ABSTRACTS AND DISCUSSIONS OP PAPERS 47 



trenches of the same order occur in most of the great canyons of the western 

 Sierra slope. Their youthful aspect, coupled with the fact that they are still 

 actively being deepened by the rivers, points strongly to their initiation in 

 consequence of rapid tilting at a time which can scarcely have been more re- 

 mote than the beginning of the Quaternary period. The amplitude of this 

 uplift at the eastern edge of the Sierra block may be roughly estimated from 

 the inclination of the younger profile of the Merced. That profile appears at 

 least four times as steep as a graded profile of the river might be expected to 

 have been. It is to be inferred, therefore, that the range crest at the head 

 of the Merced stood, prior to the last uplift, only one-fourth as high as it now 

 stands. Mount Lyell, instead of 13,090 feet, had an altitude of only some 

 4,400 feet. This, it will be observed, is 2,000 feet less than the present altitude 

 of Mono Lake (6,417 feet). It would follow, then, that the regions to the east 

 of the Sierra Nevada have also been uplifted broadly by several thousand feet 

 since the end of Tertiary time. 



The Sierra uplift indicated by the older profile of the Merced is considerably 

 less than that indicated by the younger profile and probably did not exceed 

 2,500 feet. 



Presented in abstract extemporaneously. 



The Society adjourned about 12.30 o'clock and reconvened at 2 o'clock. 



TITLES AND ABSTRACTS OF PAPERS PRESENTED BEFORE THE AFTERNOON 

 SESSION AND DISCUSSIONS THEREON 



The Society reconvened at 2 o'clock, with President Coleman presiding 

 and Charles P. Berkey acting as Secretary, and took up the consideration 

 of scientific papers. 



GEOLOGICAL TRANSFORMATIONS OF PHOSPHORUS 

 BY ELIOT BLACKWELDER 



{Abstract) 



Phosphorus migrates widely in and upon the earth, passing meanwhile through 

 a varied and interesting series of metamorphoses. An attempt will be made 

 to outline these changes, beginning with the crystallization of apatite and 

 other phosphates in igneous rocks and primary veins, following them through 

 the circulation of ground-water to the ocean, there to undergo an all but end- 

 less series of reincarnations in the bodies of organisms, and ending temporarily 

 with the fixing of the element in the form of phosphatic sediments. Subse- 

 quent changes take place in the latter, both near the land surface and in the 

 deep interior of the earth. The various known types of phosphatic deposits 

 may be placed rather definitely in this metamorphic cycle. 



Presented in abstract extemporaneously. 



