326 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
high. The whole appearance at this place reminds one strongly of the 
alternations at the upper falls of the Montreal, on the South Shore,’ save 
that the beds are thinner on Temperance River than on the Montreal. 
The peculiar irregularities to which these eruptive rocks are subject 
were well seen in a cliff side 
below Temperance River, where 
‘ Fig. 28 was drawn. 
The ashbed-diabases of this 
group are only met with at low 
horizons, being found on the 
aa 
coast not far below Baptism 
River, and again at Grand Ma- 
rais. Immediately overlying 
BLY. the quartzose-porphyry of the 
> Lees Beaver Bay Group, C of Fig. 
Perse 
-) 
NS : : 
Ne fe 23, is found the succession 
indicated in the following dia- 
Fig. 28.—Section on Minnesota Coast, near Temperance 2’am (F ig. 29), in which the 
River. The columnar portions are the lower massive por- * A = 
tions of the flows; the dotted parts the amygdaloids or lowest lay te brown, ae ha 
vesicular upper portions of the flows. nitic diabase- porphyrite, with 
conchoidal fracture, and containing 52.56 per cent. of silica. The next 
is a black, medium-grained olivine-diabase or melaphyr, containing 50.76 
per cent. of silica, with the olivine wholly altered to a green and brown 
substance, and furnished above with an amygdaloid, and the uppermost 
Fic. 29.—Section on Minnesota Coast, near Baptisin River. 
layer is a heavy one of brown diabase-porphyrite, resembling that at the 
base of the section, but not quite so dense in grain, and carrying 57.87 per 
‘Geol. of Wis., Vol. III, p. 191. 
