126 PROCEEDINGS OF WASHINGTON MEETING. 



source of Warm creek, the stream which has been appropriated for the purpose of 

 irrigating the well-known colony of Riverside. Warm creek has no visible connec- 

 tion with any of the streams that descend from the Sierra Madre; it rises in the 

 valley itself, fully three- miles away from the foot of the range. There is no obvious 

 reason for its being there, but the water gathers from little rills and ditches within 

 a space of about a quarter of a mile, acquiring within that distance nearly its full 

 volume of from 2,000 to 2,500 inches during the dry season. At other points, also, 

 "artesian" springs rise with considerable force and volume, and in the immediate 

 floodplain of the Santa Ana river, rivulets gather at many points on the margins, 

 at the foot of the bluff, some 7 or 8 feet above the river channel, and How toward 

 the latter to increase the volume of the stream. It thus happens that "the entire 

 flow of the Santa Ana river" has been appropriated at at least three different 

 points, each appropriator receiving a good flow, and that in the absence of any 

 obvious important additions from incoming streams. As maybe supposed, bore- 

 holes sunk in this region of spontaneous flows encounter at very small depths (from 

 120 to 150 feet) very copious flows of artesian water, in cobble-beds; while near the 

 border of the valley not only is a greater depth required and the outflow less, but 

 the materials penetrated are much flner. 



Since the terraces of reddish loam that border the foot of the Sierra Madre from 

 the head of the valley to the San Gabriel river indicate plainly that the subdivision 

 of the valley into two drainage basins is a comparatively recent event, it does not 

 seem improbable that the artesian reserve referred to might be tapped by deep bor- 

 ings much farther westward than has heretofore been attempted; perhaps within 

 easy reach of the city of Los Angeles. 



A very striking exemplification of the origin of cienegas exists in the valley of 

 Temescal creek, one of the southern affluents of the Santa Ana river, in San Ber- 

 nardino county. This creek is really the natural continuation of the San Jacinto 

 river of San Diego county; but an intervening lake basin (Lake Elsinore) pre- 

 vents actual flow from the latter stream to the Temescal valley, save in seasons of 

 extraordinary rainfall. Its water is supplied almost entirely from the canons of 

 the Santa Ana mountains, which have a rather copious rainfall in their higher por- 

 tions. At the head of the valley there is a small lake | Lee lake), which, with no vis- 

 ible inflow, nevertheless has at its lower end a steady outflow of about 400 miner's 

 inches of water during the dry season, thus forming part of the water-supply of the 

 "South Riverside" colony. Examination shows that the lake is ted entirely by a 

 series of springs, or rather an almost continuous ooze, from the enormous masses of 

 granitic and other debris that have' accumulated in front of the two uppermost 

 canons of the Temescal valley, and which reach entirely across the valley to the 

 foot of the (Temescali range opposite. These debris masses are so porous that actual 

 surface flow very rarely occurs, and no well defined bed for a stream exists save 

 where, close to the lake basin, the materials are relatively line. Evidently the main 

 body of the rainfall gathered into these canons is stored in the coarser portions of 

 the debris-fans above. 



Below this lake basin the Temescal valley is divided lengthwise by a series of low 

 ridges formed of materials mostly impervious to water, of Tertiary age. In from 

 of the canons of this lower portion of the valley similar great debris masses have 

 accumulated also: but since the impervious ridges mentioned prevent the outflow 

 of water save during actual freshets (when small streams pass through gaps in the 

 ridges), extensive cienegas have been formed between the valley ridges and the fool 



