336 The American Geologist. May, 1892 
are lacking, these considerations show that the retreat has been 
very gradual, and was undoubtedly accompanied by many minor 
changes of which we have no record. The indications are that 
the retreat of the glaciers has been so gradual that it is doubtful 
if ordinary weather observations would be able to detect the 
change, unless carried over a period of several decades, and 
therefore could not be expected to appear in the weather records 
now available. For example, a decrease in the mean annual rain- 
fall of the Pacific coast to the extent of one-tenth of an inch per 
year would, in the time covered by the retreat of the glaciers, 
produce marked results, but would scarcely be detected in a series 
of observations covering less than a decade, and even then the 
stations would have to be numerous to allow one to draw definite 
conclusions. Similar considerations hold true also in reference to 
an increase of temperature. 
These considerations indicate that the growth of glaciers and 
the initiation and decline of Glacial epochs, are caused: by very 
gradual climatic changes which would only become conspicuous, 
as climatic changes are now studied, after the lapse of centuries. 
Washington, D. C., February 29, 1892. 
EDITORIAL COMMENT. 
Sir ANDREW C. RAmsay, BART. 
With the death of the late director-general of the geological 
survey of Great Britain and Ireland, at his home at Beaumaris (1. of 
Anglesey) on the 9th of December, 1891, at the age of 77, a con- 
spicuous and long familiar figure disappeared from the geological 
world. A born geologist, he needed only the opportunity for 
showing his power and this came during a visit to the Isle of 
Arran (for the benefit of his health, never too strong), through 
accidental contact with Prof. Nichol, of Glasgow. Mapping and 
modelling the island, his work attracted the attention of Murehi- 
son at the meeting of the British Association, at Glasgow, in 1840. 
Through his assistance Ramsay was attached to the survey and 
assigned to South Wales. . In 1845 he was made local director 
for Great Britain, which office he held until on the death of Sir 
