Variolitic Pillow-Lara. — Daly. 67 
underlying formation. The latter consists of black and dark- 
gray slates with alternating dark gray sandstones and grits 
which form part of the normal sedimentary series underlying 
islands and mainland. In these no fossils were to be found but 
the formation is doubtless part of a lower Palaeozoic terrane 
and perhaps equivalent to the Cambrian across Belle Isle 
Strait. 
Overlying the slates and in visible contact with them, is a 
conformable bed of light gray lava varying from 0.9 meter 
to 1.2 meter in thickness. This is an aphanitic rock in which 
the microscope shows evidence of very thorough alteration. 
A colorless, isotropic base seems to represent original glass. 
Within it are small, triclinic, polysynthetically twinned feld- 
spars which are rather vaguely crystallized, with a character- 
istic poor development of the twinning trace. No other orig- 
inal material appears in the thin section. Both glass and feld- 
spar are largely replaced by secondary matter which may have 
been derived also from pyroxene or other bisilicate pheno- 
crysts. No trace of the latter nor of an iron ore lias been 
found. Both the feldspar and isotropic base are shot through 
with needles of colorless to pale green actinolite, and are also 
replaced by chlorite, yellow epidote, zoisite and most abundant 
calcite. The whole forms a good example of an almost com- 
pletely altered lava which nevertheless remains tough and 
relatively hard. The very poor preservation of the feldspar 
prevents sure identification of the particular variety present 
but it is probably basic andesine or labradorite.' The rock may 
have been of a type intermediate between tachylite and normal 
basalt ; it is vesicular at both upper and lower contacts. 
Immediately above the lava sheet is the pillow lava, proved 
to be about 60 meters in thickness, and, in its turn, the pillow- 
lava is overlain by black slates, a narrow band of which appears 
at the water's edge just inside the entrance to the harbor. 
(Fig. 2.) 
All these comformaible beds have shared in the general moun- 
tain-building processes that have affected northern Newfound- 
land. With unusual distinctness of the slates about the harbor 
display a discordance between stratification dip and cleavage 
dip. At the sea-chasm referred to the two structure- seem t<> 
have a common strike of about X 2=r E, a direction nearlv 
