The author sets out to introduce some order into the terminology of the study of frost action and permanently frozen ground. “Cryopedology” is his name for these studies. There is clearly a need for some rationalization, but the new words he introduces, derived largely from Greek and Latin roots, are in many cases rather cumbersome for every-day use. The ideas and phenomena associated with the new terms are very clearly conveyed and the paper renders a useful Service in sorting out the various meanings given to the older words and phrases in the past.

Nevertheless it seems a pity to replace such a self-explanatory word as frost-heaving by the term “congeliturbation,” although as the author points out there is no way of deriving from such verbal expressions corresponding nouns for the products of their action. Instead of frost-heaved silt the proposal is presumably “congeliturbate silt.” Where the action of frost is merely to freeze the water in the rock voids and fissures without building up ice lenses, the Splitting open of the rock due to the water-ice expansion is called “congelifraction.” A few lines after introducing this word it appears that the author falls into his own trap by using the more familiar term “frost action.”

The terminology of the movement of soil downhill as a result of frost-heaving and thawing on slopes is discussed at some length. In considering the terms that have been used in the past to describe the material moved by the above process it is surprising to find the word “warp.” According to the Shorter Oxford English Dictionary this word as a noun dates from before 1700 and is an alluvial deposit laid down naturally or artificially by water and even to-day it is in common use amongst drainage engineers. The term “solifluction” introduced by Andersson (1906) is frequently used for the migration of weathered material downhill under the action of frost-heaving and thawing. Although Andersson himself may not have understood the mechanics of the process, his type localities are all in cold regions where the phenomenon is important. Bryan wishes to use the word “congeliturbation” in this sense, but there does not seem to be sufficient differentiation in his use of the word. Presumably, for example, an area of level ground subjected to annual frost-heaving and thawing would be called “congeliturbate ground,” but in no sense will it be migrating downhill.

The widespread lowering of relief produced by “congeliturbation,” which various authors have suggested as the origin of the smooth broad upland surfaces in Tibet, Iceland, and South East Alaska, is appropriately called “cryoplanation.”

The active Zone above permanently frozen ground, which seasonally freezes and thaws, is termed the “supragelisol”; the word “mollisol” appears to be synonymous. The combined actions of thawing and softening of the mollisol are known as “mollition,” but it is often necessary to refer to these two actions individually. Several other words are introduced for the various zones in permanently frozen ground, but to use the author’s summarizing phrase, they are “somewhat overpowering in number.”

While it is always' to be welcomed that scientific terminology should be set on a logical and systematic basis, the reviewer feels that many of the terms are too complicated in design and that this, coupled with the large number presented all at once, makes them a trifle overwhelming. The descriptive phrase and “adjectival” noun nomenclature in current use in the study of frozen ground are also readily understood by the layman; “surface zone of annual freeze and thaw” and “ground ice” are examples. The writer suggests that the rationalization of these and similar terms might be a better solution of this difficult problem.