182 ROYAL SOCIETY OF CANADA 
place, near the Chats, it is overlaid by a considerable breadth of Huronian- 
looking rocks, schists, etc., which have been described in earlier reports 
under the name of Hastings series. The crystalline limestone portion of 
the Laurentian has its most westerly outcrop on the river in the vicinity 
of the Coulonge Lake, a short distance west of the Black River, the rocks 
further westward being for the most part granitic gneiss, granite and 
syenite, to the mouth of the Mattawa. In that portion of the Ottawa 
River section east of Ottawa city the limestones occur rather as separate 
bands occupying generally synclinals in the upper stratified gneisses, 
which form in many cases well-defined anticlinals, and in certain sections 
of this area these anticlinals are repeated very frequently, presenting thus 
the aspect of a ridged structure, in which the inclination of the strata is 
generally at a high angle. 
The rocks exposed along the route of the Mattawa and French rivers 
to Lake Huron are chiefly what have been regarded as Laurentian gneisses, 
There is, however, a general absence of crystalline limestones, which forms 
such an abundant constituent of the Laurentian further east ; and this, as 
well as the apparent inferior position of the gneisses themselves, caused 
them at an early date to be placed at the very base of the geological 
series, thus constituting the Lower Laurentian of Logan and other early 
Canadian geologists. 
Crystalline limestone is only very sparingly present in association 
with these gneissic rocks of the Mattawa section, and wherever noticed 
the evidence all seemed to point to the fact that it had béen “ caught up ” 
by the gneiss during the irruption of the latter. On the south shore of 
Talon Lake, as well as in the southern channel of the falls at the outlet of 
this lake, a crystalline limestone was noticed in conjunction with a very 
massive red foliated granite. Although in many places the bedding of 
this limestone corresponds with the planes of foliation of the inclosing 
rock, still at one place on the north bank of the river, a short distance 
above the falls, the limestone is seen to be in unconformable juxtaposition, 
the bedding of limestone abutting against the foliation of the granite. The 
line of junction is irregular and jagged, and the granite itself shows a 
much finer texture near the line of contact The limestone contains a 
good deal of serpentine in small spots and patches, and would form excel- 
lent building stone as well as good material for burning for lime. 
Crystalline limestone was also noticed on the east shore of the Great 
Manitou or Newman Island, in the eastern part of Lake Nipissing, as well 
as on two of the smaller islands composing this group. The limestone 
occurs associated with a massive red gneissic rock composed chiefly of a 
deep red felspar and a dark green chloritie material, the arrangement 
of the latter in approximately parallel bands and streaks, giving it a 
rather distinct foliation. The limestone is generally of a beautiful pink 
colour, and exhibits abundant small scales and erystals of biotite or 
