DESCRIPTION OF DEPOSIT 215 



geographer, and others interested in marine deposits, 

 it is specially important that descriptions should give 

 as nearly as possible the proportions of the various 

 constituents of which the deposit is made up, as well 

 as the size of the mineral fragments. This, it is 

 believed, can best be accomplished by the method 

 adopted in describing the " Challenger " collections, as 

 set forth in the following model : 



H.M.S. " Challenger." 



Station, 338. March 21, 1876. 

 Lat. 21 15' S. ; Long., 14 2' W. 

 Depth — 1,990 fathoms. 



Globigerina Ooze. — White, with slight rose tinge, 

 granular, homogeneous, resembling chalk when dry. 



Calcium Carbonate (92-54 per cent.). — Globigeri- 

 nidae, Pulvinulina (8o-oo per cent.) ; Miliolidae, Textu- 

 laridae, Lagenidse, Rotalidae, Nummulinidae (i-oo per 

 cent.) ; otoliths of fish, Gasteropods, Lamellibranchs, 

 Pteropods, Heteropods, Lepas valves, Ostracods, 

 Echinoderm fragments, Polyzoa, Coccoliths, Rhabdo- 

 liths (11-54 P er cent.). 



Residue (7-46 per cent.). — Reddish-brown. 



Siliceous Organisms (i-oo per cent.). — Sponge spi- 

 cules, Radiolaria, imperfect casts of Foraminifera, 

 Astrorhizidae, Lituolidae, a few Diatoms. 



direct from the sounding tube, and it should be noted whether 

 the sample is taken from the superficial or the deeper layers. 

 With the knowledge we now possess it is possible for an expert 

 to tell approximately the latitude, longitude, and depth 

 from which a deposit has been procured. When, then, a 

 sample bears a label showing a Globigerina ooze, for instance, 

 from a depth or latitude which does not accord with experi- 

 ence, it raises suspicions of mislabelling. This has frequently 

 occurred with samples labelled on the corks, which have been 

 interchanged. 



