17() Till'; I'KNOKKK IKON-BEAKING SERIES. 



the section at alxmt 100 steps soutli of tlic iiortlieast corner. lunnediately 

 to tlie nortli ot' tins (piartzite, l)nt not diri'ctly in contact with it, are ex})os- 

 mcs of the Iron-hearinj^- nieniher, and imnieiUately to tlie south hirg'er ones 

 of .;! hiotitic and cldoritic shite of the Quartz-shite. Still l;ir<^er exposures of 

 (juartzite ami hiotitic (piartz-slate aris shown alon«i' the crest of tlu^ I'eiiokee 

 ra-n<'e in its course across Sec. 17, T. II N., U. 8 \V., Wisconsin. The east- 

 ernniost one of thi-se (exposures shows a contact on the north with a nia;^- 

 uetitic schist. This contact lies f)M steps south and 400 steps west of the 

 northeast corner of the section. Similar lar<;'e exposures show in the 

 northern part of Sees. If) and Ki, hut nuich more striking- and complete 

 exposures arc those met with in the vicinity of Penokee gap, where Bad 

 river passt's the I'enokee range from south to north. The position and 

 extent of these exposures will be best understood by an inspection of 1*1. 

 xxxvi. The most striking of them is that whicdi forms a bold hill at the 

 southern end of I'enokee gap itself Here the entire width of the Quartz- 

 slate is se(U\, from its contact with the cliert of the underlying limestone 

 formation on the south, northward to its contact with the iron formation. 

 The latter contact is l)etwe(m the usual uppermost vitreous qnartzite of the 

 Quartz-slati' and an actinolite-magnetite-slate of the Iron-l)earing member. 

 Contacts are also .seen at two ])oints res])ectively 3,00 and 100 i)aces farther 

 west. Except in the; uppermost horizons where we have the usual vitreous 

 and relatively massive (juartzite, the greater portion of the rock here exposed 

 is (piite thinly slaty, seams of light and dark gray and light and dark 

 greenish slate alternating rajiidly with one another. On the whole these 

 slates are more generalh- of the cldoritic and biotitic phases above described. 

 Proceeding farther eastward the next very noteworthy exposures are those 

 at mount Whittlesey on the south side of tlu^ Penokee range. This bold 

 south-facing dill' lies at the corner of Sees. 8, II, IC, and 17, T. 44 N., R. 2 

 W., Wisconsin. The northward angle of inclination of the slate here varies 

 from 5()'^ to (jf)"^, the edges of the inclined layers projecting on the face of 

 the clilV in such a nianner as to make an exceedingly jagged and irregular 

 precipice. The greater part of the slate here belongs to the cldoritic and 

 biotitic (juartz-slate phase. Quite a large portion of the thickness of the 

 formation is exposed at the gorges of C^arrie's creek, NE. :| Sec. 11, T. 44 N., 



