THK MAMMALS OF MOUNT MAZAMA. 
Fort Klamath itself is in the midst of a forest of magnificent 
Yellow Pines, which covers the greater part of an extensive area of 
flat ground between the tule marshes at the north end of Klamath 
Lake and the base of the Cascade Range. The altitude of this flat 
is about 1,280 meters (4,200 ft.), and it is in the upper part of the 
Transition Zone. The pine forest is interrupted by hot pumice 
meadows and cold Boreal swamps. Several gigantic springs of 
exceedingly cold water from the mountains break out of the ground 
and flow away to the lake in large streams (Fort Creek, Wood river 
and others), carrying lines of Boreal species through the Transition 
plane. Thus these streams, and the adjacent cold, swampy flats, 
support small forests of Lodgepole Pines, scattered clumps of Aspens, 
and a number of bushes and flowers belonging to the Canadian Zone 
above. To the same influences should be attributed the infusion of 
Boreal birds in the pines of the Fort Klamath plain, and the presence 
along the cold streams and swamps of such Boreal mammals as the 
small Shrew {Sorex vagrans)^ the large Water Shrews {Atrophyrax 
bendirei and Neosorex navigator)^ the Mountain Jumping Mouse 
(Zapus trinotatus montanus)^ and the Long- tailed Mountain Vole 
(Microtus mordax). 
The road from Fort Klamath to Crater Lake follows the south 
slope of the mountain, and affords a direct and easy grade without 
the complications that usually result from canyon or gorge slopes on 
mountain roads. The soil is mainly pumice sand, very fine and 
very dusty. Anna Creek Canyon, with nearly vertical walls of 
volcanic tuff", lies close to the road on the east side, and carries 
Boreal species down considerably below the altitudes they reach on 
the adjacent slopes. 
CRATER LAKE, OREGON. — Crater Lake is a body of 
clear indigo-blue water, about five miles in average diameter and 
600 meters (2,000 ft.) in greatest depth. It occupies the crater 
of the extinct volcano of Mount Mazama, and is completely 
encircled by a continuous wall of cliffs varying in height from a 
little less than 300 to a little more than 600 meters (1,000- 
2,000 ft.). . There is no break in this wall, which is so nearly 
perpendicular that climbing up or down is impossible, save in 
