272 Field Columbian Museum — Zoology, Vol. III. 



tributed along dry washes, in some places forming thickets of large 

 extent. On the rocky hillsides and mesas bordering the more sandy 

 portions of the desert cacti are abundant, chiefly cholla, Opuntia 

 tesselata and 0. echinocarpa, a species of Cereus, and the barrel cactus, 

 Echinocactus. In the canons the fan palm, Neowashingtonia fila- 

 mentosa, forms the most conspicuous part of the vegetation, associated 

 with which are willows, cottonwoods, sycamores, screw-pod mesquite, 

 and low thickets of Acacia. Farther up the canons, at 2,000 feet, 

 occur the juniper, piiion pine, and agave, while a few Yucca moha- 

 vensis occur at the mouths of the canons. Owing to the abruptness 

 of the mountains and the low elevation of the plain upon which they 

 rest, the coast and mountain flora and fauna are brought down into 

 close contact with forms which are characteristic of the lowest part 

 of- the desert." A Citcllus and a Perognathus are described as new 

 from this locality and topotypes of Dipodomys m. simiolus, Perog- 

 nathus p. bangsi, Nyctinomus femorosaccus, and Neotoma bella were 

 obtained. 



From Palm Springs Mr. Heller traversed the Morongo Pass 

 through the San Bernardino Range to its northern side. This Pass 

 which "marks the eastern boundary of the valley, has an elevation 

 of 3,000 feet, and the valley itself is about 500 feet lower, and forms 

 a connection between the Colorado Desert and the southwestern arm 

 of the Mohave Desert. The valley is about ten miles in length, with 

 a width of two or three miles, and has a gravelly floor and rolling 

 surface, due to the washes of the several creeks which cross it at 

 right angles to break through the low hills on the southeast to the 

 Colorado Desert. The valley is in the Lower Sonoran Zone, being 

 covered by a pure growth of creosote in many parts. Yucca niolia- 

 vensis is also an abundant species and here reaches its maximum 

 dimensions. To the south, the Pass is walled in by San Jacinto 

 Mountain, which rises very abruptly from the level floor of the desert 

 to a height of 10,805 feet. The San Bernardino Mountains form the 

 northern wall, the highest peak lying less than fifteen miles to the 

 north and attaining an altitude of 11,485 feet. At Whitewater, the 

 mouth of the Pass is a little more than two miles in width, with a 

 gradual decline eastward to the desert. To the west it keeps its 

 broad, open character and gradual ascent to the summit, 2,600 feet, 

 a few miles west of Banning, where one day was passed and a few 

 specimens procured. Near Whitewater the Pass is filled with white 

 sand washes, and the Whitewater Creek from the San Bernardino 

 Mountains enters the desert from the north at the mouth of the 

 Pass, and the mountain vegetation, and to a slight extent the fauna 



