344 G. K. Gilbert— Outlet of Lake Bonneviile. 
straight, course across the country, ascending and descending 
slopes without change of direction. It is only by accident 
that it is ever horizontal. 
Wave terraces and delta terraces are associated phenomena 
of shore lines. They agree in the essential character of hori- 
zontality, and by that are distinguished from all other terraces. 
ey have no such relation to rock structure as have terraces 
by differential erosion. Their scarps are not of even height 
like those of stream terraces. Their course across the country 
has the sinuosity of a contour, and not the directness of a line 
of orographic displacement. 
valleys adjoin, the trough is restricted by spurs from the two 
ranges, and a few protruding crags show that there is a low 
cross ridge of limestone buried by more recent deposits. UR 
the west side of Cache Valley there is a low interval in the 
bounding range—so low that the Bonneville flood overtopped 
it and made Cache Valley a bay of the great lake. At th 
point Bear River has cut a narrow gorge, through which the 
draipage of the entire valley finds its way to the basin of Great 
Salt Lake. Bear River and several other streams enter Vache 
Marsh Valleys to the same level. Red Rock Pass was only 2 
See of stricture of the lake, and the outlet was at. the north. 
e mentions terraces in Marsh Valley and gives their altitudes, 
own observations, Cache Valley was occupied by Lake Bons’ 
ville, and Marsh Valley was not so occupied, but was traverse 
