GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. II9 



subordinate curve dipping N. 8y° E. This feature is like that ah'eady 

 mentioned in the rock near No. 30. 



At the fifth mile-post, where the road reaches its most southern limit, 

 there are more undulations in the strata, of which perhaps the average 

 inclination may be estimated as 15° N. 87° E. That their appearance 

 may be properly understood, the reader is referred to the two annexed 

 heliotypes taken of ledges at or very near the fifth mile-post. The bends 

 are perhaps zigzags rather than curves, but they represent the character- 

 istic forms of these phenomena in this portion of the section. This is 

 the andalusite mica schist of the Montalban series, which commenced a 

 short distance above the limit of trees, and continues to the summit as 

 well as to Ammonoosuc on the west side of the mountain. A few rods 

 above the fifth mile-post the dip varies from 75° to 90° N. Sy° E. (No. 

 43). F^ifty rods farther the dip is 75° in the same direction. No. 44, at 

 nearly five and a half miles, comes from strata dipping 50°-6o° N. 73° 

 W. No. 46 comes from a sharp angle in the road overlooking the Great 

 gulf, where the dip is 55° S. 33° E., on a ledge one hundred and fifty feet 

 long. A rocky knob rises on the south side of the road, just at the lower 

 edge of a sedgy plat, on which the dip is 25°-40° S. 23° E. (No. 47).. Ten 

 rods north of mile-post No. 7 the dip is 55° S. 87° W. (No. 48). At the 

 mile-post the dip is 50° westerly; and in certain granitic veins the feld- 

 spar is abundant. On a hummock near the summit the dip is 20° N. 48° 

 W. Standing east of the hotel, on the summit, one sees a hill to the 

 right of the road, above the head waters of the Ellis river, where the 

 strata apparently dip about 60° easterly. On the very summit the dip is 

 25° north-westerly. Just behind the Tip-top house the dip is S. 23° E. 

 On a spur towards the Lakes of the Clouds the dip is 60° S. 47° W. 

 Thus there is considerable variation in the dip at the very summit, a 

 .small synclinal eighty feet long showing itself at the highest part of the 

 mountain. The rocks are coarse and fine feldspathic mica schists, with 

 andalusite, beds of granite containing tourmaline, and veins of white 

 vitreous quartz. One specimen shows staurolite. 



On the west side, follov^ing down the railway, less pains have been 

 taken in observations of the positions, and the ledges are few. The dip 

 is thought to be essentially like that on the summit all the way to Jacob's 

 Ladder. A short distance below the Ladder, in a railway cut, the rock 



