312 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1952 



in 1949, Dr. Parker found that instead of the sharp, high glacial face, 

 as in 1918-31, the face had receded by melting and that there was a 

 gentle upward slope to the snow-covered ice farther back against the 

 mountain. The condition that occurred in 1951 is shown in photo- 

 graphs made by Dr. Irving Friedman (pi. 4) . 



At present the main area of the glacier appears newer than a dome- 

 shaped mass of ice which is the best source of preserved specimens. 

 This dome, well shown in the photographs, and sometimes known as 

 the "old glacier," is what remains of the imposing ice cliff photo- 

 graphed by Dr. W. C. Alden in 1922 (pi. 2). F. C. Curtiss, of the 

 Custer National Forest Headquarters in Billings, Mont., attributes 

 the large amount of new ice covering the "old glacier" to the wet cycle 

 which has occurred there since the dry years of the 1930's. With the 

 recession of the "old glacier" the pool resulting from the melting ice 

 has become enlarged, and the face of the ice cliff is very dark with in- 

 cluded morainic debris and with that which falls down from the 

 covering of the dome above. 



Two principal types of glaciers, from the point of view of age, oc- 

 cur in the United States. The first category, much in the minority, 

 consists of those which can with "reasonable certainty be said to have 

 persisted from the Pleistocene ice age." They originate at higher 

 altitudes or for other reasons appear much more permanent. The re- 

 mainder, averaging smaller and located at lower altitudes for the 

 most part, and including most of the glaciers of the United States, are 

 thought to have existed only during the "little ice age" period. Thus, 

 the age of Grasshopper Glacier is very uncertain, depending on the 

 category to which it belongs. Although most of the North American 

 glaciers of the "ancient" type occur in the Far West and Alaska it was 

 believed by Matthes that several of that sort occur in Glacier Na- 

 tional Park, Mont., and in the Wind Eiver Eange of Wyoming. 

 More recent studies of the factors leading to the development of 

 glaciers have suggested that all the Glacier National Park and Wind 

 Eiver Eange glaciers instead belong to the "recent" category, thus 

 originating within 4,000 years. The Beartooth Eange glaciers have 

 not been studied in detail from the standpoint of age, but they are 

 comparable to most of the Wind Eiver Eange glaciers, with respect 

 to altitude and their location in old glacial cirques on the east side of 

 the divide where snow from westerly winds blows onto and augments 

 the ice. The eventual placement of Grasshopper Glacier, regarding 

 the category to which it belongs, may have a direct bearing on the age 

 of the oldest insects there included. 



THE SPECIES OF GRASSHOPPERS PRESERVED 



Nearly 40 years ago preserved grasshoppers had been collected for 

 scientific purposes from the ice of Grasshopper Glacier, but their oc- 



