LIST OF SPECIMENS IN THE ECONOMIC COLLECTION. 57 



Niagara Group. 



1. A block of one cubic foot: one face showing rock fracture, one po- 



lished face showing the regular crinoidal columns, the other faces 

 dressed in seveial ways. From Lockport. 



2. A block of one cubic foot : one face showing rock fracture ; one face 



polished, a fine grey marble ; the other faces variously dressed. 

 Lockport. 



3. One block of a cubic foot ; one face showing rock fracture ; the other 



faces variously dressed to show adaptation of the material. A fine 

 gray block. Lockport. 



4. A block sixteen inches to seventeen inches thick ; all the sides dressed. 



A gray stone. Lockpon't, N. Y. 



Lower Helderberg Group. 



A block of triangular form, with faces polished, showing variegated 

 colors from crinoidea and other fossils. 



[Tentaculite limestone tit base of Lower Helderberg group.] 



A block of polished black marble two feet four inclies long, thirteen 

 inches wide and seven inches thick, resting on a large block of the 

 same stone, one face showing rock fracture and the other faces 

 dressed as a building stone ; showing the adaptation of this rock 

 for building and ornamental uses. 



Upper Helderberg or Onondaga Limestone. 



1. A block of one cubic foot; light gray color : one face rock fracture, 



one face polished, the others variously dressed. From near Syracuse. 



2. A block (f a cubic foot ; bluish gray color : one fage showing rock frac- 



ture, the others variously dressed. Near Syracuse. 



3. A block ten by seven and nine inches ; gray stone, with dressed and 



fractured faces. 



4. On(3 block ten by seven and nine inches ; gray stone, dressed faces. 



5. One block of a foot by eight and ten inches; dressed faces, with one 



showing rock fracture. (The particular quarries of 3, 4 and 5 are 

 not known.) 



6. A slab twelve by eighteen inches ; light gray stone, polished face, show- 



ing oiganic remains. 



7. A slab twelve by eighteen inches; color gray or bluish gray, and with 



one face polished. 



[Assem. No. 239.] 



