18 Oolitic Formation of Saratoga County, N. Y. 



pact texture, are of a dark blue or nearly black colour, and 

 are united by intervening layers of a lighter coloured calca- 

 reous substance, either stalactical or granular, they are very 

 thin, and I have counted more than an hundred in one 

 series. By breaking the matrix in which they are imbed- 

 ded, they drop out entire, and may be readily reduced to 

 any smaller size, by merely throwing them upon the rock — 

 the concentric layers easily separate, leaving the form ex- 

 actly the same. 



These interesting concretions appear to be confined 

 solely to one stratum of the series, and this stratum evi- 

 dently accompanies the Oolite in its whole extent, and is 

 undoubtedly a variety of the same series, the best charac- 

 terized Oolite lying beneath, while those of a less defini- 

 tive character are regularly piled above it. 



1 have endeavoured to represent the appearance of this 

 singular stratum in the small sketch which accompianies 

 this communication;* it comprises a section of the rock as 

 it presents itself in the road, near the bank above mention- 

 ed, and is intended to display a view of its edge and surface, 

 toget'jer with the superincumbent strata, as they appear in 

 the bank above, their union being obscured by the falling 

 in of the earth, which likewise covers a part of the surface of 

 the projecting rock. 



I have carefully examiiied the different formations in the 

 vicinity of this series, and, although the connection is ex- 

 tremely broken and rendered rather ambiguous by the in- 

 tervention of diluvial deposits, I have come to the conclu- 

 sion that the Oolitic formation, rests on the metalliferous 

 or mountain-lime rock, and that this last overlies the cal- 

 careous sand-rock, both these formations occurring in such 

 situations as to induce the belief of their being thus con- 

 nected, although I could find no place where their actual 

 union appeared. 



If what professor Eaton calls calciferous slate has any 

 connection with this series, it is itself Oolitic ; I found a 

 formation which answers tolerably well to his description of 

 that rock, situated above the well defined Oolite, but it 

 contained a number of the small concretions which distin- 

 guish that rock from all others. The strata still higher are 



* See the figure ia plate II, 



