186 THE PENOKEE IKOiST BEARING SERIES. 



and make it a question whether the entire Iron-bearing- series is liere cut 

 out. This statement is at variance with the maps of tlie Geoh^o-y of Wis- 

 consin, whicli indicate a continuity across R. 4 W., Wisconsin, not only of 

 tlie Iron-bearing meml)er, hut of tlie underlying and overlying members of 

 the Penokee series.' It was known at the time these maps were made that 

 tlie Penokee range, with all its characteristic rock exposures, ends abruptly 

 in the eastern part of T. 45 N., R. 4 W., Wisconsin, being succeeded to the 

 westward by a low, marshy country, with l)ut rare exposures, the Penokee 

 range rocks not reappearing until in the vicinity of the bold ridge in the 

 NE. ^ of Sec. 1>4, T. 44 N., R. 5 W., Wisconsin. The late Mr. C. E. 

 Wright, however, traced through the intervening low country a line of 

 rather feeble magnetic attractions which he considered to establish the con- 

 tinuity of the Penokee range rocks beneath the drift covering. Accepting 

 Mr. Wright's conclusicm, the surface maps Avere drawn accordingly. 'As to the 

 magnetic attractions, it is to be said that they were too feeble to base any 

 certain conclusion upon, being perhaps explicable by the considerable 

 cpiantity of magnetite occurring in the gabbro, which appears hei*e to usurp 

 the place of the Penokee rocks. Still, it is not im|)ossil)le that this line of 

 attractions may be due to the Penokee iron belt itself, buried here under- 

 neath a considerable drift covering. In the north half of Sec. 28, T: 44 

 N., R. 5 W., Wisconsin, as alread}- stated, outcrops of the Penokee series 

 reappear, and from here for a distance westward of 4 miles exposures of 

 the Iron-bearing and Quartz-slate members are sufficienth- fre([iient to indi- 

 cate their continuity through this distance. The last exposure on this line 

 is met with in the S. h of Sec. 20, T. 44 N., R. o W., Wisconsin, l>eyond 

 which point no exposures have yet been found luitil those met with in the 

 SE. \ of Sec. 2(), T. 44 N., R. 6 W., Wisconsin, where the characteristic 

 rocks of the iron belt are seen again. Still farther west Mr. Wright traced 

 a line of feeble magnetic attractions as far as the north side of lake Xiuua- 

 kagon. In the uftrthern ]»art of T. 43 N., K. (! W., Wisconsin, l)c\dnd lake 

 Numakagon, no further exposures of the Penokee series have been met with, 

 while in Sec. 20, T. 43 N., R. 7 W., Wisconsin, the occurrence in close 



' See Atlas o( the Oeiil. of Wis., Pis. xxii aud xx^■II. See particularly the latter plate for the 

 poaitiou of all exposures kuowu at that time. 



