382 J. D. Dana—Note on the Bernardston Held-rberg Formation. 
era with the crinoidal limestone; for the former orcs graduates 
into the latter as its calcareous matter and fossils s 
limestone as well as one (No. 5) above. This inferior mica 
slate wants the little disseminated crystals of mica common in 
the other; but it is pimpled with garnets like that. The 
line of outcrops extends for several rods, and runs along within 
a few yards of the limestone, at the nearest aes hardly a yard 
of earth intervening; and the strike and dip throughout cor- 
respond with that of the limestone snide: Basia garnet- 
iferous mica slate below the limestone as well as above, and 
the three strata conformable in dip, there can be no reasonable 
doubt that all are of one formation. The limestone stratum is- 
so placed with reference to those above and below that it could 
not have been originally at the top, and the newest of the series. 
Whatever faulting or inversion be supposed, it must have had 
originally, as it has now, an overlying and an underlying mica 
ey 
The limestone a local depostt in the patna formation.— 
Phe fact that the limestone has not been observed elsewhere in 
isolated calcareous eens in the “Calciferous mica schist,” 
would be regarded as showing the age of the schist; and so it 
hou ere. 
Professor Hitchcock says that if the Cods slate is Helderberg, 
the Calciferous mica schist is unquestionably so too. Admitting 
this to be true, the parallelism between the Bernardston lime- 
stone and the isolated calcareous depcits in the schist becomes 
~ com 
T the hornblende rocks, staurolitic slate, mica schist and asso- 
ciated gneiss are of the Helderber gq formation.—As limestone has 
_ been found in the region only at the one locality in Bernards- 
ton, the evidence of equivalence has to be derived from the 
distribution of its associated rocks. This evidence, east and 
phate of the Bernardston village-plain, is as follows : 
1.) The same garnetiferous mica slate with disseminated 
brown mica erystals set transversely that lengurs associated | 
* My knowledge of the rock formations of Western Vermont is not sufficient to 
warrant an independent opinion with regard to the “ Calciferous mica schist.” 
