ON THE LAKE SUPERIOR REGION 99 



stone, and two interpretations are possible as to its position: it 

 may be regarded as the lower slate conglomerate under the lime- 

 stone, or it may be regarded as an equivalent to the conglomerate 

 south of the limestone, being repeated by an anticline or possibly a 

 fault. The limestone has a steep dip to the north, and, accepting 

 either alternative, it must be regarded as overturned. 



We next visited the abandoned limestone quarry north of Garden 

 River station. Here we found the conglomerate, marked by Logan as 

 the upper slate conglomerate, within a few paces of the limestone. 

 This conglomerate is in all respects similar to the average of the con- 

 glomerates before mentioned, except that it contains very numerous 

 limestone fragments. The party has no doubt that the limestone for- 

 mation was laid down, and that a considerable erosion interval 

 occurred before the deposition of the conglomerate upon the limestone. 

 The slate-conglomerate belt north of the limestone was examined, 

 and while it was not found in contact with the limestone, it was seen 

 to increase in coarseness as the limestone is approached, and across 

 the little ravine which separates the conglomerate from the limestone 

 it was found to contain numerous limestone fragments. We there- 

 fore conclude that the rock on each side of the limestone is the upper 

 slate conglomerate, the structure probably being anticlinal, possibly 

 with faulting. This conclusion suggests that the same relation 

 obtains at the Root River locality above described. 



On the limestone point on the east side of Echo Lake we found 

 the following ascending succession, with monoclinal dip to the south- 

 east: (1) white or gray quartzite, grading through graywacke into 

 (2) a thin belt of conglomerate not exceeding twenty feet in thickness 

 and containing numerous granite fragments. Above the conglom- 

 erate is (3) limestone in considerable thickness, and over this (4) 

 the upper slate conglomerate. This last is a thick formation. The 

 upper conglomerate is very coarse near the limestone, and becomes 

 finer in passing away from the limestone along the lake shore. Like 

 the conglomerate near Garden River, it bears very numerous lime- 

 stone fragments, the evidence of which is beautifully seen at the 

 lake shore, where the water has dissolved many of them completely 

 and others in part. The ledge thus presents a deeply pitted surface, 

 many of the pits being several inches in depth. 



