VOL. Iv.] Trees of Southern California. 335 
cafions are usually clothed with them. At about 3000 feet a 
thin strip of dwarf pine (Pinus tuberculata) stretches for some 
miles along the face of the range, bounded above and below by 
the dense chaparral of Ceanothus and manzanita, which at this 
altitude has replaced the Adenostoma of the lower slopes, and 
is otherwise unbroken for another thousand feet. At 4000 feet 
the spruce is displaced by the other coniferous trees which consti- 
tute the main forest. Below 5000 feet this is mostly confined to 
the northern slope of the range, but above that over- 
flows to the southern side, and, indeed, below it on sheltered 
slope-exposures. It is essentially a yellow pine (7. ponderosa) 
belt, that being the prevailing species nearly to the tree limit; 
with it are commingled, without any apparent vertical disposition, 
many firs (Ades concolor) and Post Cedars, smaller numbers 
Black and Big-cone Pines (P. /effrey¢ and P. Coulterz), and still 
ugar Pines, together with an abundance of Kellogg’s 
Oak, especially at the lower levels. This forest continues without 
appreciable difference to about 11,000 feet on the sides of Gray- 
back Mountain, where it begins to be intermixed with Pinus 
contorta, which in small isolated groups occurs in Bear Valley, 
as low as 6000 feet. This in turn gives way at about 11,500 
feet to Pinus albicaulis, which alone, forming the topmost belt, 
reaches nearly to the summit, 11,725 feet above sea level.* On 
the northern side of the range, which, it must be remembered, 
is the one facing the desert and affected by its aridity, the spruce 
Te-appears at about 7000 feet altitude, but very sparingly, and 
in small groups in sheltered and moist situations. At 6000 feet 
Juniperus occidenialis is mingled with the pines, and in one 
place, mixed with Cercocarpus /edifolius, forms a belt between 
6000 and 7000 feet altitude. Beneath this, and separated from 
it by an interval of chaparral, is a similar belt of Pifion Pines 
(P. monophj lia) between 4000 and 5000 feet, and connecting in 
places with the upper edge of the Yucca belt. The Juniper and 
the Pifion belts are about twelve miles long, their failure to 
extend the whole length of the range being due to other causes 
than elevation. 
* For most of my information concerning the Grayback forest I ain 
indebted to Mr. W. G. Wright, who has repeatedly explored that mountain. 
