118 GROVE KARL GILBERT— DAVIS 



Black Hills, they are given no special name, although they are manifestly neither consequent, 

 antecedent, nor superimposed. The same is true of the longitudinal and presumably subse- 

 quent valleys that follow the weak schists between the quartzite ridges of the unroofed Archean 

 area. Perhaps it is because most of these manifestly subsequent valleys have no streams that 

 they were given no systematic names. Second, mention is made of the disagreement between 

 the crest of the original dome, which as structurally restored lay near its eastern side, and the 

 present divide between the east-flowing and west-flowing consequent creeks, which lies 15 or 

 20 miles farther west. This is explained as the result of a displacement of the line of maxi- 

 mum uplift from its original position, as if the creeks were consequent upon the first uplift and, 

 thus being located antecedent to the later and more eastward uplift, held their courses across it. 



When the displacement began its summit was necessarily a divide or water-shed, from which the water 

 flowed in all directions. In the absence of any disturbing cause this water-shed would remain as steadfast as 

 the drainage lines all through the period of denudation. Knowing of no disturbing cause, we may assume that 

 the existing water-shed in the Hills holds the same position as the original water-shed, and marks, therefore, 

 the position of the summit of the uplift at the time of its inception. ... It would appear that the portion of 

 the uplift which took the lead at the start was afterward overtaken and exceeded by another portion, so that 

 the present summit or axis of upheaval is not the original axis of upheaval (217, 218). 



This conclusion appears to overlook the principle, announced in the Henry Mountains 

 report, that steep slopes are eroded more rapidly than gentle slopes; and that an unsymmetri- 

 cal divide between two streams must therefore be slowly pushed from its steeper slope toward 

 its gentler slope. In a word, the shifting of divides by headwater erosion is not here considered; 

 it is not mentioned even in connection with the statement that "in a few cases, [radial conse- 

 quent] streams of considerable size have so far shifted their courses as to form unions with 

 each other before escaping from the foot-hills, but such instances are rare"; nor is any special 

 attention given to the longitudinal stream courses in the Red Valley by which such unions 

 appear to have been effected. Here, as before, the moral to be drawn is plainly that, great as 

 were the contributions which Gilbert made to the rational treatment of land sculpture, the 

 subject was so little developed in his earlier years that even he did not develop it fully. 



PERSONAL ITEMS 



During the two-year period of these divers occupations, Powell's survey would appear to 

 have been conducted in a very personal manner, if one may judge by certain entries in Gilbert's 

 diaries. One for February 2, 1878, reads: "Powell still owes, unpaid salary, $217.50"; and 

 three weeks later: "Major Powell requests me to wait until May 1st before receiving more of 

 my pay. I have now received all of my salary for 1877 except $5.00 and none for 1878. " The 

 survey must indeed have been in a peculiar financial condition if it had to leave unpaid a bal- 

 ance of $5 due to a valued member, who surely thereafter deserved to be called a trusting as 

 well as a trusted friend of the director. It is possible that these irregularities, not to say un- 

 certainties, of payment prompted Gilbert at least to consider a change to university work, for 

 in his diary for 1879 a summary for the year previous, during which he had reached his 35th 

 year of age, includes the following record: "Visited Providence, R. I., to talk about Profes- 

 sorship, Mar. 25-27. " In view of the diversion of a large share of his attention a few years 

 later from research to administration, it is open to question whether geology did not suffer 

 more by his retention of a place in Government service than by his nonacceptance of a univer- 

 sity position. He would have made a delightfully inspiring teacher, for his Hnppy manner 

 when speaking at geological meetings in Washington was already exerting a strong influence 

 over younger men, who were quick to recognize his mastery of geological philosophy; and he 

 had moreover an extraordinary capacity for making difficult subjects easy by analyzing the 

 successive steps and stating each one separately and clearly, so that it could be surmounted 

 with facility. Surely no professor in the land would have presented his science more objec- 

 tively, none would have attacked his problems in a more calm and dispassionate spirit, none 

 would have presented conclusions more free from personal bias. But had he taken up uni- 

 versity work he ought to have had a research professorship; and it does not appear that such 

 a position was opened to him. 



