6 University of California Publications. [botany 



GENERAL FEATURES OF SAN JACINTO MOUNTAIN. 



Position. 



San Jacinto Mountain lies in latitude 33° 48^ north, and in 

 longitude 116° 41^ west, and, as has already been stated, is the 

 southernmost of a number of high peaks in a series of ranges 

 extending across Southern California. These ranges have been 

 considered by some to be the southern continuation of the Sierra 

 Nevadas, while others speak of them as a part of the Coast 

 Ranges, but that they belong to neither of these becomes evident 

 when it is remembered that they were formed in much later geo- 

 logical times and that they are separated both from the Sierras 

 and the coast mountains by Soledad Pass, the highest point 

 of which has an altitude of only 2678 feet. The most impor- 

 tant of these southern mountains is the San Bernardino Range, 

 which lies in a general east-and-west direction in the southwest- 

 ern part of San Bernardino County and culminates in Grajback 

 Mountain at 11,600 feet altitude. 



To the south of Grayback, and just over the line in Riverside 

 County, San Jacinto rises abruptly to an altitude of 10,805 feet 

 and then extends towards the southeast in a series of peaks and 

 broken ridges. San Gorgonio Pass, which lies between these 

 two peaks, is of much interest on account of its being a possible 

 barrier to the migi-ation of species of plants from one mountain 

 to the other. The distance between the two summits, each of 

 which supports an alpine flora, is twenty miles in an ah- line, 

 but in crossing from one to the other it is necessary to descend 

 to an altitude of 2600 feet, where only Sonoran species are found. 



From the east base of San Jacinto the Colorado Desert, 

 crossed by many low ranges, extends to the eastern borders of 

 the state, a distance of something like 120 miles. To the south 

 and southeast, the country is broken up by numerous small 

 ranges and peaks, the highest of which, with the exception of 

 Santa Rosa and Toro Mountains which are a part of the San 

 Jacinto Range, are the Palomar and Cuyamaca Mountains, each 

 with an approximate altitude of 6000 feet; while to the west are 

 found open plains and low mountains extending to a distance of 

 sixty miles where they border on the Pacific Ocean. 



