TnE SAND HILL DELTA. 299 



of the river in its irregular course before they were deposited in Lake 

 Agassiz, where they at once settled to the bottom of the still water. 



Ill the south half of section 32, Gai-field, and in a belt which thence 

 extends approximately north and south, the surface of this delta, as it was 

 originally deposited, falls toward the west with a slope of 25 or 30 feet in 1 

 mile, from 1,125 or 1,130 feet to about 1,100 feet above the sea. Beneath 

 this plane, however, channels have Ijeen eroded by the winds, and sand hills 

 25 to 75 feet above it have been blown up in irregular groups and series, 

 scattered over a tract about a mile wide and extending 3 or 4 miles south- 

 ward from the Sand Hill River, in section 29, the northeast part of section 

 30, and in sections 31 and 32, Garfield, and reaching southward in sections 

 5 and 8, Sundal. The most southern of these hills is an isolated group 

 in the east part of the northeast quarter of section 18, Sundal. Another 

 isolated group lies north of the Sand Hill River, in the northwest quarter 

 of section 16, Garfield. These sand dunes are in part bare, being so fre- 

 quently drifted ]:)y the winds as to allow no foothold for vegetation ; other 

 poi'tions are clothed with grass or with liushes and scanty dwarfed trees, 

 including bur oak, the common aspen or poplar, eottonwood, green ash, 

 black cheiTy, and the frost grape. 



Elevations of the highest points of these dunes, in oi-der from south to 

 north, are approximately 1,190, 1,180, and 1,200 feet. The highest dune 

 appears to be in or near the east half of the northeast quarter of section 

 30, Garfield. 



Second? y Herman beach, a smoothly rounded ridge of gravel and 

 sand 10 to 15 feet high above the adjacent level, 1,148 to 1,153 feet above 

 the sea, about three-fourths of a mile east of the old Pembina trail, in the 

 west half of sections 21 and 16, Garfield, extending li miles north from 

 the Sand Hill River to the cluster of dunes in the northwest quarter of 

 section 16. 



VICINITY OF MAPLE LAKE. 



(PLATK XXVI.) 



The upper Herman beach, the first of the series which was formed in 

 the \'icinity of Ma[)le Lake contemporaneously with the single Herman 

 beach farther south, runs approximately from south to north, through or 



