254 SURFACE GEOLOGY, 



found in the east part of the town, and two boulders of andakisite schist, 

 with coarse and fine crystals, one of them apparently from Carr's moun- 

 tain. These specimens ornament the grounds of the institute, while 

 other minerals are exhibited under glass. 



In order to give some idea of the distribution of boulders in the state, 

 I will select a few examples, and describe carefully the kinds of rock 

 found, their size, probable origin, and distance of transportation. In the 

 same connection, other interesting features illustrating the general sub- 

 ject may be mentioned incidentally. Some generalizations may follow 

 the description of localities. 



Boar's Head. 



In the middle of Hampton Beach, a mound of drift about 1300 feet 

 long and 45 feet high, rises very conspicuously to view. It is the well 

 known Great Boar s Head, visited every summer by thousands of people 

 for the enjoyment of sea air and bathing. Though small, it may be re- 

 garded as a true lenticular moraine, isolated from all visible connection 

 with any other mass of till, by a distance of nearly two miles between the 

 nearest points. It has been exposed to the wearing action of the sea 

 from time immemorial, and consequently has lost a considerable portion 

 of its mass. The clayey portion of the till is washed out, leaving the 

 stones, and consequently the former size and shape of the mound is 

 clearly indicated at low tide by the remnants. From the extreme point 

 of the cliff these boulders extend south-east for 400 feet. Their northern 

 limit is about a quarter of a mile north of the Boar's Head hotel; opposite 

 the middle of the cliff the boulders are continuous 120 feet to the fucus 

 growth, and a single stone projects out of the water as far again. If the 

 hill were restored to its original dimensions, it would probably be 1800 

 feet in length by 350 in width, with a course about N, 35° W, It was 

 steepest on the south side, Mr. S. H. Dumas, the proprietor of the hotel, 

 thinks there has been no wearing away of the hill of any consequence 

 for many years. The landing-place for boats on the south side has been 

 constructed as it is now for the past forty years. If a new one were 

 desired, no change of position would be required ; so that the erosion 

 on that side has been very inconsiderable. The present slight curve in 

 the beach north of the hotel he remembers to have been straight once. 



