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 stalactica) or granular, they are very 
thin, and I have counted more than an hundred in one 
series. By breaking the matrix in whieh 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. 
“hese 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 ‘chafees 
terized Oolite lying beneath, while those of a less defini- 
tive character are regularly piled above it. 
I have endeavoured to represent the appearance of this 
singular stratum in the small sketch which accompanies 
this communication ;* it comprises a section of the rock as 
it presents itself in the road, near the t 
ed, and is Jeena to ‘display: aview 
‘the superin : Jena appear in 
the atk: pave: thelr ation heing pe by the falling 
in of the earth, which likewise covers a part of ne surface of 
the projecting rock. 
I have carefully examined 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 appeare 
f what professor Eaton calls caleiferous slate has any 
connection with this series, it is itself Oolitic; I found a 
formation which answers tolerably well to his description of 
oe rock, situated above the well defined Oolite, but it 
tained a number of the small concretions which distin- 
pas that rock from all others. The strata still higher are 
* See the figure in plate If. 
