10 ILLUSTRATIONS. 
Page. 
Fig. 1. Map of crater rings near Cleft, Idaho 110 
2. Section showing relation of hillside springs to water table 149 
3. Section showing conditions favoring the occurrence of canyon springs. 150 
4. Section of an artesian basin 157 
5. Section of an artesian wedge 157 
6. Section of an artesian slope 158 
