MKMOKIAL OF U. K. GILHKRT 41 



tain c-hapters, in wliicli his inatuio views are presented and the whole 

 conception more eomprehensividy stated than hefore. It may be said 

 in passin^^ that additional evidence stroni-ly confirms the conclnsions 

 reached in the Wheeler Snrvey reconnaissance. 



Following the Harriman Alaskan P^xpedition, (Jilhert turned again 

 to the Pacific coast. In VM)'-) he undertook some investigations of the 

 glaeiation and morphology of the Sierra, from which several valuable 

 short papers resulted. In 11)04 the ('alifornia ^Miners' Asociation peti- 

 tioned the President of the United States to instruct the Geological 

 Survey to make a general study of the problem of the transportation of 

 debris in its relation to mining, agricultural, and transportation inter- 

 ests. The work was undertaken and Gilbert assigned to the problem. 

 He particularly welcomed the assignment for the opportunity it would 

 give him to apply quantitative and experimental tests to the qualitative 

 and deductive conclusions wliich he had reached in his chapter on 

 "I and sculpture/' in the Henry ^lountains report. A laboratory was 

 established at Berkeley, field studies were carried out in the Sierra, along 

 the California stream>, and about San Francisco Bay, and the results 

 were about ready for presentation when the first physical breakdown 

 came, in 1900. 



Gilbert's most obvious anxiety at that time was the fear that the work 

 which he had done migiit l)e lost, and it was a source of supreme satisfac- 

 tion to him wiien the two papers. Professional Papers Numbers 86 and 

 105, in which these results were prcvsented, had been completed. 



The first of these papers is a record of experimental data and a mathe- 

 matical and ])hysical discussion of them, too abstruse for the majority 

 of geologists to read ; the general problem is treated in the second 

 volume as a (piantitative discussion of certain physiographic processes 

 and the effects of those processes upon the rivers, valleys, and harl)ors of 

 the region, and thus upon human industry. 



While the del)ris investigations were under way central (California 

 was shaken i)y the eartlnjuake of April, l!M)(i. Gil])ert, in Berkeley at 

 tlie time, took an active pait in the seisinf)logic'al studies which rolh)wed, 

 and, as was practically always tiue when he was engaged upon a general 

 problem, a number of papers, in this case generally brief, resulted. 



With the com])letion of the earth(|uake studies and the report n[)on 

 the del)ris investigations he returned to the familiar field of the "B:i<in 

 ranges," with results already recorded. With the completion of the mo^l 

 important chapter^ of his review of this problem, he must h'lve taken 



