118 ROYAL SOCIETY OF CANADA 
East of this the fracture apparently dies out in the lower division of the 
Chazy formation. 
West of Pakenham the line of fracture extends in two directions. 
One of these continues along the northern flank of the main mass of 
the crystalline rocks, in which red granites are prominent, to the south- 
east corner of the township of MacNab. By this fault the underlying 
formations from the Black River to the Potsdam are cut out. The other 
line of fault, west of Pakenham, traverses the central portion of Fitzroy 
township, and brings the Black River limestones against the Calciferous. 
This continues also westward and may probably be found about one, 
mile and a-half south of Sand Point, which is five miles west of Arn- 
prior. It cannot however be definitely traced owing to the covering of 
drift. ; 7 | 
Near Pakenham also a third fault which is apparently more local 
in character, follows the course of the Mississippi river towards Almonte, 
and can be traced for several miles in this direction. This affects only 
the Chazy and Calciferous formations. 
Further west along the valley of the Bonnechère river, in the 
vicinity of the town of Eganville, other well-defined faults occur. These 
affect the rocks of the Chazy, Black River and Trenton formations only, 
but their tracing is rendered difficult from the paucity of exposures, 
owing to the covering of drift. 
In the area bordering on the St. Lawrence river, east of Brockville, 
the rocks are mostly of Calciferous age, ‘with a passage upward into the 
Chazy some miles west of the town of Cornwall. The upward passage 
to the Utica is apparently quite regular. The measures are affected by 
low undulations, but if faults exist in the district their extent must be 
quite limited since the strata are, as a rule, in a nearly horizontal posi- 
tion or affected by but slight dips. Owing to the fact however, that over 
large areas the drift covering is very heavy, such lines of fracture may 
exist, though their presence is concealed. 
The presence of the several lines of fault in the area south of the. 
Ottawa, and their association with intrusive rocks some of which are 
undoubtedly of comparatively recent date, as is the case with those of 
Rigaud mountain, open up a somewhat interesting problem as to their 
cause. On the hypothesis, now very well established, that the group 
of eruptive masses seen near Montreal and at points throughout the 
eastern townships of Quebec belong to the same period, viz., during or 
slightly subsequent to the deposition of the associated Devonian rocks, 
the limit of the inquiry becomes somewhat narrowed. That a great 
period of upheaval and displacement occurred subsequent to the deposi- 
tion of the Devonian limestones of eastern Quebec is manifest from the — 

