Y 
17. Two other oceanic relics, in lime-stone; one of them 
apparently containing large entrochites, and the other a 
water-worn madrepore, shaped almost like a human thigh- 
bone. 

N° If. 
Third Shelf from below. 
1. Aw extensive and instructive specimen of silicified 
wood, from Alabama; remarkable, among other circum- 
stances, for bearing on its surface barnacles and flustras, 
proving it to have lain in the salt water. 
2. A mass of incipient chalk, from the same region. 
The shells can be seen in their progress toward disintegra- 
tion, and of changing to the calcareous carbonate. A thin- 
shelled oyster seems to be the principal material. 
3. A lump of chalk, from the same stratum, where the 
shells have lost more of their original form, by conversion 
to friable earth. 
4. A group of echinuses, or sea-urchins, from the chalk 
formation of Tombigbee. 
5. A group of gryphza shells, not consolidated, from 
the Chickasaw country, where they are said to be very 
numerous. 
(a) Sharks’ teeth, and impressions of shells. Tombig- 
bee, vicinity of Fort Stevens. 
(6) An irregular mass, whimsically figured, showing the 
manner in which chalk runs into the nodular form of flint. 
(c) Pieces of shells, concreted with shelly sand; show- 
ing the constitution of the Bahama islands and shoals; dug 
out of a well forty feet deep, at Nassau, in New-Provi- 
dence island.—M. Hall. 
(d) Pieces of shells, from the shell banks at Rockaway, 
south side of Long-Island, where the clams were brought 
up by the native Indians for food: large heaps yet remain. 
B 
