1883.] 471 (.Crosby. 



until comparatively recent geological periods such beds have not been 

 formed." 



It must have occurred to many of the readers of the paper just 

 quoted that Sir Wyville has failed to exhibit any sufficient reason 

 for abandoning his earlier view that the deep sea clay and ooze 

 are not essentially unlike some of the argillaceous and calcareous 

 rocks exposed on the continents. But it is not my purpose to 

 further contest this point ; for, although believing that the deep 

 sea deposits are matched lithologically among the formations on 

 the land, I do not claim that the chalk, for example, is, in conse- 

 quence, necessarily a consolidated abyssal ooze. Although this 

 conclusion is much strengthened by the fact that the chalk does 

 not resemble any shallow water deposit of the present day half so 

 much as it does the Globigerina ooze. Still, nothing is truer in 

 geology than that very similar effects may flow from very dissim- 

 ilar causes. 



But the point that I wish to raise now is embodied in the fol- 

 lowing question : Are there any deep sea deposits ? If, as I be- 

 lieve, this question may be fairly answered in the negative, at 

 least as regards the truly abyssal portions of the sea, then the 

 argument that these sediments are not represented on the conti- 

 nents ceases to have any weight, in fact, it no longer exists. 

 Now nothing has been more clearly demonstrated by the deep 

 sea explorations carried on during the last fifteen years than that 

 the abyssal sediments, and especially the red clay, are accumu- 

 lating with extreme slowness. Over the red clay areas the 

 dredge brings up large numbers of nodules of very irregular 

 forms varying in size from minute grains to masses weighing 

 several pounds and consisting chiefly of the iron and manganese 

 per-oxides arranged in concentric layers in the matrix of clay, 

 around a nucleus formed by a shark's tooth, or a piece of bone, or 

 an otolith, or a piece of siliceous sponge, or more frequently a 

 fragment of pumice. Sir Wyville Thomson has shown that we 

 have in these nodules, and in some of their nuclei, " ample evi- 

 dence that this abyssal deposit is taking place with extreme slow- 

 ness ; for the nodules are evidently formed in the clay, and the 

 formation of the larger ones and the segregation of the material 

 must have required a very long time ; while many of the shark's 



