November 21, 1870. 



The President in the chair. 



Four members present. 



Publications received were laid upon the table by the Corres- 

 ponding Secretary. 



Lieut. Clifford exhibited several specimens of minerals (topaz, 

 sulphuret of nickel, and fluor in cubic crystals), some fossils from 

 the Lami-street sewer excavations at St. Louis, and moss agates 

 from the vicinity of Fort Laramie, and a silicious cast of a shell. 



Dr. Engelmann exhibited the large pods of Canavalia raised by 

 him from seeds from Sonora, originally from the East Indies, not 

 maturing in this climate, edible, and of a bean-like taste. 



Mr. G. C. Broadhead communicated the following paper on the 

 Mineralogy of Cole County, Missouri : 



GENERAL GEOLOGY. 



In the northern portion of the county is a limestone area of Carboni- 

 ferous and Devonian rocks. But the greater part of the county includes 

 formations in which most of the rich mineral deposits of Missouri are , 

 found. I mean the Magnesian Limestone series of the Missouri Geologi- 

 cal Reports. 



In Cole County we have the 2nd magnesian limestone, 2d sandstone, 

 and 3d magnesian limestone. The base of the 2d magnesian Iime^tone, as 

 observed, occupies the tops of hills and the bluffs from Jefferson City to 

 the south-west corner of Cole County, appearing low down, near the river, 

 at Jefferson City, and rising rapidly to the tops of the hills within two miles. 

 The 2d sandstone crops out along the Moreau and Osage, and the 3d mag- 

 nesian limestone forms the main bluffs of the latter stream. 



LEAD MINES. 



The lead mines of Cole County occur in the lower beds of the 2d 

 magnesian limestone, and include various deposits on South Moreau, 

 Fowler's mines and Clark and Eaton's mines. 



Clark a7id Eaton's Mines. — 1 hese mines lie due south of Hickory Hill, 

 on the waters of Little Tavern Creek. The country around is hilly, the 

 hills rising above the valleys from 200 to 300 feet, by long slopes, over 

 which are scattered stunted oaks and prairie grass. Half-way down the 

 hillbides the rough cellular beds of 2d magnesian limestone crop out; in 

 this rock occur a few univalve shells. 



The ore at these mines is pure galena (sulphuret of lead) associated 

 with a gangue of heavy spar (sulphate of Baryta), calc spar, and magne- 

 sian limestone. Associated with the lead and gangue rocks are beautiful 

 crystallized forms of iron ore, of the brown hematite variety, not occur- 

 ing in sufficient quantity for economical purposes, but forming beautiful 

 cabinet specimens. 



