GENERAL GEOLOGY OF THE DISTEICT. 451 



nature of the fragments of the conglomerate and the subsequent tilting- df 

 the rocks were disregarded. We have here, however, nothing but what is 

 known to occur at any sea clift' in which its detritus becomes a part of an 

 luiconformable newer series of rocks In the immediate vicinity of this 

 clitf, a short distance to the northwest, is a ravine in which the contact 

 between the crystalline and fragmental series is again found. The frag- 

 mental rock is at this place a recomposed granite which so closely resem- 

 bles the rock from which it is derived that it is impossible in the field to 

 locate the exact junction line. In thin section the fundamental difference 

 between the two rocks is apparent at a glance. Here practicalh' all the 

 material of the fragmental rock was derived from the granite immediately 

 underlying it. 



A little farther to the northeast (near the center of the north half of the 

 NW. \, Sec. 28) a chert-conglomerate is found in several places but a few 

 paces from the granite. These chert-conglomerates are in all essential 

 respects like that found near the Palms mine, already described. While it 

 includes a large ({uantity of granite debris, including (quartz, feldspar, 

 biotite, and complex areas composed of these minerals, it has a cherty 

 backgr()un<l which contains abundant angular chert fragments. It appears 

 that here, as near the Palms, the Quartz-slate member has derived material 

 from both the Southern Complex and the Chertv limestone. 



From the foregoing it appears that there are definite proofs of a strati- 

 graphic break between the Southern Complex and the Penokee series at 

 ten places. Two of the localities (see PI. ii), both being actual contacts 

 accompanied by basal conglomerates, are above the Western schist, tlie 

 lowest layer of the upper series here being the Quartz-slate. Two of the 

 localities, both again being contacts, one accompanied by a basal conglom- 

 erate, ai"e above the (Jentral granite, the lower rocks of the upper series 

 here being again the Quartz-slate. One of the places is above the Eastern 

 schist, the contact being- found, but no basal conglomerate appearing. The 

 lowest layer of the xipper series is liere the quartzite, which occasionally 

 appears at the base of the Quartz-slate. Finally, five of the localities are 

 above the Eastern granite, l>asal conglomerates or recomposed granites 

 occurring at each locality, while at two of the places ai'e actual contacts. 



