346 DESCRIPTION OF THE COUNTRY 
fifty yards further, the basaltic bed is overlaid by siliceo-argillaceous shale (No. 404). 
At some points, it is highly metamorphosed and compact, but on exposure to the 
weather exhibits its schistose structure. It appears to belong to the same beds as 
No. 401. Some of the beds resemble altered sandstone, while other beds approach 
quartzite. 
Three hundred yards above the fall, this rock (No. 404) contains many large 
nests of minerals. These nests are from one to two feet in diameter, and contain, 
principally, calcareous spar and sulphate of barytes. The rock at these points 
seems to have been deposited around an original nucleus, as shown in the following 
figure. 
See 
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Just beyond the place where these nests first show themselves, the strata become 
nearly vertical, as shown at (8) in the section,* and exhibit the most undoubted evi- 
dence, in their extraordinary contortions and bendings, of having been subjected to 
ereat lateral pressure (Nos. 405, 406). The shales and schists are very thinly 
laminated, some of the laminz not being over an eighth of an inch thick. 
The rocks gradually become more and more altered, until they are intersected by 
a dike of trap, sixty feet in width, bearing northeast by north and southwest by 
south. In the immediate vicinity of this dike, the schists are very compact, and 
disposed to assume a columnar structure. Here, there is a fall of several feet. 
Above the ridge formed by the dike, the schists are of a grayish colour, free from 
flexures, and dip to the southeast at an angle of 20°. Rather more than a quarter 
of a mile higher up, the stream is crossed by a dike of No. 408, six feet wide, and 
bearing east-southeast and west-northwest. The shaly rock (No. 409) in contact 
with the dike is highly metamorphosed. About seventy-five yards further on is 
another dike, thirty-two feet in width, and bearing north and south. Between 
these dikes, the shaly rocks are of a yellowish-red colour. Sixty yards higher up 
is still another dike, fourteen feet wide, and bearing north and south. 
The space between these two last dikes is occupied by shales, so highly meta- 
morphosed, as to lose almost entirely their distinctive character. The last-men- 
tioned dike carries with it thin seams of calcareous spar and quartz. 
In contact with it on the west side, the rock resembles very much in constitution 
that of the dike, but a short distance off, it resumes the character of a metamor- 
phosed shale, and so continues until the beds become thicker, less shaly-looking, 
and finally compact. The lower beds (No. 410), are exceedingly hard and brittle, 
and break, without any regularity of fracture, into shapeless fragments. In some 
places it assumes a columnar structure, and resembles, in all its features, the quartz- 
ose porphyry of Wisacodé River; and other points further east. Its sedimentary 
character is conclusively shown by its containing rounded pebbles of other rocks. 
It is traversed by thin seams of calcareous spar. 
* See Section on the West Fork of Passabika River, (Pl. 3 N, Sect. 5.) 
