198 L. Y. Plrsson — Geology of Bermuda Island ; 



be taken to the conclusion regarding those rocks wholly 

 immersed, the question naturally arises in one's mind if the 

 absence of decomposition products in those rocks constantly 

 wetted by the surf and in many stream beds may not be due, 

 in part at least, to erosion, as noted above." 



Thus if the rocks are entirely immersed, in Merrill's opinion, 

 oxidation will be prevented. 



As will be shown later under the petrographic description 

 of the Bermuda lava, this basalt when wholly immersed in sea- 

 water does not remain unchanged, but the alteration is a very 

 different one from the ordinary decay and oxidation of weather- 

 ing. 



Joly* tried the action of both fresh and salt water on basalt, 

 but his experiments had the object of ascertaining its relative 

 solubility in the two fluids. He does not mention any results 

 of oxidation, and one must conclude that no notable effect of 

 this kind occurred. 



Chamberlin, -j* in mentioning this subject, says : " In the 

 main, the ocean waters protect the sediments from weathering 

 and similar changes, except as organic matter buried with them 

 induces change." 



The reports of the Challenger Expedition offer contributory 

 though not direct evidence pointing to the same conclusion. 

 In those parts of the ocean near the lands where red clays 

 occur they are regarded as products of land waste, while, as 

 Chamberlin remarks,^: u the blue muds indicate lack of oxida- 

 tion, or perhaps deoxidation." 



The red clay on the floors of the abyssal ocean basins would 

 appear to be an exception, but opinion regarding the origin of 

 this deposit is still unsettled, some holding it chiefly as the 

 remains of hard parts of organisms, while others, who have 

 most studied it, believe it to be chiefly of volcanic origin. It 

 has also been suggested that it may be largely eolian dust. In 

 the latter case, as a product of land waste it would be oxidized, 

 and it is to be noted that if of volcanic origin it may also have 

 been oxidized before settling into the sea-water. It may also 

 be suggested that it may be partly cosmic dust in origin and in 

 some part metallic in character. Particles of metallic iron 

 might be oxidized passing through the atmosphere, or become 

 so later by reacting with water, and give the red coloration. 



The chemistry of the sea is an extremely large and complex 

 subject, and it is more than probable that the processes taking 



* J. Joly : Some Experiments on Denudation by Solution in Fresh and Salt 

 Water. Proc. Eoy. Irish Acad., xxiv, Sec. A., pp. 21-23, 1902. 

 \ Chamberlin and Salisbury, Geology, vol. i, id, 360, 1904. 

 JLoc. cit., p. 363. 



