GEOLOGICAL INTEllEST NEAR MEDICINE HAT. 151 



of 800 feet above sea level and embraces an area of 6,900 square 

 miles. Being the last of that country to emerge from water, it has 

 received the drainage of the North-west for countless years and has 

 thus become em-iched by an alluvial deposit of almost inexhaustible 

 fertility. 



Some sixty feet beneath the surface solid rock is reached, but in 

 some places, Selkirk, Stony Mountain and Lake Winnipeg, the 

 rock reaches the surface and is usually a magnesian limestone, 

 rich in fossils belonging to the Silurian period. 



SECOND PRAIRIE STEPPE. 



This is well marked off from the j)recedino- by the Pembina 

 Riding and Duck Mountains, along its eastern side ; it has an 

 elevation of 1,600 feet above the sea, is about 260 miles wide at its 

 southern limit and narrows slightly towards the north. Within 

 this large area, arc 10,500 square miles of land more rolling in 

 character than that of the former district, but also containing 

 extensive stretches of prairie land. 



The underlying deposits here differ from those of the Eed River 

 Valley, both in character and age. In this area you find Cretaceous 

 clays, some bearing very interesting fossils, while in the preceding, 

 Silurian limestones characterize the deposits. 



THIRD PRAIRIE STEPPE. 



The so called Dirt Hills indicate the eastern limit of a vast region, 

 some 465 miles wide on the forty-ninth parallel, with an elevation of 

 3,000 feet above sea level and embracing some 1 34,000 square miles. 

 In this immense ai'ea are located the vast coal fields of the North- 

 west ; here too, we find the localities, that are to occupy our attention 

 to-night. The underlying deposits of this region are also Cretaceous, 

 the surface is more rolling than in the other steppes referred to, and 

 in many places lakes and ponds occur with waters strongly alkaline 

 As this great scene sweeps before us showing in succession these 

 marked natural steps, each full of interest, we can readily perceive 

 what an attractive country the North-west is to a student of geoloo-y. 



The rich ores of the Laurentian rocks to the east, the level lands 

 of almost exhaustless fertility in the Red River Yallev, the rolling 

 districts of the second plateau, with a drier and warmer soil and the 



