794 NEW YOEK STATE MUSEUM 



organic matter. Whetlier or not clay underlies tlie marl is not 

 tnown. 



Marl also. occurs on tlie land of J. C. Austin, 2 niiles north of 

 Oanastota, and about a fo-ot of it is exposed in the ditch in J. D. 

 Oonley's land, 1 mile north of town (pi. 43, 44). So far as 

 tnown none of this marl has thus far been utilized. The follow- 

 ing is an analysis of the material. 



Silica 2.1 



Akmiina ) ^ ^.^ 



Ferric oxid 



• o 



Lime carbonate 87.1 



Magnesium carbonate 2.31 



Insoluble and organic matter . 11 



Another deposit of marl is found south of Chittenango Falls. 



Monroe county^ 



The l^iagara is the most prominent and extensive limestone in 

 the county, though Clinton, and Onondaga are also known. 

 Quaternary marl is likewise found. 



The [N^iagara limestone extends across the county as a belt 

 several miles wide, its northern edge passing through the towns 

 of Penfield, Brighton, Ogden, Gates and Sweden. The upper 

 magnesian member generally forms the outcrops, and the weath- 

 ered surface of the rock has a peculiar granular and spongy ap- 

 pearance. The upper member, or Guelph limestone, is a grayish 

 brown, finely crystalline limestone containing numerous small 

 cavities. The rock is very low in silica and has a large amount 

 of magnesia, making it well adapted for refractory linings in 

 furnaces. The lower beds of Niagara limestone are hard, com- 

 pact and generally highly silicious in Monroe county. The !N"i- 

 agara shale underlies the Niagara limestone, and the transitional 

 beds between the two sometimes furnish a natural cement rock. 

 Beds of this nature outcrop at Shelby falls in the town of Barre. 



1 Hall, James. Geol. 4tli dist. N. Y. p. 422. 



