o 
Another irregularity comes in near the centre, in the form of large, 
eruptive masses interrupting the east and west trending schists and sedi- 
ments, the transverse band of batholithic granite called Tabletop being 
the most important. This mass, 14 miles long and 4 or 5 miles wide, 
marks the eastern end of the ancient schistose mountain core and indicates 
a great break in the structures where molten magma could well up. 
The huge uptilted slab, or perhaps syncline, of tough schist from 
2 to 8 miles across indicates a much more profound disturbance of the 
earth’s crust along the southwest curve of the mountains than the bands 
of old Palaeozoic sediments of the southeast; and the southward indentation 
of the bow shown on the geological map may indicate that the two halves 
were not formed by precisely the same thrust. Where the two thrusts 
met there was a transverse rent through which granite could ascend. 
RELATED PHYSIOGRAPHIC FEATURES 
When the Shickshocks wore in their prime, some time toward the 
close of the Palaeozoic, they formed a lofty chain of mountains comparable 
to the Rockies, and the basal structural features now evident, the core of 
schist and the central eruptive masses, were hidden under Silurian, Devon- 
ian, and peihaps later sediments. That the mountains were then much 
higher and much wider than at present seems certain from the existing 
river systems with their main watershed 10 miles south of the loftiest 
summits. The water parting probably occupied much the same position 
then as now, but with an elevation thousands of feet above the present 
watershed, since the northward slope must have been sufficient to pass 
over the present range when it was far higher. The absolute height one 
can only guess at, but the Tabletop batholith must have reached much 
above its present 4,350 feet and in addition must have been buried under 
a considerable thickness of non-conducting sediments to acquire its present 
granitic structure. To double its height would not seem unreasonable, 
so that the original range with its watershed some miles to the south may 
have reached 9,000 feet or more. 
As weathering and the general attack upon the mountain surface 
progressed, the more resistant core of schist and serpentine and granite 
became exposed, but strong rivers, such as the Cap-Chat and the Ste. 
Anne, carved their way down through them as fast as the watershed to 
the south was lowered and so preserved their grade toward the north. 
Ultimately the slowly yielding schists and eruptives became the highest 
summits and the relatively soft shales and sandstones were carved down to 
the present low tableland of southern Gaspe. The wild upper valleys 
of Cap-Chat and Ste. Anne rivers, cut down 2,500 feet below the mountains 
on each side, may be accounted for in this way; but the valley of Cas- 
capedia river, beginning in a lake 1,700 feet above the sea within a mile 
of the north side of the Shickshocks and flowing to Chaleur bay, demands 
some other explanation, probably the presence of an original depression 
leading southward. 
Until the present work was undertaken the highest points recorded 
in the Shickshocks (Figure 2) were mount Logan, 3,768 feet, and mount 
Albert, 3,560 feet; though the recently published topographic map indi- 
cates 4,000 feet over the area called “Tabletop mountains”. 
