coos AND ESSEX DISTRICT. 69 



little mica and are wrought with facility, are applied. The area of this 

 rock is limited, being confined to the point of land between Sims stream 

 and the Connecticut. In Columbia, south of Sims stream, the high 

 point of land that is so noticeable just before we cross that stream going 

 south, is composed of sienite, but it is of a very dark color, either from 

 its being colored with manganese, or from the decomposition of the feld- 

 spar. On the side towards the stream numerous boulders have been 

 detached, and the angular blocks lie on the steep hillside ; some of them 

 are so poised that apparently only a slight force is needed to send them 

 to the bottom of the valley. It seems quite probable that this mountain 

 mass south of Sims stream was once connected with Mt. Monadnock, on 

 the west side of the Connecticut, possibly with that north, and that the 

 intervening rock has been worn away. This seems more probable, since 

 this area of sienitic rocks, including those north and south of Sims 

 stream and Mt. Monadnock, are surrounded by schistose rocks. To the 

 south-east in Stratford we find a rock similar to that south of Sims 

 stream, largely developed. The summit of Sugar Loaf mountain is a 

 solid mass of rock two or three hundred feet in length and half as wide, 

 and so precipitous that there are two or three places only where it is 

 possible to reach the summit. Specimens of the rock from this moun- 

 tain can hardly be distinguished from those south of Sims stream. 

 South-east, but still in the town of Stratford, we come to Percy peaks. 

 The rock here differs somewhat from that of the localities just de- 

 scribed. The feldspar is more of a flesh-color, is not so abundant, and 

 also contains some black mica and a smaller proportion of hornblende. 

 It also contains quartz, and besides, what is quite uncommon, the 

 quartz is frequently crystallized; and, though generally distributed equally 

 through the mass of the rock, crystals of smoky quartz have been found 

 having a diameter of six inches. These peaks, so symmetrical in their 

 outline, with their bare, white summits, form a marked feature in the 

 scenery. In Stark, approaching the railway station either from the east 

 or west, the mountain ridges project by each other so that there seems 

 to be an impassable barrier. On the south is Mill mountain, and on the 

 north there is a precipitous mountain bluff known as the Devil's Slide. 

 These rocks are separated from the granitic region northward by a band 

 of schist. The rock of the Devil's Slide is chiefly sienite, but it is unlike 



