REMARKS ON THE BOTTOM DEPOSITS (Plate la). 



By Sir JOHN MURRAY, K.C.B. 



Our knowledge of the deposits covering the floor of the tropicfil Pacific 

 has been much increased by an examination of the soundings taken by the 

 U.S.S. "Albatross" in 1899 and 1900, under the direction of Mr. Alexander 

 Agassiz. It is true that no new type of deep-sea deposit has been dis- 

 covered, but the distribution of the deposits has been considerably modified. 

 The principal result, perhaps, is the enormous extension, towards the east, 

 of the Radiolarian Ooze area discovered by the "Challenger" between 5° 

 and 15" N. lat. and 145° and 155 W. long. Our examination of the samples 

 recenth' collected, and of those collected in 1891, by the "Albatross," 

 seems to show that this Radiolarian Ooze area extends uninterruptedly 

 through about 85' of long, into the Gulf of Panama (where it occurs in 

 comparatively shallow water), forming a band varying in width from 5° to 

 12° of lat. Another result is the eastern extension also of the Globigerina 

 Ooze area at the equator, and the introduction of Pteropod Ooze around 

 the coral islands of the Paumotu and Marquesas groups. The numerous 

 soundings taken by the " Albatross " among the coral i.sland-groups show 

 that in many cases deep water, where the bottom is covered by Red Clay, 

 approaches very close to the islands, but a curious circumstance regarding 

 the .samples collected in the vicinity of the coral islands is the large pro- 

 portion of very small samples, from which all fine clayey and calcareous 

 material has apparently been washed away during process of collection, so 

 that it is often impo.ssible to say, fjom the insufficient quantity of incoherent 

 material at our disposal, what the precise condition of the deposit in situ 

 may be. The " Albatro.ss," like the " Challenge)-," cros.sed the typical Red 

 or Chocolate Clay area, the trawl having, at Station 173 in lat. 18' 55' S., 

 long. 146 32' W., 2440 fathoms, brought up a large supply of stiff choco- 



