PRE-CAMBRIAN LITERATURE OF NORTH AMERICA 651 



Collins' reports on the Onaping map area about fifty miles 

 north of Sudbury. Following his former practice, he divides the 

 pre-Cambrian rocks into Huronian and pre-Huronian. His table 

 of pre-Cambrian formations follows : 



Huronian — Keweenawan Olivine diabase 

 Basic intrusives? Quartz diabase 



Quartz norite and intermediate varieties 

 Intrusive contact 



Cobalt series — Upper white quartzite 



Banded cherty quartzite 

 Lorrain quartzite 

 Gowganda formation: 

 Conglomerate 

 Graywacke 

 Limestone 

 Great unconformity 

 Pre-Huronian 



Batholithic intrusives — Granite gneiss and its differentiates 

 Schist complex — Altered volcanic and intrusive rocks, iron forma- 

 tion, and other sediments 



P. E. Hopkins^ reports the succession in ]Mc Arthur township of 



the Porcupine Gold Area as 



Late intrusives — Diabase 

 Timiskaming ? — Slates 



Laurentian — Granites intrusive into Keewatin 



Keewatin — Greenstone, serpentine, hornblende schists, porphyries, carbon- 

 ates, and chert magnetite iron formation 



Hopkins^ reports on the Beatty-Munro Gold area in the Larder 

 Lake mining division of Ontario, latitude 48° 30', longitude 80° 15'. 

 The rocks are all pre-Cambrian and are classified by Hopkins as 

 follows : 

 Post-Timiskaming intrusives — Feldspar porphyry dikes 



Intrusive contact 



Diabase dikes and stocklike masses 



Intrusive contact 



^ W. H. Collins, "Onaping Map Area (Ontario)," Canada Gcol. Surv. Mem., No. 95 

 (191 7), 157 pp., II pis., 8 figs., 2 maps. 



^ P. E. Hopkins, "Xotes on McArthur Township," Ontario Bur. Mines, 21st Ann. 

 Kept., Vol. XXI (1912), Part I, pp. 27S-80, 2 figs. 



3 P. E. Hopkins, "The Beatty-Munro Gold Area (Ontario)," Ontario Btir. Mines, 

 Ann. RepL, Vol. XXIV (1915), Part I, pp. 171-84, 9 figs., i map. 



