346 C. A. FISHER GIAXT SPRINGS AT GREAT FALLS, MONTANA 



nndergroimd j^assage of the water, but no positive evidence of this was 

 seen. "\Yell borings in lower Sand coulee and Gibson flat demonstrate 

 that the materials filling the old valley are largel}^ coarse river sedimenis 

 well adapted for rapid percolation of water. 



From the above it is readily seen that along the supposed underground 

 course of the Avater from the mouth of Sand coulee to where it appears 

 at the surface as springs, the physical conditions are such as to permit the 

 passage of a large volume of water, an amount believed to be equivalent 

 to that furnished by the Giant springs. 



