EELATIONS OF THE A.IIBIK QUARTZITE. 299 



character of the usual transition may be well seen at the conglomerates 

 occurring' south of the Piatt mine, east of Cascade Brook, and south of the 

 Goodi'ich and .Saginaw mines, in sec. 19, T. 47 N., R. 27 W (See Section VI.) 

 Along the southern belt the Ajibik quartzite for much of the distance is 

 narrow, consisting of a basal conglomerate alone, or of a basal conglomerate 

 with a comparatively thin belt of quartzite. However, the belt is of vari- 

 able thickness, this doubtless being due to irregularities of the Basement 

 Complex at the time of the transgression of the sea. While this belt of fer- 

 ruginous conglomerate or quartzite is placed with the Ajibik, it is probable 

 that much of it really belongs in time to the Siamo slate or to the Negaunee 

 formation, and that this part of the area was above the water during Ajibik 

 time. This is shown to be highly probable by the occurrences in sec. 30, 

 T. 47 N., R. 26 W. (Atlas Sheet XXXII). Here, upon opposite sides of a 

 narrow syncline, directly below the Negaunee formation as mapped, are 

 the Ajibik quartzite and Siamo slate, the former close to the Palmer gneiss. 

 Near a shore was deposited a sandstone, while farther from the shore mud 

 or sandy mud was being deposited. However, as this southern belt is litho- 

 logically like the Ajibik quartzite, and the part which belongs in time with 

 the Siamo slate can not be determined, it is all platted as Ajibik. 



THICKNESS. 



As in the ease of the })revious formations, it is exceedinglv diflficult to 

 give any accurate estimate of the thickness of the Ajibik quartzite. As 

 the folding is very complex west of Goose Lake, where the most continuous 

 exposures are, any computation based upon the breadth of outcrop and 

 average dip would be sure to give conclusions far from the truth. In the 

 belt extending north and east from this area there are no continuous expos- 

 ures with well-determined dips for the entire breadth of the formation. 

 South of Carp River, in .sees 6 and 7, T 47 N., R 25 W (Atlas Sheet 

 XXXVII), there is, perhaps, the best opportunity to make an approximate 

 estimate. Here the breadth of the formatioii appears to be about 1,200 or 

 1,300 feet. This, with a dip of 35'', would give a thickness of about 700 

 to 750 feet. East of Teal Lake (Atlas Sheet XXX) it is perhaps possi- 

 ble to give the maximum thickness of the slate and (piartzite from the base 



