88 
THE GEOLOGIST. 
What is its history ? Bones of animals, wo know, arc formed oi 
phosphorus and lime (phosphate of lime), but not a trace, save 
rarely a few teeth of sharks or tiny vertebrfE of fish, of bones of any 
living thing of earth, or air, or sea is there — so far as we can see ; 
and yet there are tons and thousands of tons of what we only know 
in an organic form as bone-substance. There are the gnarled riddled 
boughs of trees, charred into radiate blackness in the lapse of incom- 
prehensible time, and these are rich in, nay, permeated, soaked, so to 
speak, with the phosphatic matter, for they offer to the chemist's test 
as much per cent, as these hard, black-brownish lumps. There are 
broken phosphatic casts of the rough rugged Ammonites mammilaris 
Lign. 12. — Ammonites mammilaris. From the " Junction- (phosphate of lime) bed." 
in numbers, bedaubed and patched with phosphatic concretions, but 
nothing else, save of shell-fish a few stray straggling Inocerami or 
Dentalia, which only occasionally occur. 
These phosphate-nodules, I should think, must have been derived 
from some organic substance, the great accumulation of which at 
one horizon, however, is very remarkable. Could the perishing car- 
cases of gigantic Ammonites, such as the A. mammilaris in its adult 
