67 
1915-16.] The Origin of Oil-Shale. 
encountered. There are no branch veins of any importance, but numbers 
of minute veins of an inch or less in thickness. The workings have been 
closed for some years, but several tunnels driven across the strike from the 
surface can be entered and examined so that fairly complete knowledge of 
the structure and the country rock can be obtained. 
The shales surrounding this intrusion of albertite as far as it has been 
worked, and in every surface opening, outcrop, or exploratory tunnel, are 
practically all oil-shales. That is to say, a mass of strata 3000 feet in 
length by about 1000 feet broad, and proved to a depth of 150Q feet, is oil- 
S. N 
Unconformab/e 
C/pper Ser/es 
B/ bum /nous 
S an c/sbon es 
ALBEGT/TE 
lfe/ns 
Fig. 6. — Diagrammatic Section through Albert Mine, New Brunswick. 
shale — not shales impregnated with petroleum as in the case of Trinidad 
and Barbados manjak-fields, but true oil-shale full of “ ker6gen,” and with 
little or nothing soluble in organic solvents (2*3 per cent, is soluble in 
petroleum spirit). Though all the strata contain kerogen, some bands are 
richer than others, and yields of from 27 to 48 gallons per ton have been 
given in the experimental retort of the Pumpherston Oil Company. It is 
usual to distinguish two types in this mass of shales — the “ paper shales ” (a 
brown shale so fissile that it almost resembles mica), and a more massive and 
darker variety which shows faint “ curly” structures. The latter type is 
distinctly sandier and more gritty to the touch, and it gives a higher yield 
