55

Lithology.

The Haida formation is largely composed of sandstones,
though many beds of shale occur in some localities, and strata
coarse enough to be called conglomerate or breccias are found.
The basal beds are well exposed at Haida point, the east end of
Maude island, and at other localities in Skidegate inlet. They
are pale yellow and buff, coarse sandstones and fine conglomerates
largely quartzose, and containing in varying amount angular
and subangular fragments of the Yakoun volcanics. Carbonized
stems of trees, partly replaced by calcite, and bits of bright,
coaly matter up to several inches in diameter are not uncommon
near the base. Higher in the formation, in the exposures on the
shores of Bearskin bay, are green chloritic and feldspathic con-
cretionary sandstones, in massive layers, containing fossil
pelecypods and ammonites in abundance. These sandstones
exfoliate in scaly sheets. Dark-grey, very fine, thin-bedded,
argillaceous sandstones, to which the term shale may be applied,
outcrop between Queen Charlotte, and Lina narrows. With
these are associated buff-weathering hard, dense, calcareous,
siliceous, and ferruginous concretionary bands.

Inland, especially near Camp Wilson and on the Tlell river,
the lowest beds are composed of re-sorted, angular fragments
of the Yakoun volcanics, in a matrix of similar, finer material,
so that it is frequently difficult to tell the Haida beds from the
rocks on which they lie.

In the Slatechuck valley there are thick beds of black very
fine-grained, massive, hard shale, which is highly carbonaceous,
and breaks with a conchoidal fracture. It is used by the Haida
Indians for carving small models of totem poles and other
distinctive ornaments. This shale is very like that in which the
coal seams in the Slatechuck valley are found.

This rock was analysed by B. J. Harrington! from samples
collected by Mr. Richardson in 1872. The analysis follows:

SiO; A1.03 FeO; CaO MgO H.0
44-78 36-94 8-46 trace trace 7-15
Carbonaceous matter—3: 18 = 100-51

1 Geol. Surv., Can., Rept. of Prog., 1872-73, p. 62.