June, 1903. A List of Mammals — Elliot. 205 



the extreme north end, where we descended in October. The highest 

 peaks were ascended and both the gulf and coast slopes examined. A 

 good series of deer were obtained and series of all the small mammals 

 taken, but carnivores were rare everywhere, although especial attention 

 was given them." From his last camp at El Alamo Mr. Heller passed 

 northward to the Hanson Laguna range, which is separated from the 

 San Pedro Martir by a gap of considerable extent. A visit to these 

 mountains was desirable in order to determine the northern ranges of the 

 species found to the south. The Hanson Laguna is the southern limit 

 of many forms found in southern California. Mr. Heller's description 

 of this range is as follows : " The range extends north and south without 

 any appreciable culmination into peaks anywhere. Its broad, even charac- 

 ter ceases at 31 ° 35' north latitude, and the range is continued south of 

 this point by a series of broken peaks, which rise somewhat higher than 

 the northern unbroken portion, but lack the pine forest. To the north 

 of the Hanson Lagoon, which is situated on the summit at about 5,000 

 feet elevation, among open groves of yellow pine, the range continues its 

 unbroken character as far as the eye could discern, but falls away consid- 

 erably before reaching the line, the summit near Campo, San Diego 

 County, Cal., being not much over 3,000 feet, and lacking pine forests for 

 almost a score of miles north and south. To the southwest the range 

 merges almost imperceptibly into the Santa Catarina, or Alamo, plain, 

 and slightly more abruptly to the east and north into the Real del Cas- 

 tillo Valley. The entire eastern slope is an abrupt descent to the Colo- 

 rado Desert. This slope is everywhere of a bold rugged granite forma- 

 tion. The crest of the range is considerably nearer the gulf coast or 

 Colorado River than the Pacific, but the drainage is chiefly toward the 

 west. The summit is entirely of a granite formation, and a considerable 

 part of it is covered by huge boulders of decomposition similar to the 

 San Pedro Martir range. 



"The mountains are covered from 4,000 ft. to the summit by a con- 

 tinuous forest growth of yellow pine, Pinus jeffreyi. Scattered among 

 these groves are a few big cone pine, P. coulteri, and incense cedar, 

 Tibocedrus decurrens. Below the pines on both slopes a scattered growth 

 of pihon pines, P.quadrifolia, occur, and on the desert slope below 4,500 

 ft. another pinon, P. monophylla, forms a heavy growth. The oaks, 

 Quercus chrysolepis, Q. wislizeni, and Q. californicus, form a considerable 

 part of the forest at all altitudes above 4,000 ft. The chaparral consists 

 of scrub-oaks, several species of Ceanothus, chamiso, manzanita, Phamnus, 

 etc., and predominates below 4,000 ft. 



" The transition zone as bounded by the yellow pine extends from 

 4,000 ft. on the west slope over the range to 4,500 ft. on the east slope. 



