THE DEPTH AND MARINE DEPOSITS OP THE PACIFIC OCEAN. 77 



calcium carbonate ; otherwise it might equally well have been called a Dia- 

 tom Ooze or a Radiolarian Ooze, so abundant were these siliceous remains. 



Another sample was incoherent and finely granular, as though it had 

 been subjected to a certain amount of washing ; the residue consists princi- 

 pally of Sponge spicules with glauconitic casts and a few Diatoms. 



Another sample is apparently from deep water, as many of the shells are 

 broken. It is mottled light and dark brown, while the residue is chocolate 

 brown from the large proportion of manganese grains. The percentage of 

 calcium carbonate is 70 or 80, and there are many Radiolaria and Diatoms 

 probably equal to 5 per cent. 



The shreds of a label were found in another bottle, and the number 4638 

 could with difficulty be made out. According to the preliminary report. 

 Station 4638 is in Lat. 0° 27' N. ; long. 87° 13' W. ; and the depth is 1450 

 fathoms. The deposit contains 61.51 per cent of calcium carbonate, and is 

 mottled dark and light gray ; many of the Foraminifera shells are broken, 

 and discolored by manganese. 



Another sample which was analyzed gave 53.76 per cent of calcium car- 

 bonate, though in the bottle it had the appearance of a Red Clay ; and the 

 residue is of a chocolate color. 



B. RED CLAY. One sample contained much manganese in the form of 

 small nodules and grains, with a few decomposed volcanic rock fragments, 

 and a few Radiolaria and Diatoms ; no calcium carbonate. 



Another sample also contained no calcium carbonate, and a few volcanic 

 mineral particles and one or two Radiolaria filled with clay were observed. 

 Shreds of a label were extracted from this bottle on which, after the word 

 " depth," the figures 26 — were deciphered, so that it seems not unlikely 

 that the material came from Station 4511 (Lat. 15° 39' S.; long. 83° 27.4' W. ; 

 depth, 2620 fathoms). 



C. RADIOLARIAN OOZE. One sample of Radiolarian Ooze contained 

 about 5 per cent of calcium carbonate (consisting principally of pelagic For- 

 aminifera), and probably less than 5 per cent of mineral particles (volcanic 

 glass and manganese grains). The skeletons of Radiolaria appear to make 

 up probably about one-half of this deposit. 



Another sample contained no calcium carbonate ; the ooze is of a pale 

 green color, and besides the Radiolaria, Diatoms are also very abundant, 

 while mineral particles are few and small. 



