180 GROVE KARL GILBERT— DAVIS [M " M0IES [^^ 



problem, and to one that was more to his liking; such, for example, as the structure and origin 

 of the basin ranges, which by good rights still belonged to him. When he did take up that fine 

 problem seven years later, an unhappy accident caused him to turn from it after only a single 

 season in the field. 



It is true that the studies of Niagara and the Great Lakes, which Gilbert carried over from 

 the previous decade into the nineties and later, were highly illuminating; and had they been 

 advanced from personal to divisional rank and been carried to the point of preparing a complete 

 report on the postglacial history of the St. Lawrence drainage, such a volume would have 

 rivaled the Bonneville monograph; but unhappily his work never went so far as that, and his 

 results, so far as they are published, remain subdivided among many short essays. It can not 

 be doubted that, if he had had the aid of a small corps of assistants in tracing shore lines and 

 lake outlets and if the volunteer workers in various parts of the Great Lakes region had been 

 invited to submit their results to him for correlation, the Great Lakes problem would have been 

 rapidly advanced and essentially completed. A comprehensive study of this kind would, to 

 be sure, have assumed an international character which might have raised certain difficulties 

 in the way of its execution, but paths around difficulties can usually be found when they are 

 wanted; and a cooperative investigation of the St. Lawrence drainage basin by the United 

 States and Canada would have been a fine contribution to international comity. But, as a 

 matter of fact, Gilbert's field studies in the Great Lakes region were not only performed largely 

 without assistance; they were also much interfered with by a variety of distractions. 



Discontinuity of effort thus seems frequently to have characterized his later years, and 

 one cause of the discontinuity appears to have been of his own liking, for it was entirely by his 

 own choice that he undertook several courses of university lectures and various literary tasks, 

 during the performance of which leave of absence was taken from the survey without pay. 

 Interruptions of these kinds always consume more time than is allotted to them; they are like 

 constrictions in a water conduit which diminish its discharge not only by locally decreasing the 

 conduit diameter but also by exciting eddies, and thus dmiinishing the effective diameter of the 

 conduit still further. However, in a later period, just before and after his seventieth year, 

 Gilbert made a remarkable investigation of hydraulic-mining debris in California, the reports 

 on which showed that he preserved even after a severe illness in 1909 and into his old age 

 an extraordinary capacity in continuous quantitative work, and in linking together a long 

 enchainment of causes and effects; but naturally enough this great study did not reach the 

 dignity of the Bonneville investigation, all the observational and much of the theoretical work 

 upon which was completed before his fortieth year. Many other subjects that he treated in 

 later life were of comparatively short range; or if of longer range, his touch upon them was 

 short lived even though penetrating. 



It thus appears that when, on passing his fiftieth year, Gilbert was relieved from adminis- 

 trative work, he did not enter upon any one great task and carry it to completion. His later 

 studies were directed to a variety of topics, each of which was treated admirably as far as it was 

 followed, but none of which was investigated with monographic thoroughness. His work on 

 Niagara and the Great Lakes was longest continued and carried nearest to completeness, but it 

 was intermittently pursued and, as already noted, the results gained were not brought together 

 in consecutive and harmonious form. Some of his most significant observations, such as those 

 concerning the cross-spur channels cut by the proglacial lake discharge in central New York, and 

 those concerning the Algonquin and Nipissing outlets across the Province of Ontario, remain 

 for the most part in unpublished notebook records. Gilbert stood at this time unquestionably 

 at the zenith of his scientific achievements; he enjoyed to the fullest extent the confidence and 

 respect of American geologists, his relations with whom were, as already noted, happily extended 

 through the meetings of the Geological Society of America, then newly organized. His in- 

 fluence on geological science continued for years to be most beneficent in the way of inculcating 

 by example the very ideal of unprejudiced objective methods in scientific work; but his native 

 genius was not employed to its fullest advantage in the discontinuous studies that he undertook. 

 It was as if the countless distractions during his 10 years of administrative work had so inter- 

 rupted his natural capacity of scientific study that he found difficulty in returning to large 

 problems involving long-sustained mental effort. 



