GEOLOGY OF THE LAKE DISTRICT. 60I 



nous bands. Across the north part of this town, and the north of Tam- 

 worth, no ledges appear, everythhig being covered by drift. Since the 

 preparation of Plate XII I have thought best to connect this North 

 Sandwich area with the outcrops on the Chocorua range (p. 133), elimi- 

 nating the intermediate granite, thus located in consequence of a mis- 

 understanding. This gives us an area twelve miles long and from two to 

 three wide, possibly isolated from connection with the principal part of 

 the formation. We can easily understand that this may consist of a folded 

 synclinal, separated from the Tamworth exposure by an inverted anti- 

 clinal. At L. C. Clark's, andalusite is present in the ledge, and there are 

 two small trap dykes. On Stevenson's hill, in Tamworth, the rocks are 

 indefinite, — granitic, gneissic, and ferruginous. At T. Perkins's, north of 

 the Iron Works, is a coarse granite vein. Between the two Tamworth 

 villages are gneissic outcrops, whose dips are not recorded. At W. 

 Cushing's, the ledges are mostly of the granitic varieties. The east part 

 of Tamworth and the west part of Madison abound in high, isolated hills, 

 mostly of a granitic variety of the Montalban series, where stratified 

 planes are scarcely recognizable, yet the Montalban character of the 

 material is evident. Chatman hill contains much coarse, indigenous 

 granite. At J. Lyman's, on the south-west side of Hedgehog hill, Madi- 

 son, is a granitic gneiss. Pine hill is probably composed of the same 

 material. There is a granitic rock at N. Snell's, in Tamworth, nearly two 

 miles west. The same, with ferruginous rock and trap, is repeated at 

 the school-house on the north-east corner of the town. The hill south- 

 west from Whitton pond, in Madison, is composed of Concord granite, 

 with jointed seams dipping 60° N. W. The north-west side of this hill is 

 precipitous. The hill a mile and a half east of this is thought to be com- 

 posed of similar material. 



The east part of Madison is separated by a broad valley from the west, 

 just considered ; and the stratified schists take the place of the Concord 

 granites. Very few observations have been made in this region. At L, 

 Long's and farther to the east the strata are variable. Some of the finer- 

 grained mica schists are traversed by segregated veins, and weather like 

 the siliceous limestones of eastern Vermont. The usual dip through the 

 town of Eaton is 5o°-6o° W. The rock at the old lead mine in Madison, 

 formerly Eaton, is largely composed of silica. On the east side of White's 

 VOL. II. ^6 



