644 EDWARD STEIDTMANN 



The youngest rocks of the region are basic dikes classed as 

 Keweenawan. 



Baker^ classifies the pre- Cambrian rocks of the Kingston area 

 in southeastern Ontario as follows: 



Great unconformity 

 Keweenawan — Trap, diabase, and gabbro intrusives 



Intrusive contact 

 Algoman — Coarse-grained granite and syenite intrusives with later pegmatites 



Intrusive contact 

 Laurentian — Gray to pink, medium to fine-grained, granitic gneisses 



Intrusive contact 

 Grenville — White, coarsely crystalline limestone with quartzite and rusty 

 weathering gneisses. 

 Dark green to black gneisses — thoroughly impregnated with minute 

 dikes of Laurentian granite, now also changed to gneiss. 



As reported by E. L. Bruce,^ the succession in the Cripple 

 Creek Gold district located about twenty-five miles southwest of 

 Porcupine, Ontario, is: 

 Glacial and Recent 



Peat, unsorted and more or less sorted sands and clays 

 Unconformity 

 Post-Laurentian 



Diabase dikes 

 Igneous contact 

 Laurentian 



Gray granite — reddish gneissoid granite 

 Igneous contact 

 Keewatin 



Greenstones, schists, diabase, and iron formation 



The Kirkland Lake and Swastika^ gold areas are located in the 

 Timiskaming district, fifty miles north of Cobalt. The pre- 

 Cambrian rocks are classified as follows: 



Later dikes — Diabase 

 Intrusive contact 



^ M. B. Baker, "The Geology of Kingston (Ontario) and Vicinity," Ontario Bur. 

 Mines, 25th Ann. Repi., Vol. XXV, Part 3 (1916), pp. 1-36, 19 figs., map. 



^ E. L. Bruce, geologist, and W. R. Rogers, topographer, "Cripple Creek Gold 

 Area, Ontario Bur. Mines, Vol. XXI (191 2), Part I, pp. 256-65, 9 figs. 



3 A. G. Burrows and P. E. Hopkins, "The Kirkland Lake and Swastika Gold 

 Areas, Ontario Bur. Mines, 23d Ann. Rept., Vol. XXIII, Part II (1914), pp. 1-39. 



