7 1 SPARRY LIMESTONE. 



tiona of the rame mass. Other causes also Beem to have operated al times, in such a manner 

 a* to break up the already consolidated strata, which were Bubsequentlj reconsolidated 

 without removal; at least we find angular fragments united by the intervention of calca- 

 reous spar. 



No fossils bave yet been discovered in iliis rock, though it musl be confessed that sulli- 

 cient examination lias nm been made for microscopic bivalves. In searching for fossils, it 

 will be necessar] to caution against the mistake which might be made in some localities, 

 1>\ confounding the Calciferous sandstone with the Sparry limestone. 



MINERAL CONTEXTS. 



Sulphurets of lead and zinc. The Sparrj Limestone is the depository occasionall) of thin 

 \ eins of the sulphurets of lead and zinc. Two localities ha\ e been know a for many years, 

 namely. Alteram in Dutchess, and Whilecroik m Washington counties. The former is 

 the most important, but has not been profitably worked; the latter is a verj insignificant 

 mine, furnishing only small bunches of ore connected together bj very thin strings of the 



same. 



RANGE INn EXTENT. 



Tin- rock passes not tar west of the dividing hue between Massachusetts, Vermont and 

 New-York. By townships, we find n passing through Ancram, Hillsdale, Canaan, New- 

 !.• 'anon, Berlin, Petersburgh, Hoosic, Whitecreek, the wesl pari of Arlington (Vermont), 



and onwards in the same range north through the eastern townships of Canada East. 

 Ann passing through the tunnel of the Western Railroad, where it is al Least two hundred 

 and fifty feet thick, we pass a succession of uplifts which bring up this rock in low hills: 

 these continue about four miles. It is evident thai bere we pass over the same mass 

 end times. But as I have already observed, it may not he found at all al many points 

 in the direction of the strike ; while at other points it seems to expand widely, as between 

 Canaan and West-Stockbridge. It extends two miles wesl of the New-York State line, 

 upon the Western Railroad, where a is succeeded hy the Taconic slate. 



