CERBAT MOUNTAINS—VOLCANIC ROCKS—STRIPED CAÑON. 49 
was continuous along the valley, and between Camps 113 and 114 was found very thick, con- 
taining large pebbles. The next day, Mr. Marcou found its thickness to be 1,000 feet. The 
presence of this diluvium is again noted at many points along the river down to its junction with 
the Great Colorado. 
Cerbat Mountains.—This range is parallel with the Aquarius mountains, and forms the western 
side of the valley of the Hawilhamook. The rocks are similar to those of the Aquarius 
mountains. Two or three specimens were found in the collection. One of them, No. 14, is a 
beautiful flesh-colored granite, containing dark-colored mica, Another, No. 17, is gneissose, 
and probably metamorphic. A beautiful specimen of fibrous hematite—specular iron—was 
found in this range. It is a variety called bloodstone by jewellers, and a description of it may 
be found in Chapter X, No. 91. Some of the lower ridges of this range of mountains were 
crossed between Camps 115 and 120. Between Camps 115 and 116 these ridges were of granite 
and gneiss, which were traversed by veins of quartz and feldspar. Between Camps 118 and 
119 Mr. Marcou observed granite containing large crystals of white and rose-colored feldspar, 
also quartziferous red porphyry and dykes of quartz and trap, trending north 70 degrees west. 
Near Camp 120 an extensive outcrop of trap-rock was found, which, according to Mr. Marcou, 
formed two great mountains. 
Volcanic rocks, Artillery Peak.—Opposite Camp 117 a perpendicular cliff, capped with a 
layer of basaltic lava, was found. This appeared to have tlowed from the northeast, and 
formed a mesa or table-land, which was also seen between Camps 117 and 118. At Camp 119 
a high cone was found upon the right. This appeared to be volcanic, and was called Artillery 
Peak. An interesting figure of it is given on page 103 of Captain Whipple’s report. Mr. 
Marcou observes that this mountain is pointed, and has blackish sides like volcanic lava. It is 
most probable that the lava proceeded from this point. This mountain, as will be seen by 
reference to the map, rises at the southern end of the Cerbat range, and from this point the 
river turns to the west. There is also opposite to this point a considerable break in the 
Aquarius range, through which the Santa Maria river flows from the northeast. In a direction 
southeast from Camp 121, an extensive valley or plain was seen. This was bounded on the 
east by the prolongation of the Aquarius mountains, and on the west by the continuation of a 
chain parallel with the Cerbat range, but which is intermediate between it and the Colorado 
river. The end of this range was crossed between Camps 122 and 123, and the pass is called 
Striped Cañon. Captain Whipple gives the following description of the rocks which are found 
there: ‘Soon after starting we entered a chasm cut through a dyke of greenstone, with horizon- 
tal veins of granite and white quartz. The vertical section was variegated like jasper. The 
rock in some places rose in vertical planes to the height of 300 feet. Upon the top it was 
broken, presenting, sometimes, a fancied resemblance to Gothic architecture.””* 
Mr. Marcou states that the rocks are metamorphic and somewhat plicated, but the trend is 
preserved. He further observes that the rocks are of quartzite, whitened by veins alternating 
with brown, black, and green mica-schists. (Notes, February 15.) Veins of iron ore were also 
found in the caiion. 
The course of the river in its passage across the Striped Cañon is exceedingly tortuous, but 
after emerging from the cañon turns to the north and follows the valley of the river leading to 
the Great Colorado. The trail which follows this valley thus passes northwesterly at the west- 
ern base of the range just described. In this valley Mr. Marcou observed a great development of 
drift deposites. "Near Camp 124, he notes the occurrence of red pudding-stone and Tertiary 
red sandstones. These strata are raised up, and Mr. Marcou has recorded the presence of 
trappean rocks in the vicinity, to which we may refer their uplifted condition. 
Basaltic lava.—The lower part of the valley of the Hawilhamook is contracted by the presence 
of thick beds of basalt crowning the summits of the mesas. This rock was first observed near 
Report of Captain Whipple, Itinerary, p. 105.- 
Tt 
