THE LOWER HURONIAN. 291 



eveu 80° to the south, although the steep northward dip is the one which 

 un questionably predominates. The sketch reproduced in fig. 19, which was 

 di-awn to scale in the field, illustrates very well the intricacy of the contact 

 between the sediments and the igneous rocks and shows other features which 

 at first tended to create a belief that the porphyry was in igneous contact 

 with the sediments. The exposure reproduced occurs on the hill at the 

 west side of the first bay west of the northeast point of Ely Island and on 

 the north shore of the island. Going along the contact between these rocks, 

 one finds the contact plane lying at different angles, but on this particular 

 exposure the folding has not been so great as to overturn the rocks and place 

 the conglomerate under the igneous rock. Just north of the first main fold 

 at the south end of the exposixres sketched are a number of very small 

 flutings, and one of these is represented as it occurs in nature — as connected 

 with the main mass of sediments merely by a small neck. A little farther 

 north of tMs place, on the hill, there was observed a small mass of con- 

 glomerate, represented in the sketch, which was completely separated from 

 the sediment and surrounded by the igneous rock. This evidently was 

 closely infolded in the igneous rock and afterwards sejDarated by erosion 

 from the main mass. Here the process of separation has been completed, 

 whereas in the mass previously described erosion had gone only far enough 

 to leave merely a narrow neck connecting- it with the main area. This 

 isolated area of conglomerate appeared much like an inclusion of con- 

 glomerate in the porphyry, and was so construed at first, but later more 

 detailed studies showed its true character as an infolded mass. 



On the east side of Stuntz Bay of Vermilion Lake the conglomerate 

 is well developed and is exposed over large areas having white weathered 

 surfaces. Here, as at the other places noted, the conglomeratic character 

 is plain, the fragments being well rounded and ranging from minute pebbles 

 to bowlders 2 feet or more in diameter. At one place there is a coarse 

 conglomerate made up of fairly irregular bowlders, such a conglomerate ixs- 

 is often deposited near a shore line on which the wave action has not 

 greatly rounded the fragments. Immediately in contact with this coarse 

 conglomerate is a belt, about 4 feet thick, of beautiful, regular conglom- 

 erate, such as would be produced by the consolidation of a shingle beach. 

 The majority of the pebbles of this bed vary from 1 to 6 inches in 

 diameter. The conglomerates have not been very much metamorphosed. 



