GEOLOGY OF TIIK LAKE DLSIKICT. 595 



Pine mountain. The line of junction l)ctwcen the j;neiss and sicnite is a 

 perpendicular seam running cast and west. The dip of the gneiss is east. 

 The gneiss occupies the lower ground, the sienite the hills adjacent. 

 There is a possible additional locality of this rock in New Durham. 



The most remarkable feature of this range is its singular double curva- 

 ture. So far as our observations extend, it seems to be a real bending of 

 the strata, rather than an accidental uncovering of an older unconformable 

 formation by the abrasion of the superincumbent groups. The latter 

 have been involved in the bending and overturning, and it is a significant 

 fact that the Lake gneiss within the folds of the hook d(jcs not come up 

 again on the west side in Ashland. Were the fan-shaped stratification 

 along Section VI a synclinal, as a slight examination might suggest, then 

 the Lake gneiss should reappear in the Pemigewasset valley. That it 

 does not, confirms the truth of our theory that the porphyritic gneiss is 

 the oldest. 



3. Lake Winniimsko(;i;e Gneiss. 



This formation has been so well defined already that it is unnecessary 

 to speak of its particular character in the region where it was first recog- 

 nized. It has stratification not easily recognized, occupies low ground, 

 occurs in embossed ledge.s, .showing stria; wherever disintegration has not 

 been too rapid, and is traversed by numerous segregated veins. These 

 features are suggestive of Laurentian age. I have in the first chapter 

 called the formation "Atlantic," signifying a period intermediate between 

 the Laurentian and Iluronian. I shall not find fault with any who seek 

 to refer it to a still older period. The general course of the area occupied 

 by this gneiss is north-west and south-east, and it corresponds very 

 nearly with the direction of Lake Winnipiseogee. There is a branch on 

 the west, leading southerly to Meredith, and a widening of the territory 

 occupied at the Maine boundary line. The extreme length of the area is 

 thirty miles; average, twenty-two and one half; average width, eleven : 

 total dimensions in square miles, about two hundred and sixty. The fol- 

 lowing are our principal observations respecting the position of strata: 



Sandwich. Between North and Centre villages, many 



At A. Y. Irving's, beyond North Sand- ledges on both roads, usually vertical, 



wich. with strike N. 60° E. 



