Mineralogy and Geology. 425 
phosphates of alumina, iron, .and magnesia, organic matter, silica, etes 
The other variety, generally of a broad concretionary structure, is of a 
white or yellowish- white color, containing a little carbonate of lime, sul- 
perceptible. The term “amorphous” can only be applied to those com- 
paratively rare varieties in which these characteristics are mixed, or 
entirely indistinguishable on account ~ the uniformity in color of the 
oolitic grains and their cement. Again, as the guano is interlaminated 
with ordinary coral limestone, and I hone found all the _ it 
presents to be ae attributable to atmospheric agents, there is no call 
for the conjecture of a “high temperature,” nor for the Tallow strange 
i “T loo i 
contact with eases or steam, and under great press 
The “several kinds of npiled ” sco Dr. Phipson abe mentions among 
the fossils enclosed in the guano, belong entirely to the coral limestone 
snderitodd from shal has a stead stated. The So mbrero fai: 
phates, as aly thee phospha ic guano, and as little en ntitléd to rank as a 
new speci r on cannot possibly have examined with any care 
a single cargo,—I venture to say, not even a single ton ; for there is no 
natural standard by which a representative specimen could be “w 
chosen” or chosen at all. 
Further, Dr. Phipson does not inform us of the methods used by him in 
the vailing uncertainty among chemists as to the most exact 
of sitions ng phosphoric acid, in the presence of lime, iron, 7 civimion, 
also on account of some other curious results arrived at. Firstly, as to 
the 9 ) per r cent of water: it is to be presumed that the “ well choad 
men” was carefully dried to remove moisture, which varies several per 
cent in different varieties. It is also to be presumed, from the analysis, 
part of this 9 per cent of water may combined,® and that = two 
equivalents of water, combined in the «sulphate of lime,” have been 
ucted from the gross amount. The variety of this guano which I 
Notwithstanding that the presence hosphoric acid in the filtrate, after long 
shine maqpengts. Pron 7 hovel the eietilcs Of this nals at least some com- 
