MOCHA-STONES. 
103 
Moss-AGATES AND Mocua-stongs.—The beautiful siliceous 
pebbles called Moss - agates, 
and Mocha-stones, will so often 
come under the notice of the 
collector, that, although but 
extremely few, if any, of these 
objects contain organic re- 
mains, the arborescent sub- 
stances they inclose being 
merely metallic oxides, a few 
remarks on their nature may 
be expected. The late Dr. 
Macculloch paid considerable 
attention to the investigation 
of these bodies, and believed 
that some of the objects im- 
bedded in the pure and com- 
pact quartz were really of ve- 
getable or animal origin ; the 
specimen figured Lign. 11 is 
of this kind ; the fossils be- 
ing apparently cellular cryp- 
togamous plants. In Geol. 
Trans. vol. ii., other exam- 
ples are figured and described 
by the same sagacious ob- 
server. 
\ 
| 
I 
i} 
=: 
Mf ili 
HA HY 
A, LA 
\Y 
Lien. 10. DELESSERITES (FUCOIDES) 
LAMOUROUXII. 
, : Liar . (Veg. Foss. Br. 
Mr. Bowerbank is Tertiary. Monte Bolca. (Veg. Foss ) 
of opinion that spongeous structure enters into the composi- 
tion of almost all the moss-agates, and I have no doubt that 
in some instances such organisms are present : but in by far 
the greater number of agates and mocha-stones the inclosed 
bodies are mere crystallizations; they are arborescent or 
dendritical oxides of manganese, copper, chlorite, iron, &e. 
M. Brongniart, who carefully examined a great number 
of agates and pebbles, with the view of determining if vege- 
