548 THE GLACJIx^L LAKE AGASSIZ. 



NOTES OF ARTESIAN AND COMMON WELLS. 



The following notes present many sections, showing in detail the char- 

 acter and order of the drift deposits penetrated by artesian and common 

 wells in the Red River Valley and on the contiguous higher eastern and 

 western borders of Lake Agassiz. A few of these wells pass thi-ough the 

 di'ift and afford information of the underlying Cretaceous and Lower Silu- 

 rian strata. Among the many records of wells gathered during* the survey 

 of the shore-lines of Lake Agassiz, this list selects in general the most note- 

 worthy, as those remarkable for their depth, for abundant flow or sudden 

 rise of water, or for their sections of the drift and older formations. At 

 the same time the ordinary or average depth, or the range in depth of other 

 wells, and the quantity and quality of then water supply, are often stated, 

 with the prevailing character of the drift, lacustrine, and alluvial beds. 



Two classes of wells, peculiar respectively to the beach ridges and the 

 deltas, may be here described once for all, so that no examples of them will 

 appear in the following pages. Many farmers, in selecting the site for their 

 dwellings, have wisely placed them on the beautifully rounded, wave-like 

 ridges of gravel and sand which mark the former shores of Lake Agassiz. 

 Their houses have dry cellars, and their wells, after passing 10 to 15 feet 

 through the gravel of the beach to the underlying till, usually obtain an 

 ample supply of excellent water, healthful for people, horses, and cattle to 

 di'ink. The water is hard, or unfit for washing with soap, because of the 

 presence of the carbonates of lime .and magnesia dissolved from the gravel, 

 sand, and till; but it is usually free from alkaline matter, such as is often 

 contained in the Avater of this district when it has percolated through the 

 till and its inclosed sand and gravel beds for longer distances. 



On the deltas of Lake Agassiz wells also usually have water of the 

 same good quality, but it is found at a greater depth. Usually on these 

 tracts the depth to water ranges from 20 to 50 feet; but on the Pembina 

 delta and near the outer border of the Assiniboine delta a thickness exceed- 

 ing 100 feet in their porous sand and gravel deposits must be penetrated 

 before the plane of saturation or of water running through their basal 

 portion is reached. Along the foot of the frontal slope of the delta, or 



