416 
GEOLOGY OF THE FIRST DISTRICT. 
they are mostly hemispherical, but many of them are globular, and vary in size from half an 
inch to two feet in diameter ; they are obviously composed of a series of successive layers, 
nearly parallel and perfectly concentric. These layers have a compact texture, are of a dark 
blue or nearly black color, and are united by intervening layers of a lighter colored calcare¬ 
ous substance, either stalactitical or granular they are very thin, and I have counted more 
than a hundred in one series. By breaking the matrix in which they are imbedded, 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 exactly the ^me. 
“ These interesting concretions appear to be confined solely to one stratum of the series, 
and this stratum evidently accompanies the oolite in its whole extent, and is undoubtedly a 
variety of the same series, the best characterized oolite lying beneath, while those of a less 
definite character are regularly piled above.”! 
The structure above described is illustrated on PL 40, fig. 2.% 
The same kind of rock was seen in Galway, both north and south of the road that leads 
east and west through Galway corners. Between Galway corners and Diamond hill is a 
small anticlinal axis ranging eastward and westward, the strata dipping to the north and 
south. The next northward locality seen in Galway, is about three miles north of the village 
called the Corners, and near the primary rocks. 
“ There is a bed of oolite about four miles north of Saratoga springs. It is of a dark 
color, and is made up of grains about as large as a pin’s head. On analysis, I found its com¬ 
position to be as follows in 100 grains : , 
Carbonate of lime __95.00 
Silica and alumina, with some carbonaceous matter. _ . _ 5.00.” ^ 
Oolitic rocks have also been observed in the blue and grey limestone of the Calciferous- 
group ill various parts of Orange county,|| viz. on Big island, in the great marsh called the 
Drowned lands ; near Edenville, in Warwickseveral places near the village of Warwick ; 
half a mile north of New-Milford, and on Pochunk neck. Dr. Horton, in his description of 
the limestones of the Champlain division in Orange county, says, 
“ On Pochunk neck, about three miles from the New-Jersey line, some of the layers 
differ from any seen in the county. In some of the perpendicular cliffs, the edges of many 
layers are exposed, one above another. Some of these are of the usual character, others 
are oolitic, but the round granules are bluish white quartz ; other layers still are slaty, 
♦ Some of the round masses described as concretions analogous to oolite, are organic, and will be described in the Palaeontolo¬ 
gical Report. Similar concretions and ovoidal masses in a similar geological portion, and associated with equivalent rocks, have 
been observed in various parts of the valley of the Mississippi, particularly in Missouri and Wisconsin. 
+ American Journal of Science (Steel), Vol. 9, pp. 16,18. 
t Copied from the American Journal of Science, Vol. 9, Plate 2. 
§ Prof. Beck’s Repoit, 1840, p. 96. 
11 The extension of the same limestone contains oolite in Franklin in New-Jersey, and near Easton in Pennsylvania (American 
Journal of Science, Vol. 18, p. 376; Vol. 19, p. 398). 
