THE COBALT SERIES; ITS CHARACTER AND ORIGIN 135 
the conglomerate was deposited was one of mature topography, 
so that the transportation of the large bowlders must have been 
effected by streams having gentle gradients. In order to explain 
this difficulty, it has been pointed out" that the climate of this 
Huronian period may have been semiarid and that during floods 
in regions where such climatic conditions prevail, bowlders of 
Fic. 3.—Scratched and faceted pebble from the conglomerate of the Cobalt 
series, occurring in Boischatel Township, Pontiac County, Quebec—a point about 
60 miles northeast of the Cobalt district. 
large size may be transported long distances by rivers. But it 
has already been shown from the character of the greywacke, 
argillite, arkose, and quartzite associated with the conglomerate, 
that the climate at the time these rocks were deposited was cer- 
tainly not arid and was probably humid and cold. Furthermore, 
t Ann. Rep. Bur. of Mines, Ont., XIV (1905), Pt. 2, p. 47. 
