ONONDAGA SALT GROUP. 



105 



the Erie canal, the space occupied by its hills enlarging in width towards the west. A few 

 only will be noticed. The one of greatest interest is Reed's and Brewster's on Butternut 

 creek, below Jamesville; this, in the Report of 1839, was mentioned under the name of 

 Hungerford's. A section of this quarry is given in wood-cut No. 20 : 



20. 



The lower part G is a mass of gypsum over twelve feet wide, the bottom not exposed. It 

 18 the largest mass and the best quality of plaster seen east of Cayuga. Its color is not so 

 dark as it usually is in other localities. 



No. 2, of a dark brown color at the bottom, much broken, the parts re-cemented, with 

 cavities or interstices : three feet thick. 



No. 3. Thin fragile layers, with the irregular cavities noticed at the east end of the dis- 

 trict : four feet. 



No. 4. Brown oUve, thin layers, soft or tender : three feet. 



No. 5. Compact layers of a dark drab, which are a water-lime, and are quarried a little 

 beyond the plaster mass, and burnt for that purpose : five feet. 



No. 6, consists of a few thick layers, of hard drab-colored, dull rock, resembling the water- 

 lime of the upper group. It breaks into large irregular blocks. At intervals of a few feet, 

 it shows a vertical series of cavities of sulphate of magnesia, the cavities disposed horizon- 

 tally, strongly contrasting with the rock, being lined with black coloring matter in the state 

 of coal or carbon. The cavities here are larger than elsewhere noticed in the district, some 

 of them being four inches in length. These cavities in other localities appear at the inter- 

 section of layers, where the finer particles of rocks collect, and to which the divisions or 

 layers are owing, and where moisture would always be in greater amount. Here it is dif- 

 ferent, and it is not easy to conceive how they were formed, unless joints existed above, by 

 which water gradually found its way into the mass, attracting the salt which crystallized in 

 the lines of percolation. 



In this mass, and in this quarry, a few casts of the internal part of a small cyathophyllum 

 Geol 3d Dist. 14 



