CHEMICAL EVOLUTION OF THE OCEAN 691 



The President declared the scientific program in order. The first 

 paper presented was the following : 



CHEMICAL EVOLUTION OF THE OCEAN 

 BY ALFRED C. LANE 



[Abstract] 



If there is any value in the numerous attempts, by Joly and others, to esti- 

 mate the age of the earth from the accumulation of some salt in the ocean, 

 there must have been a progressive change in the chemical character of the 

 ocean, which might possibly be detected in comparing the waters buried in 

 undisturbed sediments of various ages. 



The paper applies this test to the deepest waters known from various geo- 

 logical horizons in the Lower Michigan and Lake Superior basins. Both basins 

 are as permanent and free from recent igneous disturbance or faulting or 

 inverted siphon circulation, etcetera, as are readily found. 



The proportions of many ions are likely to be changed by reactions after 

 burial. The ratio of chlorine to sodium seems to be among those least change- 

 able, thus: This ratio is in sea water 25,440 (trillion tons) to 14,151 (trillion 

 tons) = 1.77, while in the river waters delivered each year it is 84 (million tons) 

 to 157 (million tons). Whence, unless there 'S some large source of chlorine 

 apart from sodium, or precipitation of sodium apart from chlorine, n years ago the 

 ratio must have been about R = (25,440— .000,084n) /( 14,151— .000,157n). For 

 instance, we have from the Upper Subcarboniferous of Big Rapids R = 2.14, 

 n = 20 million years ; similarly from the Berea grit at Bay City 45 million years ; 

 from the meso-Devonian at Alma 49 million years ; from the Silurian at 

 Manistee 65 million years; from the Upper Keweenawan at Freda 72 million 

 years ; from the Tamarack mine, Lower Keweenawan, 89 million years. These 

 figures suggest some agreement with the hypothesis, but a more careful exami- 

 nation reveals serious difficulties, as is more fully presented in the paper. 



The paper was discussed by J. F. Kemp, A. P. Coleman, and the 

 author. 



The second paper was 



DIKE OF MICA-PERIDOTITE FROM FAYETTE COUNTY, SOUTHWESTERN 



PENNSYLVANIA 



BY J. F. KEMP 



[Abstract] 



The dike occurs on the surface and in the coal mines on Middle run, a tribu- 

 tary of the Monongahela, in the Masontown quadrangle. It cuts the Carbon- 

 iferous to and above the Waynesburg coal seam and reveals eruptive rocks in a 

 hitherto unsuspected region. The petrographic details were briefly given and 

 comparisons were made with other similar occurrences. The full paper will 

 be published elsewhere. 



The author replied to questions by A. C. Lane. 



