K. PUMPELLY — MEMORIAL OP T. STERRY HUNT. 381 



instance of self-developed genius, for lie had a brief and imperfect public- 

 school education and less than two years in Yale, where most of his time 

 must have been spent in work as an assistant. 



It is as an honored member of our Society and as a geologist that we 

 have to speak of him on this occasion, and it is therefore fitting that wc 

 dwell particularly on those of his contributions to geology which mark 

 his position in the history of the science and which also explain his in- 

 dividual attitude toward some of its more important problems. 



His work in mineral chemistry and in the analyses of rocks led him 

 naturally to the lithological side of geology. The logical and speculative 

 nature of his mind impelled him to attempt the discovery of a general 

 law underlying the origin of the crystalline rocks, both massive and 

 schistose. He began in 1858 with the conception of a solid incandescent 

 globe, which, at least in the outer layer, was an undifferentiated quartz- 

 less basic silicate, approximating dolorite in composition. At this start- 

 ing point, while this mass contained all the non-volatile elements, the 

 atmosphere still contained all the volatile elements, being densely charged 

 with all the carbon, sulphur and chlorine, combined with oxygen or 

 hydrogen, and containing watery vapor, nitrogen and a probable excess 

 of oxygen. He considered that in the condensation of this atmosphere 

 and the reaction of its powerful solvents upon the undifferentiated basic 

 rock lay the key to the genesis of the crystalline rocks. The sulphur 

 and chlorine of the condensing atmosphere combined with the protoxide 

 bases of the rock and went to form the sulphates and chlorides of the 

 ocean and to neutralize its waters. In the waters permeating the rock 

 heated from below an active circulation was established, thus bringing 

 to the surface the matters to be deposited. 



Through this upward lixiviation the primary undifferentiated rock 

 was separated into an upper acidic layer, chiefly of acid silicates, as 

 feldspars with quartz, and a lower residuary basic and insoluble mass 

 charged with iron and magnesium, the two representing the overlying 

 granitic and the underlying basaltic layers required by many geologists. 

 To this explanation he gave the name of Crenitic Hypothesis In the 

 shrinkage of the great thickness, made porous by the lixiviation, he 

 found the cause of the corrugation of the crystalline rocks and of the 

 accompanying early extravasation of basic rocks. The lixiviation or 

 crenitic portion of this hypothesis was not announced till 1884. In its 

 earlier stages its author conceived the primal undifferentiated rock of 

 the early globe to be everywhere deeply buried under its ruins — under 

 a great thickness of fine and coarse sediments produced by the first tie- 

 composition of the rock by acid waters and by extensive subaerial decay, 

 permeated by infiltrating waters and heated from below. Through the 



