WESTERN BASE OF PROMONTORY RANGE. 103 



tirely disappeared, and the water, althougli apparently shallow, 

 came nearly up to the base of the hills. Near the margin of the 

 lake it is not safe in all places for animals to pass, as the almost 

 constant exudations of salt water from the edge of the grass, un- 

 dermine the surface, rendering the narrow intervening beach 

 treacherous and miry. The water to the westward appears bold 

 and deep ; and enough has been seen to convince me that a large 

 sail-boat will be absolutely indispensable in the contemplated sur- 

 vey, for the supply of the different parties with provisions and 

 water. Wood there is none. Fuel for cooking, can, however, be 

 generally obtained from the artemisia which abounds almost every- 

 where ; but timber for the construction of the triangulation sta- 

 tions, will, in most instances, have to be transported by water, or 

 hauled down from the canons of the mountains. 



The rocks observed were porphyry, gneiss, dark slaty shales, and 

 metamorphic sandstone, dipping to the north-east. After proceed- 

 ing some miles to the north, dark limestones with white marble 

 veins occurred, alternating with clayey shales. The rocks on this 

 side of the promontory are much more rugged than on the other, 

 or eastern slope, presenting numerous lofty escarpments where 

 they crop out, the dip being to the east. A cactus, with very long 

 prickles, was observed near our morning camp ; and at the spring 

 where we nooned, a small jointed cane trailed on the ground, in 

 some instances to a distance of more than thirty feet. The men 

 made excellent pipe-stems of this material. The spring where we 

 encamped for the night was an oval hole or pit, with perpendicular 

 sides, about fifteen feet long, six broad, and four deep. The water 

 was tolerably good: a small spring, rising at the base of the 

 hill, ran into the lake close by. These springs afterward afforded 

 us nearly all the water used upon the survey of the west shore of 

 the lake ; but a voyage of fifty miles was frequently necessary to 

 obtain a supply even for a few days. 



Wednesday^ October 24. — Clear and calm. Ther, at daylight, 

 19° ; sunrise, 24°. Continuing our journey up the lake-shore, we 

 shortly came to a brackish spring, where there had been a camp of 

 Indians the night before. We had thought last night that we saw 

 their fires, but they had fled, alarmed probably by the report of 

 some guns that had been discharged in our camp. A quantity of 

 some species of seeds they had been beating out lay in small heaps 

 around, and I found an old water-bottle they had left in their haste. 

 It was ingeniously woven of a sort of sedge-grass, coated inside 



