322 



THE ATLANTIC. 



[chap. v. 



No. 14.— Station XVII. Lat. 20° 1' N., Long. 52° 32' W. Depth, 

 2385 fathoms. Bottom temperature, 1°*9 C. Chemical composition: 



Loss on ignition after drying at 230° F 6'84 



Alumina 2-69 



Ferric oxide 9'06 



Portion soluble in Calcium phosphate 1 "74 



hydrochloric acid ■{ Calcium sulphate 0"81 



= 83"44. Calcium carbonate 58"40 



Magnesium carbonate 0'68 



Silica lOOV 



Portion insoluble "| 



in hydrochloric j^ 



acid = 9-72. j 



Insoluble residue, principally alumina and ferric oxide, 



with silica 9-Y2 



100 '00 



A red clay, containing amorphous clayey matter, with oxide of iron, 

 and many small particles of sanidine, angite, magnetite, and quartz ; a 



few grains of manganese peroxide. Many pelagic foraminifera of 



the genera Globigerina, Pulvinulina, Sphceroidina, etc. ; coccoliths and 

 rhabdoliths. 



No. 15.— Station XVIII. March 10th. Lat. 19° 41' N., Long. 55° 

 13' W. Depth, 2675 fathoms. Bottom temperature, l°-6 C. Chem- 

 ical composition : 



Loss on ignition after drying at 230° F 7'75 



f Alumina 8-2,5 



Ferric oxide 11 "37 



Portion soluble in Calcium phosphate 0-42 



hydrochloric acid ^ Calcium sulphate 0'52 



= 6000. Calcium carbonate 15-78 



Magnesium carbonate 1 "41 



Silica 22-25 



f Alumina 7-00 



Ferric oxide 2-50 



Lime 0-57 



Magnesia 0-38 



t Silica 21-80 



100-00 



A red clay, containing amorphous clayey matter, and small particles 

 of augite, feldspar, hornblende, and magnetite ; a few grains of manga- 

 nese peroxide. A few broken tests of pelagic foraminifera, cocco- 

 liths, and rhabdoliths. 



No. 16.— Station XIX. March 11th. Lat. 19° 15' N., Long. 57° 47' 



Portion insoluble 



in hydrochloric 



acid = 32-25. 



