480 NEW YORK STATE MUSEUM 



Feet 



A^ About 15 feet of light gray calcareous sand- 

 stone shown in the wall of the quarry which separates 

 into three beds ; the lower one 7 feet^ 6 inches in thick- 

 ness, the middle one 4 feet and the top one 3 feet. 

 There are masses of calcite and flint in the rock,, also 

 quartz crystals. The wall of this quarry is well shown 

 in the accompanying picture. I5=55 



A^ Calciferous ledges partly covered to the edge of 

 the woods. 30=85 



Gleni Falls lectioiiB 



Along the banks of the Hudson river at Glens Falls are ex- 

 cellent exposures of the Trenton limestone, which has been ex- 

 tensively quarried. The Finch and Pruyn quarry on the northern 

 bank of the river affords an excellent opportunity to study the 

 different zones of this limestone as may be seen in the following 

 section: 



Feet 



54B1 A calcareous sandstone 2 feet of which was 

 above the river level at the locality measured. This 

 has usually been referred to the Calciferous formation^ 

 but Mr Walcott has stated that in the vicinity of 

 Glens Falls he is " inclined to think that it is impos- 

 sible to recognize, by lithologic characters, the Cal- 

 ciferous formation as distinct from the Chazy lime- 

 stone horizon; and at Glens Falls M a c 1 u r e a 

 magna [a Chazy species] and great numbers of 

 an O p h i 1 e t a like O. compacta [a Calciferous 

 species] are found in the same stratum of rock but a 

 little distance beneath the Trenton limestone, an oc- 

 currence that renders it very difficult to state what is 

 to be assigned to the Calciferous horizon in this 

 region."^ 2= 2 



B^ At the base of this zone is a shaly parting, then 

 a limestone in which is a large specimen of C o 1 u m - 

 naria alveolata Goldf. and above is thin to 

 thick bedded dark blue lumpy limestone, the thicker 

 layers of which contain fossils. The C o 1 u m - 

 naria in this zone is apparently at the same horizon 

 as that noted in Barton's section (p. 428). 25 | =27 1- 



ilSth annual report N. Y. state geologist, p. 424. Bee base of section on p. 428. 

 »U. S. geological survey, bul. 30, 1886, p. 22. 



