GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I47 



I^icd by that formation. We have no observations respecting the dip of 

 the strata here. The occurrence of a remnant of the floor beneath the 

 granite in the valley reminds us of what has been said jDreviously (p. 

 126) concerning a similar state of things in the lower part of the valley 

 of Mt. Washington river. 



The high ridge between Rocky branch and Razor brook shows the 

 Conway granite throughout, both on the surface and on the precipitous 

 southern slope facing Saco river. The section passes next up the east 

 side of Hart's mountain, and no exploration has been made there to de- 

 termine the precise boundary between the granite and the highly-inclined 

 White Mountain schists. The section now crosses one of the larger 

 areas of the White Mountain group, concerning which ample details 

 have been presented upon a previous page. 



The next rock over the southerly flank of Mt. Lowell and the top of 

 Mt. Carrigain consists of porphyry. No outcrops show themselves for 

 two miles west of Duck Pond brook on the section line ; and this is the 

 proper horizon for the recurrence of either the Conway or Albany gran- 

 ites, before coming to the porphyritic series. These latter rocks are of a 

 reddish cast, the crystals being of a deeper shade than the homogeneous 

 base. Jointed planes dip towards Mt. Carrigain. The porphyries upon 

 the east slope of Carrigain are finer grained, more slate-like in color, and 

 dip at first towards Mt. Lowell. Higher up they begin to dip into the 

 mountain. Whether these planes are to be regarded as those of deposi- 

 tion, remains to be seen. On the summit of Carrigain the rock is a 

 peculiar speckled porphyry, reciuiring further examination for specific 

 description. On the west side the descent is quite steep, and the planes 

 constantly vary in position, as if representing numerous small folds in 

 the stratification. The talus is more abundant here than on the east 

 side, though not equal to that on the south side of Mt. Lowell. 



Our delineation of this section (Fig. 15) brings in the porphyritic 

 gneiss at the south base of Mt. Carrigain, in the deep valley of Sawyer's 

 river, so as to show the mutual relations of all these formations. Mt. 

 Hancock on the west is composed of the ordinary Conway granite. Next 

 we will introduce a sketch of the rocks south of the Saco river, chiefly in 

 the town of Albany, as these come next in order. As a matter of con- 

 venience the porphyries and breccias in that area are described. There 



