GEOLOGY. 243 



twelve miles south, tlieiiro iwclvo miles cast, thence twelve 

 miles south, thence six miles west, thence six miles south, 

 thence twelve miles west, thence six miles south, striking the 

 northern boundary-line of the State of Illinois at tlie point 

 wliere tlie line between ranges five and six east of the fourth 

 principal meridian crosses said boundary-line ; thence, with 

 said boundary-line, six miles west, thence twelve miles or 

 thereby south, to the southeast corner of section tliirtcen, 

 township twenty-seven north, range four east of the fiftli 

 principal meridian; thence six miles west, thence three miles 

 south, thence sixteen miles or tlicreby east, to the cast bank 

 of the Missisippi River, about five miles below the mouth of 

 Fever River, and about a mile and a half below the place of 

 beginning, already designated, on the western bank of the 

 Missisippi.* 



'' This lead region is, in general, well watered ; namely, 

 by Pcccatonnica River, Apple River, Fever River, Platte 

 River, Grand River, the head-waters of Blue River, and 

 Sugar Creek ; and on tlie Iowa side by the Little Makoqueta 

 and the lower portion of Turkey River : all of these streams 

 being tributaries of the Missisippi. 



" The higliest points within this region are the summits of 

 the Blue Mounds, two hills of a conical shape, composed of 

 chert and other varieties of Hint rock, in the northeast portion 

 of the tract, and rising to the height of one thousand feet 

 ai)ove the Wisconsin River. The Platte Mounds, also of 

 conical form, and about six hundred feet high, occupy nearly 

 the centre of the lead region. 



" These isolated and towering mounds, so conspicuous a 



• " A few fractional townships, originally included in my special repnrt-s, 

 within the lead region, have been, on re-examination, thrown out, as not 

 strictly belonging to the district w!)ich is likely to aflord jirodurtivo veins 

 of lead ore." 



