G. K. Gilbert — Inculcation of Scientific Method. 293 



height might be carefully measured at two points and the dif- 

 ference of altitude compared with the total throw of the inter- 

 vening post-Bon neville faults. The second of these tests was 

 applied, and with success. By means of the surveyor's level 

 the height of the old shore above the water surface at the shore 

 of Great Salt Lake was measured at two points twenty miles 

 apart. One of these points is on the Wasatch range near Salt 

 Lake City; the other is on the next range west, the Oquirrh. 

 The only post-Bonneville fault between them is that at the base 

 of the Wasatch, and its throw is there about fifty feet, the west 

 side having gone down. If then faulting is alone responsible 

 for shore-displacement, the beach on the Oquirrh range should 

 be fifty feet lower than that on the Wasatch. The measurement 

 however showed it to be twenty-eight feet higher, and thus 

 demonstrated a difference of seventy-eight feet to be referred 

 to undulation/ 



Thus a step was made in advance, but the resulting position 

 was not final, for the inquiring mind could find no satisfaction 

 in the knowledge that crust undulation and crust faulting were 

 conjointly efficient, so long as both these remained without 

 explanation. No new hypotheses were at once invented, but it 

 was determined to continue observation until the solitary phe- 

 nomena at command were expanded into a group, and to seek 

 new light in the classification of this group. As the basin was 

 traversed in the conduct of the general investigation of the old 

 lake, a search was made for the records of recent faults and at 

 every opportunity the height of the shore was accurately 

 measured. Six such measurements were made in the imme- 

 diate vicinity of Great Salt Lake, the lake affording a common 

 datum plane. Ten others were made on the lines of railways, 

 where the leveling data of the railway engineers could be util- 

 ized. At some points the height was found greater than on the 

 Oquirrh, at others less than on the Wasatch, the range from 

 highest to lowest being 168 feet. 



Faults were discovered at the bases of numerous mountain 

 ranges, but none of them are so great as that along the Wasatch, 

 and nearly all are very small. None were found associated 

 with the half-buried mountains of the center of the desert, and 

 yet on these same mountains are the highest shore records to 

 which measurement was carried. 



In general it was found that the displacements recorded by the 

 shores have been much larger than the displacements demon- 

 strated by faults, so that faulting can be appealed to in expla- 

 nation of shore displacement only to a small extent. It was 

 found that the throw of the faults was in some cases opposed 

 in direction to the total deformation on the shore-line and in 

 other cases coincident. For these reasons faulting was provis- 



