GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 



73 



represented by a somewhat banded bluish rock without visible 

 fossils which was found on the very edge of the limestone about 

 four miles to the northeast at Swartoutville, a hamlet two and one- 

 half miles north of Brinckerhoff. On the Haight farm the fossil- 

 iferous limestone is well exposed in the fields, but in the brush it is 

 followed with great difficulty. This rock, or that with which it is 

 interbedded, is overlain by a calcareous conglomerate in certain 

 places. 



The fossiliferous limestone is very dense and compact. It is 

 quite impossible to remove the coils from the smooth surface. A 

 hard blow with the sledge simply chips the rock into small pieces 

 with conchoidal fracture. The chisel makes no impression. 



The coils are most distinct when at right angles, or nearly so, to 

 the axis of the whorls. They then show as fine spiral lines, 

 resembling a fine loosely-coiled watch spring, which have weathered 

 out very sharply into bas-reliefs. When in the plane of the axis, or 

 at a small angle with it, the lines are thick and patchy. The fine 

 coils vary in diameter from one and one-half inches to three-fourths 



Fig. 22 Whorls of a discoidal gastropod identified as Ophiletacompacta Salter, from the 



ledge shown in plate 12 



of an inch. The medium-sized are most abundant. They bear the 

 closest resemblance to the discoidal gastropod O p h i 1 e t a 

 c o m p a c t a Salter, as described for the Calciferous of the 

 Quebec groups (see plate 12). 



1 Canadian Organic Remains, 1859. Decade i, p. 16, plate 3. 



