206 



DEPTHS OF THE OCEAN 



as shown by the attached marine organisms and by a slight coating 

 of manganese oxide on the exposed parts. In Fig. 148, which represents 

 a specimen composed of carboniferous Hmestone and chert, the arrow 



points to the man- 

 ganese staining where 

 the exposed and un- 

 exposed parts meet. 



The average size 

 of the stones is about 

 three inches ; only a 

 very few reach six 

 inches in length. As 

 the sounding - tube 

 brought up from the 

 sea-floor at this station 

 a core of ooze nine 

 inches long, we may 

 infer that the tube 

 pierced the deposit to 

 a greater depth than 

 that reached by any 

 of the stones. It is 

 therefore clear that 

 none of the stones can 

 be in situ. They must 

 have been dropped 

 from above into the 

 ooze. 



Many of the speci- 

 mens, as represented 

 in Fig. 149, must have 

 stood on end in the 

 ooze, which is not the 

 natural position they 

 would have assumed 

 if dropped on the 

 present surface of that 

 deposit. The infer- 

 ence seems obvious 

 that originally they 

 fell into a soft ooze 

 in which they were completely buried. The stones would naturally be 

 arranged along the lines of least resistance to friction, so that many 

 would be entombed end on or edge on, like those illustrated in Figs. 

 149 and 1 50. Subsequent current action has removed part of the 

 material in which they were embedded, and has been powerful enough 

 to prevent further accumulation of ooze at the spot where they were 

 dredged. Since the ooze contains IJ per cent of insoluble material, the 

 theory of the removal of the deposit by solution is improbable. 



Among the materials distributed by human agency dredged from 



Fig. 148. — Stone with staining ok Manganese, the 

 arrow showing the position of the surface of 



THE DEPOSIT IN WHICH THE SPECIMEN HAD BEEN 

 EMBEDDED. 



