128 MORLEY E. WILSON 
conformably by an upper conglomerate which differs in no respect 
from the lower member of the series and cannot be distinguished 
from it except where the stratigraphical succession is known. 
INTERFORMATIONAL UNCONFORMITIES 
In his geological report on the Cobalt district, W. G. Miller 
subdivided the Cobalt series into Lower and Middle Huronian,* 
but more recently? has adopted the name Cobalt series to include 
both these subdivisions. Miller’s classification of the Huronian - 
into two series was based on an unconformity between greywacke 
and arkose occurring, on lot 4, in the twelfth concession of Lorrain 
Township, Nipissing district, Ontario, where angular fragments of 
the greywacke are inclosed in an arkose matrix. Unconformities 
between a “‘greywacke conglomerate and an overlying arkose 
series”’ are also mentioned by A. G. Burrows in a marginal note 
on a map of ‘“‘part of the Gowganda silver area,” published by the 
Ontario Bureau of Mines, but no details as to the character of these 
are given. In one locality in the Larder Lake district the writer 
observed an arkose bed to contain fragments of an underlying 
argillite, but the fragments were irregular in outline and contained 
sand grains along their margin as if the argillite had been plastic 
at the time of its fragmentation. Fragments of a precisely similar 
character and in the same relationship have also been observed by 
W. H. Collins in the region north of the Sudbury district. With 
the foregoing exceptions, as far as has been observed, the various 
members of the series are in conformable relationship to one another# 
so that the unconformities that have been described are local and 
probably interformational in character and do not necessarily sig- 
nify a break of any importance in the continuity of deposition. 
DISTRIBUTION OF COBALT SERIES ' 
The Cobalt series is now known to occur in the Timiskaming 
region and vicinity throughout an area of approximately 20,000 
t Ann. Rep. Bur. of Mines, Ont. (1905), Pt. 2, pp. 40-42. 
2 Rng. Min. Jour., XCII (1911), 648. 
3 Personal communication. 
4 Sum. Rep. Geol. Surv., Dept. of Mines, Can. (1906), p. 117; ‘‘Geol. of an Area 
Adjoining the East Side of Lake Timiskaming,” Geol. Surv., Dept. of Mines, Can. 
(1910), p. 30; ““Prel. Rep. on Gowganda Mining Division,” ibid. (1909), p. 32. 
