680 Grove Karl Gilbert. 



prediction — but the misprints in this article in the 

 American Meteorological Journal were so numerous that 

 its author had no satisfaction in it — ripple marks, joints, 

 the sufficiency of terrestrial rotation for the deflection of 

 streams, the origin of the "craters" of the moon, which 

 he suggested might be the result of meteoric impacts, an 

 idea that he later applied also to Coon Butte in Arizona 

 in an address on the "Origin of Hypotheses" (1896) ; the 

 systematic asymmetry of mountain crests in the Sierra 

 Nevada as a result of glacial erosion, and the convexity 

 of hill tops as a result of soil creep — a small problem that 

 he had left unsolved nearly forty years earlier in the 

 chapter on Land Sculpture in the Henry Mountains 

 report. He also collaborated in producing an elemen- 

 tary text-book on Physical Geography. 



In all these studies, his keen insight tended, as has been 

 well said, "to bring into declared form the basal prin- 

 ciples that underlie the phenomena in hand." He was 

 thus led to understand earlier than many of his col- 

 leagues that the Adirondacks were not, as had long been 

 thought and taught, a rising but a sinking land mass 

 when the Potsdam sandstones were laid unconformably 

 on their flanks ; and that the fresh-water Tertiaries of the 

 Rocky mountain region had not been deposited in great 

 lake basins, a long prevalent view that he had himself 

 adopted in his early western work, but that they were 

 largely deposited by aggrading streams. It was, there- 

 fore, in view of the breadth as well as the depth of his 

 researches that he was awarded the Wollaston medal by 

 the Geological Society of London in 1897, and the Walker 

 Grand Prize — a thousand dollars — by the Boston Society 

 of Natural History in 1908. 



It remains to recur briefly to Gilbert's return to the 

 Great Basin in 1901, with the object of revising the field 

 of his early work on the origin of the Basin ranges ; for 

 a new discussion of the old problem had been awakened 

 by a junior geologist who expressed strong dissent from 

 the fault-block theory. A season of successful field work 

 supplied the veteran observer with more detailed evi- 

 dence than had been before available for the correctness 

 of his theory — which, it mav be noted, had received inde- 

 pendent confirmation from Russell's work in Nevada and 

 Oregon some years before, and was about to gain still fur- 

 ther support from studies bv Campbell in Death valley 

 and by Louderback on the Humboldt ranges ; but most 



