1880.] 



197 



logical Survey of the Territories ; and the Ministerio de 

 Fomento, Mexico. 



Two pieces of slag from the site of the earliest iron fur- 

 nace in Virginia was presented to the cabinet by Mr. Phillips, 

 for Mr. R. Alonzo Brock. 



Prof. Cope was, on motion, permitted to withdraw for 

 immediate publication elsewhere his communication on 

 the Vertebrata of the Wind River Eocene beds, the princi- 

 pal features of which he described, and exhibited the lower 

 jaw of Bachyopsis hiscidens in illustration of the extraordi- 

 nary character of these fossils. Of 46 species studied, 26 

 species (and 3 genera) are new. The collection is specially 

 important as placing the AVind River beds (hypothetically) 

 between the Bridger beds above and the Wasatch beds be- 

 low, types peculiar to each being found mingled in it. 



Mr. Lesley read extracts from a letter from Mr. Andrew 

 S. McCreath, Chemist in charge of the State G-eological 

 Labratory at Harrisburg, giving an analysis of a 2J?<re dolo- 

 mite exposure, in mass, in Franklin county. 



Harrisburg, Dec. 10, 1880. 

 "While selecting samples of the iron ores in the Mt. Alto district, CoL 

 Wiestling showed me a limestone quarry or opening which, on one of your 

 visits, you thought was partly unaltered blue carbonate of iron, with possi- 

 bly 18 to 20 per cent, metallic iron. Samples were carefully selected — 201 

 pieces for sample — and analysed with the following results : 



Carbonate of lime 51.743 



Carbonate of magnesia 43.486 



Carbonate of iron 665 — 0.321 % iron. 



Alumina 222 



Sulphate of lime 046 



Phosphate of lime 065 



Silica 4.090 



100.267 

 " Calculating the carbonates of lime and magnesia to 100 parts wc get 

 the following as compared with a true iithological dolomite : 



Shiery Quarry, Mt. Alto. Dolomite. 



Carbonate of lime 54.36 54.85 



Carbonate of magnesia 45.64 45.65 



100.00 100.00 



" I find this extremely interesting, for it is the only true dolomite I have 

 yet tound in such large quanlitj' in this State." 



