Blanford Limestone. 305 



caverns that have been described in the second part of this report. 

 Some of the springs in Williamstown deposite calcareous tufa. 



According- to Cleaveland's Mineralogy, yellow tourmaline has 

 been found in Dalton, near the Housatonic, in granular limestone. 



Blanford Limestone. 



After the publication of the first edition of the first part of my Re- 

 port, Mr. Simeon ShurtlefF of Blanford discovered a bed of serpen- 

 tine in the northwest part of that town, and in the vicinity, a bed of 

 limestone. The former rock will be described in another connection. 

 The latter will be noticed here. Since their discovery, I have had 

 opportunity to examine them personally: but for the specimens in 

 the collection, I am indebted to Mr. Shurtleff 



The bed of serpentine is about four miles northwest of Blanford 

 meeting house, on the northeast side of a pond. Immediately on the 

 west it is succeeded by hornblende slate, which is only a few rods 

 wide, and then succeeds granitic gneiss. The limestone is about one 

 mile south of the serpentine, and about the same distance as the ser- 

 pentine, east of the granitic gneiss : and although no hornblende slate 

 appears between them, at the surface, probably it exists there. In- 

 deed, no rock except diluvium is seen in place around the limestone. 

 It shows itself at the surface only over a space whose diameter is 

 about a rod. Its stratification is indistinct ; though there is an ap- 

 pearance of parallel division, corresponding to a plane which runs east 

 and west, and dips south about 45. 



This limestone is coarsely granular, white, and crystalline ; though 

 it is mixed with a foreign mineral, perhaps augite, in considerable 

 quantity; and this may prevent its being profitably reduced to quick- 

 lime. It is well worth the trial, however, in a region where no lime 

 stone is found. (Nos. 477, 478.) 



No. 476 was broken from a coarsely granular limestone bowlder 

 near the meeting house in Blanford. It contains numerous plates 

 of graphite disseminated through the mass, and much resembles 

 specimens that I have seen from the shores of lake Champlain : Nor 

 should I think it strange, if it should appear that this bowlder was 

 brought from thence by the diluvial current, which, as I have shown 

 in -another place, once swept over the western part of the State from 

 the northwest. 



Micaceous Limestone. 



This rock might very properly be regarded as a variety of mica 

 slate : for usually it contains both mica and quartz, the latter always ; 

 39 



