2 
A NEW CANADIAN OCCURRENCE OF PHOSPHORITE FROM 
NEAR FRANCOIS LAKE, BRITISH COLUMBIA 
The first two lots of the original phosphorite specimens were sent to 
the Geological Survey simultaneously by J. D. Galloway, now Provincial 
Mineralogist, Victoria, B.C., and by Mrs. 0. Collier, Francois Lake, B.C. 
Later on, Mr. G. Hanson collected a large specimen which is represented on 
Plate I. Recently the writer has received, for museum purposes, half a ton 
of selected material from Mr. E. M. Dotson, Frangois Lake. 
The outcrop from which these specimens were derived is on the farm 
of Mrs. Collier and about 1,000 feet from her house. The farm is 2 miles 
northwesterly from the ferry-landing on the north side of Frangois lake. 
The ferry-landing is 14 miles by motor road from the town of Burns Lake 
on the Canadian National railway. The discovery is credited to Mr. E. N. 
Dotson, a brother of Mrs. Collier. 
The phosphorite occurs as a small, irregular vein 4 to 12 inches wide, 
which outcrops at intervals for a distance of about 100 feet. The vein is 
almost horizontal and probably does not extend far either in length or 
width. The vein material, which is partly black and partly brown, con- 
sists of botryoidal phosphate associated with some asphalt and brecciated 
andesite. 
The geological information regarding Lake Frangois district can be 
summed up very briefly. G. M. Dawson 1 made a geological reconnaissance 
of Frangois lake and the area to the south in 1876, and J. D. Galloway, 2 
who collected the vein matter for the present study, made a brief examina- 
tion in 1923 and again in 1924,® in company with G. Hanson. 
The following account of the mineral occurrence is from the cited 
report by Hanson . 
In the vicinity of Burns and Frangois lakes, the predominant rocks are frag- 
mental and massive volcanic rocks of the Hazelton group (Jurassic). .... tin con - 
formally on this older basement rest isolated patches of Tertiary sediments and lava 
flows. The Tertiary rocks were noted especially in the vicinity of Frangois Lake post 
office, where basaltic lava flows, 100 feet thick, apparently overlie conformably soft, 
sedimentary rocks. Fossiliferous sediments are present along the northern shore of Fran- 
cois lake. The Tertiary rocks do not appear to occupy extensive areas, and the formation 
is probably only rarely over 200 feet thick. Fossils .... from these rocks on the 
northern shore of Frangois lake .... have been examined by W. A. Bell .... (who 
concludes that the formation is) of Upper Eocene age. (The country rock of the vein 
holding phosphorite, etc.) is basaltic lava, 100 feet thick, and apparently overlies Tertiary 
sediments .... The .... vein lies between basalt walls and has a gentle dip parallel 
to the dip of the lava flows The wall-rock is rather friable, and the vein has the 
appearance of a filling between two flows of lava rather than the filling of a fracture. The 
possibility is also suggested that the material which gave rise to the phosphate minerals 
and bitumen accumulated on the surface of one lava flow and was covered by a later lava 
flow. The phosphate minerals and bitumen may have resulted from guano by a process of 
distillation in situ occasioned by the heat of the lava. 
Galloway states 4 that the occurrence is vein-like 
and may represent a 
cooling fracture in the Volcanic roek. It is apparent that the fracture was first partly 
filled with the brown mineral (phosphate) : later the asphaltum in a liquid or semi-liquid 
condition penetrated along the fissure and in places the brown mineral is soaked and 
iDaweon, G. M.: Geol. Surv., Canada, Rapt, of Prog. 1876-77, pp. 17-94 (1878). 
*Galloway, J. D.: Ana. Kept., Minister of Mines, B.C., 1923, pp. 119-118 (1924); 1924, pp. 101-104 (1925). 
•Hanson, George: Geol. Surv., Canada, Sum. Kept, 1924, pt. A, pp. 42-43 (1925). 
Ann. Rept., Minister of Mines, B.C., 1923, p. 117 (1924). 
