Climatic Changes Indicated by Glaciers.—Russell, 325 
with vegetation, the melting of the ice beneath is greatly retarded, 
and in some observed instances the glaciers thus protected termi- 
nate in bold scarps. 
- When a glacier retreats more rapidly than soil can form on the 
abandoned area, so as to admit of the growth of plants, a deso- 
late tract is left about its end, on which concentric lines of stones 
and boulders may indicate halts in the retreat. Barren areas of 
this nature, when the lack of vegetation is not due to the action 
of water from the ice, are good evidence of recent glacial reces- 
sion. When glaciers which flow through a valley having steep 
sides, become stagnant, a general lowering of the surface, de- 
creasing up stream, takes place, which leaves the bordering slopes 
bare of vegetation. The action of rain and rills on such surfaces 
may indicate to some extent the length of time they have been 
exposed. The presence of fine glacial debris on slopes from 
which it would be easily washed by rain, may also furnish evi- 
dence in the same connection. Retreating glaciers sometime 
leave detached masses of ice which are melted in the course of a 
few years and hence indicate rapid changes. |The amount of sub- 
aerial erosion on glaciated areas may also serve to indicate the 
length of time they have been exposed. 
These various classes of evidence usually enable one to deter- 
mine definitely whether a glacier has recently advanced or re- 
treated, and may sometimes afford a clue to the rate of these 
changes. In the study of the glaciers of America we have at 
present no definite quantitative measurements, and must rely on 
such phenomena as have been indicated. 
California: Some of the small glaciers in the High Sierra 
were visited by me in 1883 and 1884. I found that they were 
certainly not advancing, and from the occurrence of barren area 
about their extremities judged that they were slowly receding, but 
could not obtain evidence as to the rate of the recession, 
Observations by J. 8. Diller, of the U. 8. Geological Survey, 
on Mt. Shasta, indicate that the glaciers in northern California, 
like those farther south, are retreating. Evidence of this is 
furnished by barren areas about the ends of several of the glaciers 
and by a conspicuous lateral moraine on the side of the Whitney 
glacier, which in 1887 was about twenty-five feet above the level 
of the adjacent ice. 
Oregon and Washington: The glaciérs on the Cascade mount- 
