474 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr 
strata and the Laurentian; and I have succeeded in discovering in 
yarlous places :— 
Ist. The unconformable contact of the Lower Silurian gold-bearing 
strata with the underlying gneissoid and schistose series. 4 
2nd. The unconformable contact of this gneissoid and schiste- 
series with the old porphyritic gneiss which I had before deseribed 
as Laurentian. 
3rd. The unconformable contact of the gold-bearing series with 
the old Laurentian gneiss, showing the absence of the intermediate 
eneissoid series, or the Huronian. 
These several points of contact are visible at both extremities 
of a patch of Huronian strata about four miles broad, overlying the 
Laurentian on the Windsor and Halifax Railway, commencing one 
mile, or thereabouts, south-east of new Stillwater station, and ter- 
minating at Uniacke’s second lake, and more than half a mile west 
of Mount Uniacke station. 
VY. Tue LAURENTIAN SERIES. 
The rocks last described are visible, as already stated, in uncon- 
formable contact with a coarse porphyritic granitoid gneiss near 
Stillwater station. The strike of the granitoid gneiss is N. 10° W., 
dip W., at an angle of about 48°. Five miles further south, and 
within a third of a mile of Mount Uniacke station, the Silurian 
quartzites rest on the Laurentian gneiss, the quartzites having a 
strike N. 75° W., and the old gneiss N. 20° W. Between Stillwater 
and Mount Uniacke the Huronian series rests on the old gneiss, and 
the Silurian on the Huronian; but north of Stillwater and south of 
Mount Uniacke the Silurian strata are in contact with Laurentian 
gneiss, and so continue until another patch of Huronian is reached, 
this last named series appearing to cover comparatively small areas 
in the great Laurentian valley between Halifax and Windsor; but 
in the more western counties it is exposed, I have reason to believe, 
to a very considerable extent. 
In the county of Guysborough (fig. 4) the gold-bearing rocks at 
Sherbrooke rest on the Huronian, which, again, is seen close at hand 
in contact with the old Laurentian gneiss. In the middle and eastern 
part of Nova Scotia the thickness of the Huronian does not appear 
to be very considerable ; but no complete section has yet been crossed, 
except at Sherbrooke (fig. 5). Between Halifax and Windsor the 
Lower Silurian series occupies a great valley or synclinal fold in the 
old Laurentian gneiss. The average breadth of the valley is nine 
miles. Its general course is north-west (true); and the gold- 
districts of Mount Uniacke and Hammond’s Plains are arranged on 
its western boundary—and those of Lawrencetown, Montagu, Wa- 
verley, and Renfrew on the eastern boundary of the valley, occupy- 
ing crowns of anticlinals which have a general north-east-by-east 
direction (fig. 1). 
In one part of the county of Guysborough the Laurentian, with a 
narrow band (as far as known) of Huronian, forms a nucleus, haying 
