52 



APPENDIX TO THOMPSON'S VERMONT. 



GRANITE BOULDERS. 



ROCKING STONES. 



TRAP AND PORPHYRY. 



tained of wliicli the State House was built. 

 Further south, in the counties of Windsor 

 and AVindham, there are many isohxted 

 patches of granite and gneis, but with the 

 exception of Ascutney mountain, they are 

 of quite limited extent. In numerous 

 places, granite is seen traversing the other 

 rocks, in the form of dikes, veins and 

 seams. This is particularly observable in 

 Marshfield and Woodbury ; and this fact, 

 and, also, the fact that fragments of clay 

 slate are there found, embedded in the 

 granite, make it certain that the granite 

 has been in a melted state since the forma- 

 tion of the slate. 



Granite boulders are scattered, more or 

 less abundantly, over the whole of this 

 division of the state. In the northeastern 

 part, they are exceedingly numerous, and 

 many of them are of very great magnitude. 

 From a single granite boulder, in Greens- 

 borough, the material for a good sized 

 stone house, including the walls of the 

 cellar, were obtained, without using it all. 

 Another isolated boulder in that town, is 

 41 feet long, 22 feet high, and, in the 

 widest part, 25 feet wide, and is calculated 

 to weigh more than a thousand tons. About 

 half a mile from this large boulder, there 

 are two smaller gi-anite boulders, aljout 80 

 feet apart, so nicely balanced, on other 

 granite rocks, as to be easily rocked by a 

 push with the hand, and hence they have 

 acquired the name oi the rorkimx stones. 



layers of black mica, separated from each 

 other by extremely thin layers of pure 

 white quartz. In some portions of this 

 granite the balls, or nodules, constitute 

 quite one-half of the entire mass, ivhile, in 

 other portions, they are scattered very 

 sparingly, often several inches asunder, in 

 all directions. The only locality, beside 

 those just mentioned, where this grauite 

 is found in place, is just over the north 

 line of Vermont, in Stanstead, C. E. Boul- 

 ders of it are scattered, sparingly, over a 

 great part of the surface of the counties of 

 Orleans and Caledonia. 



The serpentine has been already men- 

 tioned in our account of the talcose division, 

 as occurring along the line of the gold for- 

 uiatiou. Some of those tracts are quite 

 extensive, forming hills of considerable 

 elevation. This is the case in Cavendish, 

 Lowell and Troy. In the serpentine in 

 Lowell, fine specimens of asbestus and of 

 diiferent varieties of amianthus, arc com- 

 mon. In Troy, it contains a lai'ge irregular 

 bed (ir vein of iron ore. The ore appears 

 well, and extensive works were erected for 

 manufacturing it into iron ; but tlie diffi- 

 culty of working it, on account of the 

 titanic acid it contains, and the cost of 

 transportation, rendered the business vm- 

 prolitable, and the works were, therefore, 

 abandoned and have gone to decay. The 

 following is the result of the analysis of this 

 titaniferous iron ore, by IMr. Olmsted : 

 Pei'oxide of iron, - - _ - 81.20 

 Protoxide " - - - - - 13.37 

 Titanic acid, - - _ - - 4.10 

 Silica, -------- 1.33 



Rocking Sluiies. 

 The accompanying rude cut will serve to 

 show their relative positions. They are 

 both considerably elevated above the sur- 

 rounding country. The one at the right 

 hand in the figure is U feet high, 12 feet 

 long, and weighs about 70 tons. It rests 

 upon another mass of granite about 16 feet 

 high. The other rockhig stone, at the left, 

 is 8 feet high and 11 long, Aveighing about 

 40 tons. 



The granite of this division, though 

 generally good, and, uuich of it, of a supe- 

 rior quality for building purposes, exhibits, 

 nevertheless, several varieties. Perhaps 

 the most remarkable of these, is that found 

 in place in Craftsbury and Northfield, and 

 which has, sometimes, been called JVvdular 

 Granite. The granite is of the ordinary 

 character, with the exception of having 

 flattened })alls of black mica, about one 

 inch in diameter, scattered through it, 

 like plums in a pudding. These balls, or 

 concretions, are composed of concentric 



100.00 

 Metalic iron, ----- 66.62 

 Chromic iron is also met with in many 

 places in the serpentine of this neighbor- 

 hood. In Jay, there are veins of it two 

 feet wide. The ore is of good quality, and 

 might easily be obtained to any amount. 

 Its analysis, hy 'Mv. Hunt, gave the follow- 

 ing result : 

 Green oxide of chromium, - - 49.90 

 Protoxide of iron, - - - - - 48.96 

 Alumina, with traces of silica, &c., 1.14 



100.00 

 One hundred parts of this oi-e will yield 

 191 parts of chromatc of lead, or chrome 

 yellow. 



Trap and Porphyry. 



These are found in Vermont only in the 

 form of dikes, or intrusive beds among the 

 other rocks. Trap dikes are met with in 

 all parts of the state, but they are much 

 more common in some pai'ts than in others. 



