12 



NEW YORK STATE MUSEUM 



mile on the west it would indicate here as elsewhere, that it was 

 a deposit of a sand bar running out from the irregular coast line of 

 the time. This deposit in the town of Phelps is the last of the len- 

 tils which the formation assumes in western New York. It is 6 

 feet, 6 inches thick and consists of several distinct layers. In the 

 upper part of the top layer there are many elongate rounded peb- 

 bles and cobbles of black quartzite embedded in the light sandstone 

 and the rest of the deposit is largely of coarse sand with a lumpy or 

 slightly concretionary structure. In these outcrops the only evi- 

 dence of fossils is the presence of a few obscure corals. On Mud 

 creek 50 rods below the railroad bridge at Mertensia, there is an 

 exposure of the same material but more quartzitic, containing 

 the waterlime pebbles, the layer being G to 8 inches thick. 

 In Phelps the sandstone was at one time quarried for fires tone 

 for use in the glass furnaces at Clyde. 



Onondaga limestone 



In general character this important deposit is a compact, dark 

 bluish gray limestone frequently carrying interbedded layers of 

 chert nodules, the limestone itself being bedded in layers from 

 (i inches to 3 feet in thickness. It contains a large amount of 

 carbonaceous matter, which appears on the surface of the layers 

 and in the shale partings between them and discolors most of the 

 strata, frequently giving them a decidedly black appearance. It 

 is removed by gradual decomposition on exposure and the rock 

 slowly assumes a very light bluish gray color. The chert or horn- 

 stone is usually nearly black and slightly translucent, but some- 

 times lighter colored and bluish. It is very unevenly distributed 

 in the beds in some of which it predominates and in others is 

 entirely absent. The nodular layers in which it lies are frequently 

 continuous for long distances and owing to their resistance to de- 

 composing agencies, old exposures of the beds and the innumerable 

 boulders and fragments from them strewn over the region south 

 of the escarpment formed by this formation, have a peculiarly 

 ragged and scraggy appearance. At some of the outcrops one or 

 more of the layers are shaly but only a small proportion of the 

 formation is of this character and all of the remainder, wherever 



