120 PROCEEDINGS OF THE AMHERST MEETING 



ment is really an epitaph over a buried investigation, the epitaph over a child 

 by its parent. In spite of his disappointment, he most loyally devoted himself 

 to the duties which Powell asked him to undertake, but he permitted himself 

 an expression of feeling in an annual report to his Director : "While I recog- 

 nize fully the considerations which led to the closing of this investigation of 

 the Great Basin, and while the wisdom of your decision is unquestioned, I yet 

 find myself unable to lay the work aside without the tribute of regret and the 

 expression of a hope that it may some day be resumed by another if not by 

 myself.'' 



Gilbert never had opportunity of returning to his Pleistocene studies in the 

 West ; but those of us who looked with admiration on what he did accomplish 

 and who looked with affection to him must rejoice that, if his wish to resume 

 the studies himself could not be gratified, his alternative wish, that they should 

 be resumed by another, is now about to be realized. 



18 THE CHANNEL OF THE MISSOURI R1TER THROUGH NORTH DAKOTA OF 



TERTIARY ORIGIN? 



BY JAMES E. TODD 



(Abstract) 



A few years ago the State Geologist of North Dakota published his conclu- 

 sion that the course of the Missouri was determined in Tertiary time and was 

 strictly preglacial. His reasons may be briefly stated as follows: (1) No 

 channels in that State have been found to run across the present course of the 

 Missouri toward the north and east. (2) Glacial boulders have been found 

 125 feet below the surface of a low terrace along the Missouri River near 

 Bismarck. (3) Glacial gravel has been found capping a terrace 55 or 60 feet 

 above the Missouri River, between Mandan and the mouth of Knife River. 

 (4) Between Sawyer and Price this terrace is capped with till 30 to 40 feet 

 thick. (5) A little below the mouth of Tobacco Garden Creek, on the north 

 side of the Missouri, is a mass of glacial boulders 12 feet or more in thickness, 

 which extends for a hundred yards along the river. 



To the first point it may be replied that he is evidently looking at too low 

 an altitude, and that it is possible for channels to be very thoroughly hidden 

 by a deposition of till. The valley of the Yellowstone, though just beyond the 

 west line of the State, has been traced over the divide to the Souris River, 

 and the valley of Long Lake may be readily shown to be possibly the pre- 

 glacial channel of the Cannon Ball River. The second point loses its value if 

 we remember the depth to which flooded streams may scour their channels. 

 When we remember the abundant water of Apple Creek, derived from the 

 ice-sheet a few miles farther east, it is not difficult to suppose that these large 

 boulders found their place on bedrock in the latter part of the Glacial period. 

 Third, the position of glacial gravel and boulders on the terrace above Mandan 

 may be similarly explained. Fourth, the occurrence of many feet of till on 

 the terrace is a good argument for supposing that the terrace was there when 

 the glacier passed over it ; for till is admitted to be a subglacial deposit. But 

 it may have been the valley of Knife River rather than the valley of the Mis- 

 souri. Fifth, the unusual deposit of boulders near Tobacco Garden Creek has 



