6 ° 
* 
(c) Madrepores of numerous species transformed to 
agate, or semipellucid silex, of remarkable beauty and 
variety. The view of them in their exquisite forms and 
fractures, excites a suspicion that they are not conversions 
from lime; but on the contrary, origin«! formations from 
radiary animals secreting silicious matter for their habita- 
tions. 7 
(cc) An elegant agatized terebratula, from the coast of 
Coromandel; from the Baron Lescallier, late Consul Ge- 
neral of France; accompanied by a note in the handwriting 
of that erudite, modest, and accomplished man. 
7. Various samples of agatized, or silicified wood, from 
other sources. 3 : 
8. A piece of the buhr-quartz of Georgia, recommended 
for mill-stones, and imported for the preparation of flour 
from wheat to New-York. It is filled with the shells of 
marine molluscas, which wear away fast by attrition, and 
render the bread gritty. 
9. A portion of red sand-stone, from the secondary for- 
mation of Belleville, near the Passaic river, ten miles from 
New-York city ; containing an elegant impression of a 
fern, ten inches long. 
~ 10. A mass of sand-stone from Chenango asus: New- 
York, exhibiting in its fracture, a figure that has been call- 
ed the screw-auger by the discoverers, but which, on exa- 
mination, appears to be an extinct species of the terebrum, 
or screw-shell.—U. Tracy. 
11. An instructive assemblage of madreporites in fetid 
lime-stone, from Caledonia, New-York.—Drake. 
12. Terebratulites, and other rare articles, from West- 
chester county, New-York, at Mount Pleasant; discovered 
ten feet under ground. Large article, .full of nitty impres- 
sions of pectinites, and other relics. 
13. Other pectinites and terebratulites. 
14. Yet other impressions of the same kind. 
15. A box, containing specimens illustrative of the geo- 
logy of Nantucket; consisting of two ‘species of univalve 
