June, 1903. A List of Mammals — Elliot. 201 



ranges of hills and low mountains, the highest elevations being some- 

 what above 4,000 feet. The formation is chiefly porphyry and sand- 

 stone, but the rocks are usually well hidden by the soil and heavy chap- 

 arral. This last is made up largely of Chamiso surnae, scrub-oak, manza- 

 nita, buckeye, Ceanothus, etc., which grow very luxuriantly, being almost 

 impenetrable on the northern hillsides and in canons. On the higher 

 hills a small cypress, and a scrub-pine form thickets. Along the 

 canons and creeks live-oaks, sycamores, cottonwoods, and willows form 

 scattered groves." Mr. Heller left Ensenada on the 28th of February 

 and proceeded south, near the coast, making his first stop of only a few 

 days duration at San Tomas, about twenty-five miles from Ensenada, 

 where he procured a few additional donkeys, as his impedimenta was 

 too heavy for rapid traveling with the number of animals secured at 

 Ensenada. From San Tomas he entered the Salado River Canon, in the 

 San Pedro Martir Mountains, and made his first camp about twenty 

 miles west of Trinidad. Of this canon Mr. Heller says : " It is rather 

 narrow, walled in by mountains, which rise one or two thousand feet 

 above the floor, and the canon is a white, sandy dry waste, and more or 

 less of a desert in character. Several shrubs, like Acacia and Larea, are 

 found, together with many desert cacti. The forms which live here have 

 doubtless found their way in over the San Matias Pass through the 

 Trinidad Valley. The altitude of the camp was perhaps 2,000 feet." 

 The next stop was at a small canon called Las Eucinas, which is about 

 1,000 feet above the Salado Canon. The vegetation is somewhat differ- 

 ent, the chief tree being the live-oak, Quercus agrifolia, and the com- 

 monest bush the chamiso." The next camp was "on the western edge 

 of the Trinidad Valley, which is about 500 feet lower than Las Eucinas, 

 and is drained by the Salado River. This side of the valley is in the 

 Juniperus californicus belt, which extends westward from here nearly to 

 Las Eucinas. The valley is elliptical, about 15 miles long by 10 in 

 width. On the east and north it is bordered by high hills, but is open 

 to the desert by a wide pass on the southeast, and on the west rises grad- 

 ually into a broad mesa. In the eastern part of the valley desert plants 

 predominate, such as tree yuccas, creosote, mesquite, cholla and visuaga 

 cacti and many smaller species." One night was passed at a small 

 spring called Aguajito, "on the northern edge of the valley, about four 

 miles northeast. This spring is in the desert vegetation, which is rather 

 luxuriant, and the soil is chiefly white sand." From this camp the train 

 passed on to San Matias spring, the highest elevation reached on this 

 journey. " The spring is situated on the edge of the pass, its altitude 

 being 3,500 to 4,000 feet, on the lower edge of the pinon zone, in a 

 scattered growth of Pinns parryana, and the water drains into the desert. 



