350 



THE AZOIC SYSTEM AND ITS SUBDIVISIONS. 



junction of the Laurcntian and Iluronian in the Hudson's Bay district, 

 says : 



'' The junction of the two formations, which appear as usual to be conform- 

 able with each other, occurs juat where the southwest area opens into the main 

 body of the lake. Here the last of the Laurentian series consists of gray coarse 

 rough-surfaced quartz and mica-rock. The first rock on what is considered to 

 be the Huronian side of the boundary between the two series, consists of higldy 

 crystalline dark green hornblende schist, ribboned with fine lines of white 

 quartz grains. It is identical in character with the hornblende schist which 

 is usually found at the base of the Huronian bands in the region to the north- 

 Avestward of Lake Superior." {l. c, 21, C C.) 



It is now necessary to retrace our steps, and give some attention to 

 the Hastings or Montalban series in Canada. To these Mr. Murray 

 called attention in the Eeport of Progress for 1852-53, remarking : 



" In Huntingdon, Madoc, Marmora and Belmont, many interesting diversi- 

 ties occur in the Laurcntian series, but the rocks belonging to it become so fre- 

 quently and unexpectedly covered up by projecting and outlying masses of the 

 unconformable fossiliferous formations, in the part investigated, that it is as 

 yet impossible to give any connected view of their arrangement." {I c, 

 pp, 103-108.) 



In the Report of 1863 the rocks were again described (pp. 32, 33), 

 Dr. Hunt giving analyses of the limestone, as belonging to the Lauren- 

 tian (pp. 592, 593). 



In the Report for 18GG (pp. 91-113), the Hastings scries was once 

 more discussed by Mr. Thomas Macfarlane, who states tliat in the pre- 

 vious reports they have been shown to belong to the Laurentian. He 

 remarks that some of the conglomerates are " lithologically not unlike 

 some of the Huronian rocks," but does not appear to have taken ground 

 that this series of rocks was newer than the Laurentian, as Dr. Hunt 

 says he (Macfarlane) did (Azoic Rocks, p. 170). In the same Report 

 Logan stated that these rocks appeared to be conformable with the 

 Laurentian series, although they might be a higher portion of the scries 

 than had been met with elsewhere. (Z. c, p. 93.) 



In 18G7 Dr. Hunt stated that the Hastings series reposed in concord- 

 ant stratification upon the Laurentian gneiss ; but that tlie Upper 

 Laurentian or Labradorian reposed unconformably, not only on the 

 Lower Laurentian, but also upon the Hastings series. (E.^quisse Geolo- 

 gique (I Canada, pp. 5, 6). The same year Logan held that the '* inter- 

 ruption " of a limestone zone in the Hastings series by a labradorite 

 rock (gabbro, norite), supposed to be Upper Laurcntian, showed that 



