GEOLOGICAL EXPLORATIONS AND LITEIiATURE— 1S95. 147 



uucoufonnably deposited on tlie first could be observed" (p. 1). The 

 entire series of rocks observed in the district is classed as " Hurouiau." 



The granites and gneisses of the lowermost portion of the series are 

 now thought to have the characters of eruptive rather than of sedimentary- 

 rocks. A solid crust of granite served as the substratum on which the 

 Huronian beds were laid down, as is proved by the occurrence of belts of 

 granitic conglomerate and breccia in different horizons of the series. 



Two occurrences of these conglomerates associated with the granites 

 are particularly described, Adz, that in the SE. ^ sec. 22, T. 47 N., R. 26 W., 

 and that in the N. ^ sec. 29, T. 48 N., R. 25 W. The first locality furnishes 

 excellent proof of the correctness of the author's conclusion. Here are 

 several knobs with nuclei of massive granite sun-ounded by mantles of 

 coarse breccia, made of fragments of granite in a cement composed of well- 

 laminated quartzose material, and around these are hydromica-slates inter- 

 bedded with heavy belts of compact quartzite, which are conformable 

 with the breccia. At the second locality the conglomerate is interlami- 

 nated with diorite-schists, and is at some distance from any known outcrops 

 of granite. 



In the former report the author described a gradation of the granite 

 into quartzite. The outcrops thought to show this gradation were again 

 visited. The gradation rocks are now regarded as a mixture of granite 

 fragments and of sand material. 



Granite was upheaved, according to the author, and was intruded into 

 the overlying strata near the close of Huronian time, since it is found in 

 contact with all the Huronian strata up tcj the youngest, thouo-h inti-usive 

 belts of it are rarely found higher than the iron-bearing formation. More- 

 over, the beds in contact with the granite are always dislocated. The 

 dislocation, however, is not always due to the upheaval and intrusion of 

 the granite. It has been caused in part by diorites and diabases, which 

 intersect the gi-anite as well as the incumbent beds. 



The greenstones intersecting the granite are identical with those 

 intersecting the schists of the Huronian series, and with those interlami- 

 nated with these rocks. Their massive forms grade into greenstone-schists. 

 This fact led the author in his previous report to regard the diorites as 



