546 MAGNESIAN KOCKS. 



range is evidently composed of two ranges in Warren, and in Watorbury, independently 

 of the repetition from the eastern part of the formation. The two great ranges in Orleans 

 county are probably the same bed upon the opposite sides of an axis which is regarded 

 as an anticlinal by Logan, but a synclinal by Prof. Adams and by Rev. S. R. Hall. 



Upon the west side of the Green Mountains, all the beds may be referred to one band, 

 except those in Berkshire. But they undoubtedly are the same, as the strata in Richford 

 are repeated in Berkshire by a synclinal axis. 



4. The gneiss of the Green Mountains. But three beds of these magnesian rocks are 

 repeated in this formation ; and the existence of all these is problematical. But just 

 south of the bed in Readsboro are two beds in Rowe, Massachusetts, which belong to the 

 same geological age. These were probably formed at different epochs. Besides the bed in 

 Readsboro, Vermont, there is one in Bolton, and another, of serpentine, at Hazen's Notch, 

 in Westfield. 



It is not impossible but that there may be only one range of beds in the talcose schist 

 formation, and that the number of ranges now found in it show how many times the 

 strata have been folded. It is possible, also, that these beds may indicate the limits of 

 folded axes, provided that in the first place we can find an undisturbed region where their 

 true stratigraphical relations to each other can be determined. The Canada Survey find 

 two belts of magnesian rocks in the Quebec group, which is the prolongation of the talcose 

 schist group into Canada. They place an anticlinal in the Troy valley, another in the 

 Richford valley, and make great use of those beds of steatite and serpentine in studying 

 the stratigraphical order of the rocks. They suppose that the magnesian rocks of Troy 

 and Richford are connected beneath Jay Peak, in a synclinal basin. 



CHAKACTEK OF THE SERPENTINE OF EOXBUBY AND PROCTORSVILLE. 



Three distinguished chemists of our country have examined the serpentine rocks of 

 Roxbury and Proctorsville, and we present the results of their examinations. 



Dr. A. A. Hayes, of Boston, State Assayer of Massachusetts, communicated to the 

 Boston Society of Natural History, on October 17, 1855, and March 19, 1856, several 

 analyses of these rocks, and remarks upon them, which were republished in the American 

 Journal of Science and Art, Second Series, Vol. XXI, page 382 et. seg. Previously to the 

 analyses he had examined the durability of the Roxbury serpentine, and pronounced 

 it nearly equal to granite for its power to resist decomposition. We quote his analyses of 

 the white veins traversing the Roxbury serpentine, as well as the basis rock itself. 



" I. Analysis [of specimen from Roxbury.] That part which is purely white in color, 

 can be separated from the general mass, in the form of milk-white fragments, translucent, 

 crystalline ; the cleavage planes reflecting a high luster. In hardness exceeds any variety 

 of calcspar ; it scratches the harder dolomites. The powdered mineral loses some humid- 

 ity at 212 F. ; at 450 the whole loss is 0.08 per cent. 100 parts of the dried powder 



consist of 



Carbonic acid, 48.80 



Magnesia, ...... 45.60 



Talc and trace of silicic acid, . . 3.60 



Silicate protoxyd iron, .... 1.96 



99.96 



