aEOLOGY AND NATURAL HISTORY OF LOWER CALIFORNIA. 991 



day we passed over the landscape shown in Plate 8 and crossed a low 

 divide, where the "lost mountain" type of structure, already described, 

 became first evident. The ground was covered with angular and 

 sharply-rounded pebbles of acid and basic eruptive rocks, interspersed 

 with thin crusts of lime carbonate, indicative of lake-bed deposits. A 

 small outcrop of hard, compact, reddish quartzite was passed a few 

 miles before San Juan de Dios, which place we reached about 3 p. m. 

 on the 23d. 



A little stream makes up out of the rocks in a canyon, flows a short 

 distance, and sinks in the sand. Yet 'tis enough for human needs, and 

 here in his adobe hut, thatched with palm leaves, lives a Mexican rais- 

 ing cattle and children (Plate 4). We are given a hearty welcome, and 

 fed bountifully on stewed quail, beans, skim milk cheese, wild honey, 

 and the leathery tortilla, made from corn crushed on the aboriginal 

 metati. 



The landscape here, except in the creek bottoms, retains its general 

 desert aspects. The flora is composed of various species of cactus, 

 among which the log-like cereus already mentioned is conspicuous. 

 The Fouquiera and agave also abound. The large tree shown is a Cot- 

 tonwood, which I learned was not indigenous, but brought when a mere 

 slip from San Diego, California. 



The hill shown is composed at its base of compact brecciated quartz 

 porphyry and diorite, capped by a light porous liparite. Small out- 

 crops of black basalt occur well uj) the slopes, which are covered by 

 bowlders rounded and waterworn of liparite and andesite. 



The following morning (July 24) a general round-up was held, and 

 new animals obtained as far as possible, those obtained at Eosario 

 being already footsore. As the distance to the next water was estimated 

 at from 35 to 40 miles — a distance far too great for one day, over rough 

 trails and with unshod animals — it was decided to delay our start until 

 about noon, making a dry camp at night and finishing the trip the day 

 following. This was the programme finally carried out. 



The first few miles of the route lay upward through narrow canyons 

 with steep, precipitous walls and loose, rocky bottoms, the slopes being 

 covered with bowlders of liparite, and the country rock consisting of a 

 loosely consolidated and irregularly bedded coarse gravel and bowlder 

 aggregate cemented by fine sand. Finally, emerging from the canyon, 

 or arroyo, we found ourselves on a high, level, liparite-topped plateau, 

 which extends for miles in a northerly and westerly direction. The 

 Agave shaicii, with central stalk 10 to 15 feet in height, stand here by 

 the tens of thousands in full bloom in the midst of piles of rocks so hot 

 and forbidding that in spite of myself I drive by with scarcely a look. 

 These continue abundant well over toward the east coast and are often 

 beautifully symmetrical. For years these plants gather from the stingy 

 soil the necessary nutriment for the flower stalk, storing it up in their 

 thick, fleshy, bayonet-like leaves. When the season finally arrives, 



