DISLOCATION AT SALT SPRING. 95 
of the most interesting geological sections met with on our route. Travelling from the west 
upon the Cretaceous strata, for some miles lying nearly horizontal, we came suddenly, and 
without preparation, to a wall from three to five hundred feet in height, of which the western 
face, inclined to the horizon at an angle of 70°, is formed by the same stratum as that on 
which we stood. Passing through an avenue opened in this wall by a stream, we found it to be 
a huge fragment of the rocky basis of this region, broken up from its connexions, and set 
nearly at right angles to its former position. All the stratified rocks exposed about Fort Defi- 
ance are here represented, parallel among themselves, but nearly vertical; presenting in the 
sides of the gap through which we passed a very perfect and instructive horizontal section. 
This wall here runs dam-like across a valley of considerable width, and, strongly relieved from 
the level surface on either side, it is one of the most impressive examples of dislocation I have 
ever seen. 
Fig, 27,—SECTION OF DISLOCATED STRATA AT SALT SPRING. 
Het ny 
/ ' lo 
tea Mi 
t 7 
Hn Aigyyy ; 
; ini! Mit ee Nig Bi) 
iy Hy 1; 3 piherte 
pen perth 
TE i fe 
b é 
{ Chalk series; 
& Upper part of the Lower Cretaceous formation, 
a Lower Cretaceous sandstone shales. 
6 Variegated marls and red calc. sandstone 
¢ Soft variegated marls with magnesian limestones and silicified wood. 
d Green and red sandstones and shales —-Salt Group. 
| Variegated marls. 
The convulsions which have shaken this vicinity are not alone attested by the upturned mass 
just described, for a different geological horizon is presented on its eastern from that on its 
western side. In our approach to it, for many miles, nothing had been visible but the upper 
portion of the Cretaceous series, but, issuing from the passage cut through it, we found our- 
selves in a broad valley, bounded by bluffs of great height, in which appeared all the strata 
we had observed in this region. The bottom of this valley is composed of the upper strata of the 
Saliferous sandstone group, above which are the variegated marls and the red and white cal- 
careous sandstones, the latter presenting mural faces of several hundred feet in height. Upon 
these, more than a thousand feet above the valley, the Lower Cretaceous sandstones appear, 
forming a distinct mesa wall. From this description it will be seen that at the same absolute 
level we were, on the western side of the wall, geologically nearly two thousand feet higher 
than after passing it. 
Where the bluffs approach this transverse barrier on the north side of the valley I could 
perceive that the strata were bent down towards the corresponding ones in the dismembered 
portion, while toward the northeast, after rising rapidly for a short distance, they begin to dip 
in that direction. This would seem to indicate that in the action of the forces by which this 
displacement of the strata was produced they were raised into an immense arch, of which the 
curvature became too great for its tenacity, and a double line of fracture was produced. | 
portion of the arch which was included between these two lines still stands as the wall I have 
described. 
From Salt Spring to and through Campbell’s Pass the geology of our route included little or 
nothing new. We were constantly passing through a broad valley of erosion, bounded by 
precipitous and most picturesque cliffs of the variegated marls, and the red calcareous sand- 
