1 877.] Prof. Hayden's Explorations. 247 
as but one divide of importance occurred within the district, 
the work was somewhat simplified. This was formed hy the 
Book Cliffs, between the drainages of the Grand on the 
south and the White on the north. Both these rivers flow 
a little south of west, into Green River, which they join in 
Utah. From the junction of the Grand and Green down- 
ward the river is called the Great Colorado. Orograpically, 
the region surveyed is comparatively simple. The Book 
Cliffs are the summit of a plateau about 8oco feet above sea- 
level, continuing unbroken over to the Green River. Toward 
the south these cliffs fall off very steeply, forming deep 
canons that contain tributaries of the Grand River. On the 
north side, with the dip of the strata, the slope is more 
gentle, although, in consequence of erosion, numerous pre- 
cipitous cliffs are found. Descending in that direction, the 
character of the country changes. Instead of an unbroken 
slope, we find that the plateau has been cut parallel by the 
White River drainage, and the long characteristic mesas of 
that region testify to the aCtion of erosion. Approaching 
the river, constantly descending with the slight dip of the 
strata, the bluffs become lower and lower. Though the 
creek-valleys are wide, and at certain seasons no doubt well 
watered, the vegetation is that of an arid country. Dwarf 
pines, pinons, and sagebrush abound, to the almost entire 
exclusion of other trees or grass. Travelling down White 
River, this character is again found to change. A new series 
of bluffs, occasioned by heavy superincumbent strata, gives 
rise to the formation of deep canons. For 45 miles the party 
followed the canon of the White ; that, no doubt, is analo- 
gous to that of the Green, and probably closely resembles 
that of the Colorado in its detail features. Vertical walls 
enclose the narrow river-bottoms, and the slopes of the higher 
portions are ornamented by thousands of curiously eroded 
rocks. “ Monuments ” of all kinds, and figures that can 
readily be compared to those of animated beings, enliven the 
scenery, which otherwise would be very monotonous ; 
2000 to 3000 feet may be stated as the height of the walls 
enclosing the White River. 
Geologically speaking, the district was one of singular 
uniformity. Travelling westward, the older formations, 
reaching back as far as the triassic, were found. This was 
followed by cretaceous, which in turn was covered by ter- 
tiary. About three-quarters of the region surveyed was 
found to contain beds belonging to this period. Owing to 
the lithological character of the strata water was a rare 
luxury in this region, and men and animals were frequently 
