37

“Tts uses are confined to the manufacture of common building brick
and field drain tile, but it would require the addition of 20 to 30 per cent
of sand in order to reduce the shrinkages.

“The sample submitted by Mr. Harris is practically the same kind
of clay as that at Smithers. It would be suitable for making common
brick if sand could be found convenient to the deposit. The addition of
not less than 25 per cent of sand would be required for brick-making.”’

SAND.

Near Hazelton, on the north bank of the Bulkley, just east of the
bridge, there are terraces of well-assorted sands, but no detailed examina-
tion has been made of them.

TRAVERTINE.

Just above Twomile townsite, along Twomile creek, there are deposits
of travertine where the groundwater has oozed out of the clay or formed
springs; the lime carbonate is very pure in places and gives the appearance
of extensive beds, but it is very probably of shallow depth, merely an outer
coating on the clay and grading into the ordinary boulder clay of the
district. The groundwater in passing through material containing calcium
minerals has become highly charged with lime which was precipitated as
the carbonate when the waters reached the surface.