MUSEUM OF COMPARATIVE ZOOLOGY. 43 
They are similar to the grains found in phosphatic nodules dredged off 
the Cape of Good Hope and elsewhere by the “Challenger,” and iden- 
tical in their physical and chemical properties to the phosphatic grains 
in cretaceous rocks. 
The manganese is infiltrated through the whole mass of the concretion, 
appearing in the microscopic sections in the form of dendrites or concre- 
tions, sometimes opaque, sometimes black-brown, and slightly transparent. 
The phosphatic grains are sometimes enclosed in the manganese. 
The “Challenger” dredged on several occasions, especially off the 
Cape of Good Hope, concretionary masses like that above described, but 
very much smaller. Phosphatic nodules were always found in the 
deposits in depths less than 1,500 fathoms, near continental shores, but 
never in the deeper deposits far removed from land. 
An analysis of a portion of the above concretion by M. Klement, 
Brussels, gave as follows : — 
Phosphoric acid (P,O,) . . . . . . 23.53 
Carbonies atiwnQ@Os). esheets 
Sal plriiestay (SOs), Mo st (22D 
Fluorine pte Reeeeg (Pet) me. A ioe case 
Chineine Jils ewes a ate ke es OG 
inten eae (hea aee 2 NF bee Sa |nces BBB 
NERANCSIN (MEO aera. eee a fe ee! LOT 
Tnpbliple-ftesidua: sso.) u, km ye oe § OFD2 
PUDSRSON MOMALION Apes 4 sine ape eat et kD 
100.65 
Oxygen corresponding to Fluorine — 0.96 
“corresponding to Chlorine — 0.04 
99.65 
Atomic Ratios. 
ee a See Ee ee oe eee eee ee 
1 ARTE RE Oe 2 ama aay Ty ga 07 | 
SLE Re eae nn a ee 57 $ 1866 
RM ark teas Ys 5s, owe Ree! ea 
AN Wacute rs aek i 
eM ins forth. live 5 ve, Labia’, Dna: 
Mg te 50 } 1914 
The substance analyzed also contained traces of silica, of iron, of 
alumina, and of manganese. 
