1903.] NATURAL SCIENCES OF PHILADELPHIA. 5 



places. The following trees identified will give a better idea of the con- 

 ditions among which the birds were found : 



Trees of the Transition Zone. 



Pseudotsuga tnua'onata. Douglas Spruce. 



This is the most conspicuous tree of the region. On Horse creek it 

 is found from the Klamath up to an altitude of 5,500 to 6,000 feet. 



Libocednis deciirrens. Incense Cedar. 



This was also a very common tree from the Ivlamath up to about 

 5,000 feet. 



Pinus lamhertiana. Sugar Pine. 



This is the largest tree of the region, and is common along the sum- 

 mits of White Cloud and Johnny O'Neil ridges from the Klamath up. 

 It is most abundant and of greatest size in the basin of Salt creek 

 about a mile from Grater's. Not observed above 4,500 feet. 



Pinus ponderosa. Yellow Pine. 



Seen from the Klamath up to about 4,000 feet; frequently of large 

 size. 



Pinus attenuata. Scrub Pine. 



This tree grows commonly in the upper part of Seiad Valley, and was 

 noticed along Seiad creek up to 4,000 feet. 



Quercus calif ornicus. Black Oak. 



Though there are several species of oaks in the region, the only one 

 that is very conspicuous is the California black oak. It is found from 

 the KJamath to an elevation of about 4,000 feet. In several places it 

 forms groves of considerable size to the exclusion of coniferous trees. 



Arbutus menziesi. Madrone. 



Seen frequently among the oaks up to their limit, 



Alnus sp.? 



A species of alder grows along all the streams. 



Acer macrophyllum. Big Leaf Maple. 



Observed along streams, but limits not noted. ' ' 



Trees of the Canadian Zone. 



Abies magnifica shastensis. Shasta Fir. 



This tree mixes with the following in the upper edge of Transition, 

 and extends throughout the Canadian zone. 



