202 TRANSACTIONS OF THE™ [apr. 15, 
considered Etcheminian by G. F. Matthew* ; hence this diabase 
is post-Etcheminian, possibly Cambrian or later. 
Provisionally it may be placed as pre-Cambrian. 
The diabase is again well exposed on the west side of the har- 
bor of St. John, in a series of hills on the southeast border of 
the Cambrian valley. It is made up, as far as can be seen, of a 
number of surface flows, which are accompanied by a little slate, 
apparently interbedded, and were perhaps partly sbumariae. 
The characters of surface flows can be seen in some others of the 
many outcrops that occur in all parts of the Huronian hills, 
\\ : g ASS 
KOE 
= 
Fic. B. Vesicle in diabase, showing ayate-like banding of 
feldspar (?) and chlorite. Magnified 70 diameters. Spec. 150. 
others are more probably intrusive sills. All are normal dia- 
base, without olivine, and with an almost colorless augite. The 
vesicles are mostly lined with quartz, and filled with chlorite, 
sometimes with hornblende. The chlorite is very often spheru- 
litic and shows the beautiful Berlin-blue polarization color. 
Secondary growths of a mineral which seems to be plagioclase 
are known; it is not twinned, but appears to be sometimes opti- 
cally continuous with the feldspar rods around the vesicle. It 
* Trans. Roy. Soc. Canada, 1790, See. 4, p. 127. 
