GEOLOGY — CHAMBERLIN. 173 



must also meet the test of its working applicability to the compli- 

 cated geological phenomena to which it is supposed to be antecedent, 

 and the prime motive in this cosmological inquiry, so far as I am 

 individually concerned, has lain in the imperative need for a more 

 satisfactory working basis in geological dynamics, since the cosmo- 

 logical hypotheses previously entertained seemed to encounter serious, 

 if not fatal, difficulties at many points of geological as well as astro- 

 nomical application. In the endeavor to develop the applications of 

 the new working hypothesis at as many vital points as possible my 

 work has been quite distributive and is not easily reviewed in a brief 

 report. Selected points may therefore best indicate the nature of 

 the work and the character of the results, and of these I choose two. 



I. Deformations of the Earth. 



From the geological point of view the most radical departure of the 

 planetesimal hypothesis from the gaseous and meteoritic hypotheses 

 lies in the primitive structure of the earth. An origin from a gaseous 

 nebula carries the corollary that the earth was originally a molten 

 globe. The same appears to be true of the meteoritic hypothesis 

 when the latter is assumed to have a quasi-gaseous constitution and 

 to be aggregated directly by gravitation. Varieties of the meteoritic 

 hypothesis may perhaps be postulated which would give rise to an 

 earth built up by gradual accretion, essentially as under the planet- 

 esimal hypothesis, but after protracted effort I have been unable to 

 give to such a postulate a plausible origin and a consistent working 

 method. An earth built up by the gradual accretion of planetesimals 

 may never have passed through the molten state, and hence its mate- 

 rial may have preserved that distinctive heterogeneity which arose 

 from the ingathering of the various kinds of material by individual 

 accessions. The vulcanism of such a body must have pursued quite 

 distinctive lines, as set forth in my last report (Year Book No. 3, 

 pp. 238-244). The study of these methods has been carried to fur- 

 ther details, but their general tenor is sufficiently indicated in the 

 last report to serve the purpose of the present sketch. 



The deformations in a body thus constituted must apparently 

 depart even more radically from those of a body whose material has 

 passed through the liquid state and has thus been subjected to such 

 systematic arrangement of the material and distribution of the tem- 

 perature as the liquid state must have permitted. The temperature 

 of a body built up by the slow accession of material from without, 

 whose heat of impact may have been largely lost by radiation from 

 the surface in the course of the ingathering, must be assigned largely 

 to compression under its growing gravity and to such molecular, 



