320 BANGE AND EXTENT. 



this belt : for there we find an exposure of a red sandstone, which we have hesitatingly 

 referred to the red sandstone series. Several layers of sandstone are also found in the 

 clay slate to the west of Stacy's. 



The slate thins out rapidly as we approach Orwell. It passes west of the village in 

 such an inferior development as to be recognized with difficulty. It thickens, however, 

 to the northward, but the distinct argillaceous character has become greatly obscured by 

 the incorporation of more or less of the carbonate of lime into its composition. West of 

 Shoreham village, there are ledges extending over a width of at least half a mile, that 

 are comparatively free from lime. The two varieties interstratified with each other 

 pass to Bridport, and show themselves a little east of the village and there are 

 developed along a direct line to Snake Mountain. Because of the great imperfection of 

 all maps, one might be led to suppose that the amount of this slate at Snake Mountain 

 is unusually small, because it narrows to this point so greatly. But it is of uniform 

 thickness from Shoreham to Charlotte, and the narrower the surface that is covered, the 

 steeper is the hill upon which it crops out. At Snake Mountain, for example, the whole 

 surface of the Hudson River slate is very steep, insomuch that it can hardly be used for 

 pasturage. Fig. 167 illustrates this position. 



The range curves eastward from this mountain, and shows itself where the town line of 

 Addison intersects Otter Creek. It is found all along the steep, west side of the range of 

 hills running through Waltham. As soon as it enters Ferrisburgh it is concealed beneath 

 the soil, as indeed are all the adjacent rocks, as they cross the valley in which the R. 

 and B. R. R. passes to New Haven. In Ferrisburgh it appears on the west side of 

 Marsh Hill, Shell House Mountain, and Mount Fuller. At the mills in the northeast 

 corner of the town it is very conspicuous. In Charlotte the slate appears on the west 

 side of the same range of hills, viz ; Mount Philo, Pease Hill, and Mutton Hill. To 

 the north it spreads out over more of the surface, covering the whole of Pottier's Point 

 in Shelburne. 



Perhaps it may include Rock Dunder, though that rock is described under Utica slate, 

 there being no fossils found in it to determine its age. Between Lonerock and Appletree 

 Points in Burlington, it re-appears after a bath in the lake, and proceeds north across 

 Colchester Point. To the north it occupies the bed of the lake between the Hero Islands 

 and the coast of Franklin County. The edges of Milton and Georgia are barely touched by 

 it the whole distance. The islands are made of this slate, whenever they are not composed 

 of clay or sand. They are Gull Island, Fish Bladder Island, Savage's Island (where 

 explorations have been made for roofing slate), Welden's Island, Potter's Island, Ram 

 Island, and the other small island in St. Albans Bay, Wood's Island, Knight's Island, 

 Butler's Island, Diadama's Island, Hen Island, and Hog Island in Swanton, most; of 

 which is properly a delta of Missisco River. 



Upon the main land in Franklin Co., beginning at St. Albans, this slate continues to 

 increase in width as far as Swanton. It is the widest at Rich's quarry, in the south part 

 of the town. It is well shown upon the banks of Missisco River at Swanton Falls, and 

 at Mr. Clark's house'a mile or so west of the village. In this vicinity it divides, the 

 greater part passing to the west of the Trenton limestone at Highgate Springs. East of 

 the springs there is a wide plain upon which no rock is seen, which is the place for the 



