STRATIGRAPHY OF MOHAWK VALLEY AND SARATOGA CO. 481 



Feet 



B^ Drab colored stratum similar in lithologic ap- 

 pearance to the Birdseye. f =28 i 



B* Massive dark gray limestone forming the 

 floor of the quarry. This stratum contains numer- 

 ous specimens of Columnaria alveolata 

 Goldf. and Buthotrephis succulens Hall 

 which are specially well shown. 1=29^ 



B^ Dark blue rather thin bedded limestone thicken- 

 ing toward the western end of the quarry. It is not, 

 however, used for " marble" but burned for quick- 

 lime as is some of the rock from the next zone. 3 |=36i 



B^ Massive, fine grained, dark gray, compact lime- 

 stone, the " black marble " of the quarrymen. This 

 zone which is in the Trenton limestone divides into 

 three beds; the lower massive one 4 feet, 3 inches in 

 thickness, the middle massive one 5 feet, 6 inches and 

 the upper one composed of three thin layers 3 feet 2 

 inches. I2f=^5-| 



B"^ Thin shaly limestones extending to the top of 

 the quarry. I2j=58i 



The dark gray compact limestone of zone B^ when sawed is 

 capable of taking quite a polish and this has suggested the name of 

 marble. The characters of the Black river and Birdseye subforma- 

 tions appear to be so blended in this quarry that it becomes diffi- 

 cult to separate them. The following section was measured on the 

 south bank of the Hudson river immediately below the street bridge 

 between Glens Falls and South Glens Falls: 



54A1 Drab cofored Hmestone with vertical mark- 

 ings like Phytopsis tubulosa Hall. 1 1 in- 

 ches measured at the water's edge and possibly i 

 foot in thickness. The rock is very compact and fine 

 grained but darker in color than the Birdseye lime- 

 stone in the Mohawk valley though it weathers to a 

 similar light gray color. The equivalent of zone B^ 

 on the north bank. 



A^ Dark gray to bluish, lumpy limestone contain- 

 ing Columnaria alveolata Goldf., Strep- 

 t e 1 a s m a and some other fossils as well as black 



Feet 



