 

 extends from 1,000 to 1,500 feet and more to the south. It is thickly 

 charged with very beautiful coccolite and black garnets. Emmons men- 

 tions scapolite also. Two trap-dikes cut the limestone and have served 

 to divert the stream along themselves for a part of its course, they fur- 

 nishing, as is so frequently the case in the mountains, the easy line of 

 erosion.J The walls of the limestone are typical anorthosite. 



* See W. P. Blake : A contribution to the early history of the industry of phosphate of lime in this 

 country. Baltimore meeting Am. Inst. Min. Eng., vol. xxi, p. 157. Blake describes the eupyrchro- 

 ite as on the contact with a dike of greenstone. There is also a green chloritic rock with abun- 

 dant and at times handsome brown tourmalines in it. 



fT. G. White: Geology of Kssex and Willsboro townships, Essex county, New York. Trans. 

 N. Y. Acad. Sei., vol. xiii, p. 218. 



JAlthough the writer has visited the locality he is indebted for still more extended observations 

 to Dr N. L. Britton. 



