472 TERENCE T. QUIRKE 
conglomerates of Murray are so much alike that they cannot be 
distinguished. Where the limestone band is absent, as it often is, 
they join, and Murray himself confesses that he could not draw the 
dividing line.’”’ Nevertheless, in some such places the dividing 
line may be, and has been, drawn. On the other hand, there are 
phases of the Bruce conglomerate so similar in character to phases 
of the Cobalt conglomerate that no distinctions have yet been 
recognized. Another factor which may have caused confusion 
in the reports of Coleman is the fact that he found at Cobalt the 
Cobalt conglomerate to be the basal conglomerate of the Huronian 
formations, the entire Bruce series being wanting. Thus, carrying 
his correlations westward from Cobalt, he supposed the basal 
conglomerate of the original Huronian area to be the same as that 
at Cobalt, whereas it is actually the base of the Mississagi formation 
of the Bruce series. However, all this was clearly put straight by 
Collins in 1916, and it seems a pity to have confusion again after 
the known facts have been published. So far as is now known, 
the Bruce conglomerates, certainly for the main part, are not of 
glacial origin, but some of the Cobalt conglomerates are agreed to 
be tillites. 
Regarding the last topic, the work of the writer carried on this 
summer near Lake Geneva, 20 miles northwest of Sudbury, Ontario, 
shows that syenitic masses intrude the Cobalt series, thus confirm- 
ing and complementing the work of Collins (1916)? on the age of 
the Killarney granite. Collins found that the Bruce series certainly 
and possibly the Cobalt formations, are intruded by an acid intru- 
sive in an area north of Lake Huron, from 15 to 25 miles southward 
from Sudbury. Now it is known that what might have been con- 
sidered a local phenomenon of little consequence in pre-Cambrian 
classification and correlation must be regarded as probably a 
widespread and considerable intrusion. The age of these intrusions 
having been determined and confirmed in areas 40 miles apart, 
it becomes necessary to scrutinize carefully those local correlations 
and distinctions which are based largely upon different periods of 
orogenic movement and acid intrusions. Almost certainly it will 
1 W. H. Collins, Canada Geol. Survey, Mus. Bull. No. & (1916). 
2 Ibid. No. 22 (Feb. 5, 1916). Quoted by Steidtmann, op. cit., p. 650. 
