GEOLOGY AND NATURAL HISTORY OF LOWER CALIFORNIA. 993 



Aside from the "tiile," a flag which, from the shape of its leaf and 

 the characteristic cylindrical spikelike form of its blossom and fruit, was 

 assumed to be the common "cat tail" {Typha latifolia) of the Eastern 

 States, and clusters of rushes, shown in the foreground of Plate 5, in 

 the bottom of the arroyo, there were on the slopes above numerous 

 cacti, one or more species of Spanish bayonet, the Fouquiera splendens^ 

 and numerous agaves. The most striking of the floral forms, and one 

 which was seen here and only here, was the peculiar dwarf-like Veatchia 

 cedrocensis, or elephant wood (Plate 9). These were rarely more than 

 10 feet in height, though sometimes a foot or more in diameter at the 

 butt, and widely branching. Some of the smaller forms, but a foot or 

 so in height, enlarged abruptly into bulb-like forms, 3 or 4 inches in 

 diameter, on the immediate surface of the ground. The leaves and 

 yellow blossoms are small and inconspicuous, and scarcely show at all 

 in the rather j)Oor photograph from which the accompanying engraving 

 was made. 



The water from the springs above mentioned flows into depressions 

 in the rocky basin, forming pools, in which were found numerous water 

 beetles and one hemiptera, similar, so far as the writer could judge, to 

 the backswimming water boatman {Xotoneeta) of the Eastern ponds. 

 The water itself is sufficiently charged with carbonate of lime to deposit 

 a sinter on the surface over which it flows. During an earlier history 

 these springs, issuing from near-by vents, have built up large dome- 

 shaped masses of sinter, as shown in the left middle back group of 

 Plate 5. Before the arroyo was cut to its present depth, springs were 

 evidently more numerous, and tufa or travertine deposits of considera- 

 ble extent are found upon the adjoining slopes. A large portion of this 

 material is of a dull brownish gray color, slightly compacted, cellular, 

 and of only geological interest. Occasional patches occur, however, of 

 the same material of a white color, or beautifully tinted and veined 

 with green and rose, and so compact as to acquire, in the hands of a 

 workman, a surface and polish like glass. It is, in short, the onyx 

 marble of commerce.^ 



Monday, July 27, the work of inspecting the onyx quarries in the 

 desert to the southeast having been completed, a start was made once 

 more for Eosario, though over for the most part a somewhat different 

 route. After leaving the canyon, or arroyo, .and the rocky divide, our 

 route lay over an undulating desert plain with flat-topped mesas on the 

 southeast and mountain peaks visible on all sides. A portion of the 

 plain was actually paved with basaltic fragments, though no basalt 

 flow in place was observed. The onyx beds, noted above, lie in some 

 cases like a pavement on the floor of the desert, the chief flora and 

 general character of the landscape being as shown in Plate 10. At the 

 end of the second day from the arroj^o, i. e., Tuesday night, July 28, we 



'See the Onyx Marbles, their History, Origin, and Uses. Report U. S. National 

 Museum. 1895, pp. 539-585. 

 NAT MUS 95 63 



