30 BULLETIN 54, U. S. DEPARTMENT OF AGRICULTURE. 
THE GOOSE LAKE BASIN. 
South of the Abert Basin, but without any certain structural relation thereto, is” 
another north-south trough in which lies Goose Lake, between the Warner Mountains 
on the east and the Modoc lava plateau on the west. The southern portion of this 
valley is occupied and drained by the Pitt River, the northern, or Goose Lake por- 
tion, being separated therefrom only by an alluvial divide just south of the lake. 
This divide is apparently recent and is now only a few feet above the lake. It is 
probable that the lake has frequently overflowed it, and indeed it is reported that this 
has occasionally happened within the memory of present inhabitants. Undoubtedly 
the freshness of Goose Lake is to be thus explained. 
THE, MADELINE BASIN. 
On the lava plateau north of the Honey Lake Basin is the very similar basin of the 
Madeline Plains. The structure of its walls is very irregular and in many places the 
divides are not exactly determinable. A number of low passes lead both to the Pitt 
River drainage and to the Honey Lake Basin, and some one of these may formerly 
have served asa channel of overflow. However, old strand lines are visible at several 
points about the basin and serve to indicate the existence and fluctuations of an 
inclosed lake.. Until passesand strands have been studied more exactly and compared 
with each other it is impossible to read with any assurance the history of this ancient 
lake or to determine whether it overflowed or how long the overflow continued. 
Still less is it possible to decide whether the overflow, if any, was into the Pitt River 
or into Honey Lake. 
The present floor of the valley is flat and featureless, except for occasional dune 
areas. There are many small local playas, but no area of general concentration is 
noted on the available maps or was observed by the writer. The plain is nowhere 
saline. At its southwestern corner an outlying tongue of the plain has been cut off 
by a low alluvial divide and forms the Grasshopper Valley. This valley was evidently 
once a part of the Madeline water body, but its subsequent relations thereto are uncer- 
tain. Itnowcontainsasmallmarch. The total area of the Madeline Basin, including 
Grasshopper Valley, 1s about 900 square miles. 
‘ THE MODOC LAVA BEDS. 
West and northwest of the Goose Lake Valley a series of great basalt flows stretches 
westward to the volcanic uplift which culminates in Mount Shasta. Diversified only 
by minor faults and folds and by a few deep and narrow canyons of erosion, the region 
has not developed any extensive drainage system and advancing desiccation has 
destroyed what little drainage there once was. The streams are dry and the occa- 
sional shallow depressions are areas of inclosed drainage floored by local playas. The 
region is not unlike that surrounding the Christmas Lake Valley as described on page 
23, and, like it, has no importance to thisinquiry. The small basins of the lava beds 
are so tiny and their inclosed condition is so recent that salt accumulation in them is 
practically out of the question. Thisappliesalso to the basin of Medicine Lake on the 
western edge of the area near Mount Hoffman, though it is not so fully desiccated as 
its analogues to the east. 
THE KLAMATH LAKES. 
On the northeastern border of the lava bed region are a series of shallow basins 
holding the Klamath Lakes. The geologic history of this region has not been studied 
in detail, but a brief examination of the major features has suggested to the writer 
that the present lakes probably occupy local depressions in the bed of a much larger 
lake, perhaps of late Tertiary age, which lake has been drained by the cutting of the 
gorge of the Klamath River. A similar history, on a smaller scale, is to be ascribed 
