366 



Scientific Geology. 



dition of steatite. Often it is very obvious that the specimen is in an 

 intermediate state between serpentine and steatite. Indeed, all the 

 gradations between the two rocks may sometimes be seen, particu- 

 larly in the beds of serpentine and steatite embraced in gneiss, in 

 Pelham, Shutesbury, and New Salem. The color of the rock in 

 these cases is quite black. (Nos. 886 to 893.) 



3. Serpentine, Talc, and Schiller Spar ? In this variety, also, the 

 serpentine, as well as the foliated mineral which I presume to be 

 schiller spar, are black ; while the talc is green, and sometimes quite 

 brittle. This variety occurs only in Blanford, Russell, and West- 

 field, so far as I have observed. (Nos. 894, 895.) 



4. Serpentine and Carbonate of Lime. The latter mineral in this 

 variety is white, and the former green, or black. The proportions in 

 which they are mixed is very various. The limestone is generally 

 saccharoidal, and thus this rock forms the Ophicalce Grenue of 

 Brongniart, who refers to Newbury as one of its localities. (Nos. 896 

 to 899.) 



Other minerals found in serpentine sometimes essentially modify 

 its characters : such as actynolite, asbestus, massive garnet, compact 

 feldspar, &c. : but such varieties are hardly worth noticing in this 

 connection. 



Topography, Stratification, and Associated Rocks. 



Since I have so particularly described the localities of our serpen- 

 tine in the first part of my Report, it may be practicable, without 

 confusion, to bring together all that I know of its stratification and 

 associations, in a topographical order. 



It will be seen, by the map, that the most numerous and important 

 beds of this rock occur near the central parts of the Hoosac moun- 

 tain range, and especially in connection with, or in the vicinity of, 

 the talcose slate. In Windsor are two beds. The most easterly bed 

 is only a few rods from a bed of steatite ; the latter appears in the hill 

 forming the south bank of a branch of Westfield river, and the for- 

 mer in the opposite bank. Both the beds are obviously interstratified 

 with chlorite slate, not far from the junction of this rock with com- 

 mon talcose slate. Its color is a pleasant rather deep green ; its 

 structure between granular and splintery ; and it contains small dis- 

 seminated fragments of chromate of iron. It is distinctly stratified ; 

 the strata running north and south, and standing nearly perpendicu 

 lar ; which is the usual dip of the rocks in the vicinity ; though the 



