3 



place in the earth's crust. These were entirely 

 independent of grlacial forces, and if it is 

 found that in other parts of the earth's s^ir- 

 face independent crustal movements were 

 going on at this time it will afford an addi- 

 tional explanation of the rise toward the 

 north of these remarkable beaches. 



THE WESTERN LAKE SASKATCHEWAN. 



But while the great northern glacier was 

 thus withdrawing and giving its waters to 

 Lake Agassiz, to the west of it, oeyond the 

 barriers which held it in, other areas were 

 being formed. As seen in fig. 1, an arm of 

 Lake Agassiz ran up the Saskatchewan valley 

 as far as the Elbow. Into the west of this, 

 which is called the glacial Lake Saskatche 

 wan ran the North Saskatchewan River, and 

 into the southern end the South Saskatche- 

 wan. The Pasquia hills were the southern 

 barrier for the lake. 



LAKE SOUKIS AND THE QD'APPELLE EIVEK. 



West of Turtle Mountain, which is found 

 in fig. 1 en the international boundary and 

 the Tiger Hills, was the glacial Lake Sjuri.s, 

 also represented in fig. 1. From the south- 

 west mto this emptied what is now the upper 

 part of the Souris River, Into the northern 

 arm of this Lake Souris poured the upper part 

 of the Assiniboine River, while into the west 

 side flowed the mighty river that came down 

 the Qa'Appelle valley. This Qu'Appelle River 

 was at that time running out of the 

 southern end of Lake Saskatchewan from 

 the point we now call the Elbow, 

 down the easily traced channel that leads into 

 the great valley with its overhanging heights, 

 the wonder of all visitors to the Qu'Appelle. 

 Lake Souris had on our side of the boundary 

 line effluents carrying its waters into Lake 

 Agassiz. These were the Pembina river, 

 which ran down the great gorges now so easily 

 traced from the elbow of the Souris river, 

 through Lang's valley. Pelican lake. Rock 

 lake and Swan lake to the crest of Pembina 

 mountains, where it emptied into Lake 

 Agassiz. At a later period, at a point farther 

 north, the Assiniboine river drained, as we 

 shall see. Lake Souris into Lake Agassiz. 



LAKE AGASSIZ EMPTIES NORTHWARD. 



At length as the great ice belt receded to 

 the north, the escaping waters ceased to find 

 their way into Lake Traverse and the Missis 

 sippi. Northward channels to the sea of 

 Hudson Bay were being found, though not 

 those now followed by the Nelson river and 

 its tributaries. During this northward fl.DW, 

 beaches continued to form on the shores of 

 the lake as it sank from stage to stage. 

 There are eleven of these that can be clearly 

 traced in our territory. 



MANITOBA BEACHES. 



We may follow the course of one or two of 

 these beaches by way of illustration, and 

 thus be able to see the diminishing area of 

 Lake Agassiz. One of them called the 

 Gladstone beach crosses the International 

 boundary line one and a half miles west of the 

 Mennonite village of Blumenort, is again 

 seen a mile east of Carman, crosses the C. P. 

 R. near the Rat Creek bridge west of Burn- 



side, and is traced half a mile east of Glad- 

 stone, being here found to measure 868 feet 

 above the sea. Another notable ridge is that 

 called the Stonewall beach. The main street 

 of Stonewall crosses this beach. The sand 

 and gravel at this point are only ten feet deep 

 above the underlying limestone, which here 

 rises in a swell above the surrounding country. 

 Mr. Upham says : — 



"Lake Agassiz, at the time of the Stone- 

 wall beach formation, probably extended on 

 the flat Red river valley to a distance of about 

 twenty-five miles south of the international 

 boundary, being some fifteen feet deep at 

 Emerson and Pembina, while over the site of 

 Winnipeg its depth was about sixty feet." 



The Morris beach is found about one mile 

 east of this town, which is forty miles south 

 of Winnipeg, crosses northwest to Starbuck, 

 then northeast to Little SSony Mountain, 

 passes between Stonewall and Stony Moun- 

 tain, and then north along the west side of 

 Lake Winnipeg a few miles from it. 



TWO GREAT DELTAS. 



When Lake Agassiz was in its higher stages 

 the rivers running out of Lake Souris as shown 

 in map 1, emptied the waters of the latter 

 lake into the former. And just as we see Red 

 River at the present time carrying its clayey 

 sediment to slack water at Lake Winnipeg 

 and depositing it in a delta, or as on Lake of 

 the Woods the Rainy river brings down vast 

 quantities of sand, which have been spread 

 over the bottom of the southern half of the 

 lake, and have formed along the shore thir- 

 teen miles of great sand hills or dunes, so the 

 ancient tributaries of Lake Agassiz formed in 

 the region of Manitoba two great deltas. To 

 these we owe the sandy deposits along the 

 boundary line made in the slope of the Pem- 

 bina Mountains and the very marked feature 

 of the country known as the sand hills west 

 and south of Portage la Prairie. 



THE PEMBINA DELTA. 



Lake Souris, as mentioned, originally empt- 

 ied its waters down Lang's valley and through 

 several enlargements, and tumbling over the 

 Pembina mountain the waters deposited their 

 sandy freight in a delta extending twelve miles 

 from north to south, and seven from east to 

 west, to a depth of 200 feet. This lies mostly 

 to the south of the Pembina river valley, as it 

 is seen at present. The material of the delta is 

 mostly sand and gravel, the gravel being 

 chiefly limestone, but much of it is Cretaceous 

 shale and of granitic and gneissic origin. The 

 formation of the delta seems to have been very 

 rapid and it trust have accumulated in sand 

 dunes fifty feet above the surface of Lake 

 Agassiz. But soon the ice sheet receded and 

 allowed Lake Souris to empty itself by way of 

 the Assiniboine into Lake Agassiz, when the 

 water ceased to follow Lang's valley and the 

 period of formation of Pembina delta ceased, 



THE ASSINIBOINE DELT.* . 



Few travellers on the C.P.R. from Portage 

 la Prairie to Brandon but have noticed the 

 remarkable range of sand hills thrcUj^h which 

 the railway cuts its way. Many speculations 

 have been indulged in as to their origin and 



