Kemp — Geology oe Essex County. 



is of mild relief. Along the east and south there are the spurs of Mount 

 Whiteface, and further west the ridge of Moose Pond mountain, all forming 

 a practically unbroken wilderness. The mapping of this section is tentative 

 and is based on the inference that the rocks in the edges of these ridges as 

 met in North Elba on the south and Whiteface on the east continue toward 

 the north, but where the line, if indeed it can be made out, between the rocks 

 of Series I and Series III is to be drawn, must be investigated later. A 

 high ridge bounds the Saranac river on the west, south of Bloomingdale, 

 and another appears north of the river and east of this town. 



Series I. At No. 51a there is a red orthoclase gneiss. At Nos. 52a and 

 52 the gneiss is dark green, and is the same as No. 2 of the Jay map. Under 

 the microscope it exhibits microperthitic orthoclase, a little plagioclase, and 

 some almost opaque hornblende. Zircons are also not lacking. At the 

 bridge over the Saranac there is an excellent exposure (No. 52). Outside the 

 township, in Franklin county, the gneiss rocks continue beyond Franklin 

 Falls, and two miles down the river there is a goodly ledge of the familiar 

 white, crystalline limestone, charged with pyroxenes, titanites, bunches of 

 hornblende, pyroxene and quartz. The dark hornblendic schists that always 

 accompany the limestone, are also well developed. All these indicate that 

 the anorthosites and gabbros, so far as present, lie south of the Saranac river 

 in this town, although we know that the)' exist near St. Regis lake to the 

 west of the line of Essex county. The strike of the gneisses is mostly north- 

 east, but east and west and northwest strikes are known. 



Series II is not met within the limits of the town, although, as stated 

 above under Series I, it does appear about three miles north of the line. 



Series III. The area covered by these rocks is mapped on an inferential 

 basis from observations on the prolongation of the ridges south and southeast. 

 While actual study of the rocks in situ may modify this, I consider the 

 inference as worthy of confidence in the present state of our knowledge. 



Series IV is entirely lacking. 



Series V. No dikes were noted in the town itself, but just over the 

 border at Franklin Falls one appears in the side of the road near the hotel, 

 with a northeast strike. It is a dark trap, presumably diabase. 



Series VI. The modified drift is widely spread in the less elevated 

 districts. In the northeastern corner it covers several square miles so that no 

 outcrops are available. Level meadows suggest at times former ponds or 

 lakes, and the extended one near Bloomingdale station, outside the county, 

 was referred to in my former report, page 472. 



