Vol.1] Hall. — Botanical Survey of San Jacinto Mountain. 19 



was offered wheu, during the earthquake of December, 1900, 

 a slope covered by chaparral and extending over some 600 acres 

 suddenly sank for a depth of six to twelve feet leaving along 

 its edges nearly vertical walls, thus exposing the roots of several 

 species of shrubs while still in position. Here it was found that 

 the roots of the Manzanita and Chamisal penetrated to a depth 

 of from four to six feet, — a distance rendered necessary by the 

 small amount of water itresent in the surface soil of these regions. 

 Perhaps the most remarkable case of root development for the 

 purpose of storing moisture is that of Echinocijstis macrocarpa, 

 or "Big-root", the roots of which are sometimes as large as a 

 man's body and completely gorged with water. 



The cha])arral of the higher altitudes occurs only in isolated 

 patches. Wherever the slope becomes too steep or the moisture 

 too scant to support a forest formation, we find the chaparral 

 coming in to take its place. By far the most common species in 

 these ])atches is the Shrn1)by Chinquapin, which covers quite 

 consideral>le areas between the 8000 and 10,000-foot contours. 

 Other species more or less common are Ceanothus cordnlatus, 

 Cercocarpt(.s ledifoUus and Arctostaphijlo.^ patula. 



THE FORESTS. 



While San Jacinto is surrounded on all sides by arid plains 

 and its lower slopes clothed with chaparral the higher portions 

 of the mountain are covered with extensive, somewhat open, 

 forests of pine, fir and cedar. Some idea of the extent of these 

 forests may be had by referring to the map of life zones 

 (plate ii), where the area represented by the red and blue 

 coloring is more or less densely forested, except where 

 meadows occur. This area comprises about 75,000 acres, 

 70,000 acres being occupied by coniferous forest and the re- 

 mainder chiefly by meadows within the forest belt. In general 

 it may be said that the Transition Zone, colored blue on the 

 may), is forested chiefly with Yellow and Sugar Pine and White 

 Fir ; the principal trees of the boreal region being the Murray and 

 Limber Pines. 



The various species of conifers comprising the forests are 

 here taken up in the order of their occurrence on the mountain. 



