388 CONGLOMERATE. 



graphically from the azoic talcosc schist. Lithologically, the two talcosc schists cannot 

 be distinguished from each other ; and the want of magnesia is probably common to both. 

 The belt is. mostly composed of talcose schist in Starksboro, llinesburgh, Fail-field, and 

 Sheldon. In the other towns the other varieties predominate. The towns where the tal- 

 cose schist predominates have not been examined as carefully as the others ; hence we 

 conjecture that when they are carefully studied, the amount of talcose schist will be di- 

 minished. We must, however, except a section across the south part of Hinesburgh, upon 

 a branch of Lewis Creek. The rock there is wholly composed of talcose schists and grits. 



TVo<* 9 9 9 9 9 9 9 10 f n 10 II + 11 11 11 18 12 18 

 JS - 138) 148! 143) 147) ISO) 154) 156) 1O8 HO) 884 ' 826) 828) 233) 134) 182) 183) 



represent this variety in the State Cabinet. Many specimens of talcose schist, when 

 weathered and smoothed by eroding agencies, display a number of small rolled grains of 

 quartz, etc., in its composition. This is a talcose sandstone ; and probably most of the 

 talcose schist of this belt is only an altered sandstone. 



The last named variety, the coarse conglomerate, is the characteristic rock of the group. 

 In general it may be called a coarse conglomerate cemented by talcose grit. Probably 

 the coarse conglomerates along the east border of the quartz rock, already described, in 

 Clarksburgh, Mass., in Sunderland, Peru, "Wallingford, Chittenden, Pittsford, and Lincoln, 

 belong to this group. We should have little hesitation in extending the color of the 

 talcose conglomerates along the east border of the quartz rock to the Massachusetts line, 

 only it would be very narrow. 



In Chittenden there are evidences of a large amount of conglomerates between the 

 quartz rock and gneiss ; and this district has not been explored, chiefly owing to the wild 

 nature of the country, and the difficulty of discovering ledges beneath the immense piles 

 of detritus. But ledges of a gneissoid conglomerate are numerous near the west line of 

 Chittenden, midway between the north and south villages. Bowlders of coarse conglom- 

 erate, similar to that in Richmond, are found in the north part of Chittenden. They 

 have a peculiar appearance, and must therefore have been derived from ledges in the 

 vicinity, rather than those known further north. 



In Lincoln the pebbles of this conglomerate vary in size, from grains of sand to pebbles 

 as large as hens' eggs. They are mostly blue hyaline quartz, whose original source is 

 unknown. It resembles the conglomerate in Wallingford. The next locality to the north 

 that we have explored, is in the west part of Richmond, extending over the town line 

 to Jericho, Williston, and Essex. The pebbles are generally about three inches in diam- 

 eter, and never exceed six. They are granite, a fine-grained variety, evidently derived 

 from Laurentian rocks, quartz rock, dolomite, and silicious limestone. There is nothing 

 about the pebbles by which the age of the conglomerate can be determined with certainty, 

 though there is a strong resemblance between the limestone pebbles and certain beds of 

 limestone in situ, near Burlington. Sec Nos. ^5 to j4^, etc., in the Cabinet. 



In Fairfax there are pebbles of clay slate in a similar conglomerate, which were probably 

 derived from the Georgia slate. In the northwest part of Fairfax this conglomerate is 

 developed more finely than at any other locality, and it is there interstratified with quartz 

 rock. The pebbles are generally of the same size as those in Richmond, though some of 

 the fragments of slate may be a foot long. They are granite, quartz rock, talcose schist 

 and clay slate of every variety. The cement is sandstone, filled with so many crystals of 



