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 althou gh 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 ; 

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