240 B. N. A. BOUNDARY COMMISSION. 

colour from yellowish to dull bluish-grey, and with rusty cracks tra- 
versing it in many directions. It is usually so homogeneous, that on 
weathering it assumes vertical forms, and a rudely columnar appearance. 
It seems to have been moved, and to some extent stirred together after 
its deposition, and contains many glaciated stones and small boulders 
scattered irregularly through it, and resting in all positions. In some 
places, however, current structure and false bedding are very apparent. 
The included fragments are of the usual metamorphic rocks, and Quartzite 
drift, with some white limestone, and ironstone nodules, selenite, fossil 
Ostreas and Cephalopods from the Cretaceous. Lignite and coaly lignite, 
like that already described, are not uncommon. The appearance is that 
of very heavy ice action, and it would seem that a great part of the ma- 
terial has been derived from the underlying clays of Cretaceous No. 4, 
which have been poached up, without having been far removed, and 
mingled with travelled erratics. 
553. The valley of the West Fork of Milk River, shows some sections 
of similar clay. An examination of the superficial drift of this vicinity 
gave the following numerical result :-— 
1. Quarézite drifts, |. edi. bi, dos'd.5 ciliesicew 40.0. Saee See 52 07 
2 Granitic and gneissic rocks, of prevalent pinkish and greyish 
| i, re re Tre re 25 66 
BE DLAMOSGONE alo oo sso ec coscinss. 0 bie. cave iesb dy soln. ope s GLORIES 717 
4. Soft sandstone, clay-shale, &c., (local).......... : do.uaeieay 5 66 
& Orystalline quartins « <.a..d4isevecne sess onekepre eee 3°77 
6. Chert...... (ees dames e Oda waeen seeps | ee Dees Dee 2°64 
T< Tronstone, (local)... . s.vcas aisles secs te uu es 50s Sine Ree 1°88 
8... Porphyritac trap... 25.5.1 cawes > > caceay apne Spree eee 1 23 
554. The colours of the quartzite pebbles of No. 1, are generally yel- 
lowish, brownish and whitish, but among them have been included a few 
fragments of greenish slaty rocks, and many apparently intermediate 
between this and quartzite, but not clearly referable to either. The 
whole have therefore been placed under one heading, as probably 
derived from the mountains, though some—especially of the slaty sam- 
ples—may be Huronian. Among the limestone pebbles also, are one or 
two which resembled those of the mountains. It is interesting to find 
here a few specimens of the trappean rock of the nucleus of the Buttes, 
which are situated sixty miles due west. A fragment of an Ostrea was 
also found though not enumerated. : 
555. No instructive sections of the drift were met with in the vici- 
nity of Milk River. The surface of the plain is strewn with boulders in 
many places, but the drift deposits do not appear to be thick. Near the 
610 mile point, the plain has a general elevation of about 3,600 feet. An 
