GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 33 



removed is a granitic aggregate, very siliceous, like the exposures in the 

 Silver cascade and elsewhere in the White Mountain Notch. The flume 

 exists because of the removal of this dyke, twenty-five feet in width. 

 The vertical joints of the walls have the direction of N. 62° E. It is 

 well known to tourists, and has been figured in Oakes's work on scenery. 

 Half a mile up the stream the rock is micaceous quartzite. The speci- 

 mens brought from various localities higher up, the last mile and a half 

 east of Nancy's pond, are gneissic (Nos. 310, 311, 313). At Bemis sta- 

 tion a dark rock appears, with the same general position as the strata at 

 the saw-mill. A comparison of those already mentioned as coming from 

 Mt. Hope, the ridge south, Nancy's brook, and Bemis station, with the 

 rocks of Mt. Webster and the lower part of Mt. Washington river, proves 

 them to be identical in appearance and composition. 



Below Bemis this rock may extend nearly to Sawyer's river. At the 

 most prominent bend in the Saco, about a mile and a quarter below 

 Nancy's brook, some large ledges dip 75° N. 73° W., with many contor- 

 tions. In the sai^Tie neighborhood the railroad has uncovered a ledge 

 dipping N. 80'' W. Dr. Bemis says there is a slaty rock of this descrip- 

 tion on Half-way brook, higher up the mountain. Duck Pond mountain 

 is supposed to be composed of the same materials, as I found ledges of a 

 gneiss with much silica in it about a mile above Sawyer's river, on Duck 

 pond, dipping 80° S. 60^ W. Three fourths of a mile farther north-west 

 the same rock occurs. Scarcely anything can be said respecting the 

 areas west of Mts. Chocorua and Passaconnaway. Both show a high 

 westerly dip. The first is clearly the ordinary schist of this series. The 

 specimen from the other locality is a somewhat ferruginous micaceous 

 quartzite. 



In the report for 1871 it is stated that there is an outcrop of this 

 formation upon the head waters of Little Deer brook in Albany. Our 

 specimens from this locality very closely resemble the schist commonly 

 characterizing this group. The outcrop is quite limited, lying between 

 feldspathic porphyry and feldspathic breccia. Another small area has 

 been discovered upon Rocky Branch in Bartlett. 



Peinigcwasset River area. The assemblage of gneisses and granites at 

 the Georgianna falls in Lincoln may possibly belong to this series, though 

 noticed under the Franconia breccia. It is probable that the Montalban 



