coos AND ESSEX DISTRICT. 89 



liar in being composed chiefly of quartz and a dark, rusty brown mica. 

 In the lake there is a diatomaceous earth ; and on its western shore is a 

 mica schist, the strata of wdiich are nearly vertical, but generally the dip 

 is from 75° to 80° easterly. The hill between the lake and the Andros- 

 coggin is 244 feet above the former. In one specimen from the eastern 

 slope of this hill we noticed a trace of copper, Bragg's bay is fifty feet 

 lower than the lake ; and west of the bay the strata are still more nearly 

 perpendicular, and a mile west they dip westerly, and the mica schist here 

 contains garnets. Passing the height of land, and descending towards 

 the Millsfield ponds, on this slope we still find mica schist; but three 

 fourths of a mile east of the ponds there is an argillaceous schist, which 

 has an easterly dip, as, also, the mica schist found on either side of it. 

 The hills south-west of Millsfield pond are mica schist ; but the strata 

 seem to have been more disturbed than elsewhere on the section, as we 

 found that the strata dip to the south-east and south. Succeeding this 

 schist on the west, and forming a high mountain ridge on the border 

 of Millsfield, there is a granitic rock, probably a granitoid gneiss. It 

 is composed of a light-colored feldspar, a light gray quartz, and a small 

 proportion of mica. 



Leaving the ridge, we descend into the valley of Phillips brook, where 

 there is a considerable space, nearly level, covered with drift. Passing 

 over the height of land west of this brook we come to the head waters 

 of Nash stream ; then we pass three apparently parallel ridges, all com- 

 posed of granite. The rock is fine-grained, of even texture, is compact, 

 rather tough, and it differs from the last in that the feldspar is of a light 

 flesh-color. Between the branches of Nash stream and Lyman brook 

 we find, at the height of land, a coarse granitic rock, and it is undoubt- 

 edly intrusive. On the western slope of this ridge there was not seen a 

 single outcrop of rock for a mile and a half ; but on Lyman brook, a little 

 more than half a mile above the last saw-mill, there is a coarse granite, 

 but it differs from the last in being very much jointed; sometimes the 

 fragments are not more than three or four inches through. Farther west 

 this peculiar jointed structure was not seen; but the granite is massive, 

 is very coarse, and is composed mostly of quartz and feldspar, but it 

 has also a very little black mica. West of the granite, at W. Kimball's, 

 the mica schist begins, and extends on the line of the section to the 

 VOL. II. 12 



