180 GUIDEBOOK OF THE WESTERN UNITED STATES. 
(left) as he approaches Delta. This mesa is served with water by 
canals which divert it from Uncompahgre River at a place far up the 
valley. Delta is the county seat of Delta County 
Delta. and was so named because it stands on the delta 
paid asec ige formed where Uncompahgre River enters Gunnison 
Denver Sti wiles. River. The south slope of Grand Mesa, the table- 
land to the north, is one of the most noted fruit- 
growing regions of western Colorado. The orchards on this south- 
ward-facing slope are protected from frost in much the same manner 
as those at Palisade, so that fine crops of apples, peaches, and other 
fruit are produced here almost every year. The towns of Hotchkiss, 
Paonia, Cedaredge, and Austin are particularly noted for their excel- 
lent fruit, which is carried to Delta on a standard-gage branch road 
and thence shipped to other markets. Considerable coal is mined at 
Somerset, the terminus of this branch, and finds a ready market in 
the Uncompahgre Valley. 
From Cimarron to Delta the railroad runs entirely on the Mancos 
shale, to which are due the breadth of the valley and the smoothness 
of its sides. At Delta the shale lies in a great structural trough—a 
syncline, as it is called by geologists—whose eastern edge rests on the 
flank of Vernal Mesa and whose western edge rests on the Un- 
compahgre Plateau. Below Delta the railroad changes its course 
from west of north to almost due west, and it therefore soon reaches 
the edge of this shale valley and enters a canyon cut in the underlying 
sandstone. 
A short distance from the station at Delta the railroad crosses Un- 
compahgre River and then runs along the bank of Gunnison River, 
which the traveler has not seen since he left Black Canyon. Here 
the Grand Mesa is in full view to the north (right). All the lower 
slopes of this mesa are composed of the Mancos shale, which is so 
soft that it generally forms valleys wherever it is exposed, but the 
shale in the mesa is protected by overlying sandstone that is capped 
by a thick sheet of solidified lava (basalt). When this lava was 
poured out the present lowlands had not been cut, and the whole 
surface stood at the same level as that of the top of Grand Mesa. 
The volcano or volcanic vent from which this great flow was ejected 
has not been definitely located, but it may have been at a considerable 
distance, for this sheet is probably a part of the great lava flow that 
covered much of this general region, a flow whose remnants can still 
be seen on Grand Mesa and Battlement Mesa, to the north, on the 
Flattops, north of Glenwood Springs, and on other high mesas. If 
these remnants are not a part of a single flow they are probably parts 
of independent flows that occurred at about the same time. As the 
West Elk Mountains, east of Somerset, were a center of great volcanic 
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