
GLACIAL PHENOMENA AND SUPERFICIAL DEPOSITS. 241 
examination of the superficial drift at this place gave the following 
result :— 
emer sete OO IP ee 55°55 
2. Granitic and gnessic rocks, prevalent tint reddish, but much 
I od Fin six iain apie = ase « v'upis'o 4 ahead s 27°77 
P 3. Limestone, one fragment at least from the Rocky Mountains 6:11 
OS er ee reece eee ere 3°87 
5. Hard altered clay-rocks, yellowish, greenish-grey and 
DN Reds Gel thd SAR B 66 ois wihice w ors dd @ 0 wip ela 9 3°33 
ON a GI sete I clas ig a wis gis asia a < a'0'n M'o.0 » /jaimalaiens 2°22 
ee eS Ar er ee ere ees ree 0°52 
eI RR ia leit le cae, apn 5- 6 Ao ay afya see's Vein «ome 0°52 
An analysis by colour of the components of the Quartzite drift was 
also here attempted, and with the following result :— 
me Mile WEO WERE acts, 3.2 ow cigtiZae «aces'moe 4 deielejt <u<, 41°23 
MT NE SUES se gina ni aie ce ha K ei 'o we ade nea masa a\e 21°64 
Cee pre (IM Te ete aici tia we ei headc' a. wl alen evs 17°52 
White, or only slightly iron stained.............ceceseseees 15-46 
ES oy A Seg ts Bs Op a 3:09 
IN OR i ath hn RRL es pec enue d wes bie me's aye of 1:03 
The yellowish and browpvish specimens are as a rule very compact, 
though some are of coarse, granular quartzite. In the purplish and red- 
dish series, coarse-grained and compact varieties are about equally 
divided, and several of the greyish, are quite coarse-grained, the constitu- 
ent particles being of different coloured rocks. 
556. The Three Buttes, or Sweet Grass Hills, already briefly des- 
cribed in treating of their structure, yielded but few traces of action 
during the glacial period. Aware of the importance of these isolated 
mountains, I searched carefully for any glacial markings upon them, but 
the shattered nature of the hard rocks of their summits, and the softness 
of the strata flanking them, has prevented the preservation of such 
striation, if it originally existed. The terraced aspect of the foot-hills, 
though at first attributed to marine action; was afterwards found to be 
mainly, if not entirely, due to the arrangement of the subjacent rocks. 
The boulders of their immediate neighbourhood are frequently composed 
of the trappean rock of the summits, mingled largely with Laurentian 
and Quartzite erratics. A stream, flowing from the West Butte, at the 
foot of the steep slope of the mountain, has cut through a considerable 
thickness of rough, mostly angular, though not evidently glaciated stones, 
with which its valley had been filled. Of these the greater part were 
local and trappean,but some of foreign origin. Laurentian and Quartzite 
erratics are found in abundance to a height of over 4,000 feet. 
557. The main stream of trappean fragments, which, in whatever 
16 D 
