GEOLOGICAL REPORT. 37 



ties of Galena have been raised from these mines since they 



were opened, not less than pounds. They often discover 



masses of this ore so large that it is found somewhat difficult to 

 raise them to the surface. 



The statistics of one shaft will give an idea of the quantity 

 of ore raised and the profits of mining at this place. Mr. Fra- 

 zier's shaft, as I am informed, yields 100,000 pounds of galena 

 per month. In one week alone, it yielded 50,000, which at 

 |20 per thousand, would amount to $1,000 ; deduct $150 for 

 expenses, and the profits of this shaft alone were $850 for that 

 week ; they average about $1400 per month. 



The miners, collected here from all parts of the world, seem- 

 ed to be agreed that the Granby Mines are the best they have 

 ever seen. This opinion of the miners, the vast quantity of lead 

 raised in so short a time and in a locality so far from the means 

 of cheap transportation, and the geological features of the coun- 

 try, all unite in proving these mines the most valuable in the 

 world. 



The accompanying sketch, Plate XVII., represents a portion 

 of Granby as it appeared in June, 1857. 



The Center Creek Mines, in Jasper county, are situated on 

 the boder of the prairie extending from Carthage westward to 

 the territory, on a branch leading into Center creek, in Sec. 

 36, T. 29, R. 33, and Sec. 31, T. 29, R. 32. The following- 

 section will give a correct view of the geological features of the 

 locality : 



No. 1 10 to 20 feet of chert, limestone and clay, broken and mingled promiscu. 

 ously, and more or less cemented into a solid mass. The limestone is 

 not so abundant as the clay, and the chert predominates over both. 



No. 2 5 feet of regularly stratified bluish crystalline limestone. 



No. 3 10 feet same as No. 1, save the limestone is more abundant. 



No. 4 (?) of limestone, same as No. 2. 



On the east side of the run, the conglomerate of No. 1 is 

 overlaid by eight or ten feet of brown stratified sandstone, which 

 is the same as that at the first locality named. Irregular veins 

 of galena, very variable in thickness, cut through this conglom- 

 erate of chert, etc., and through the limestone, in directions 

 approaching an east and west line, and varying from a perpen- 

 dicular to a horizontal. The galena usually fills the fissure, 

 when it is small, without any vein rock or gang ; but when the 



