EXPLANATION OF THE DIAGRAM, 
A. Entrance to the roam. 
B. B. Stairs to gallery. 
CCCCCCCC. Windows. 
D. Table. 
EEEEEEEEE. Vertical cases standing against the 
side of the room. 
The figures indicate the Tabular cases, with ths- 
contents, as follows : 
1. Primary system. 
2. Taeonic (Taghconick) system. 
NEW-YORK SYSTEM. 
3- 1* * * § Potsdam sandstone. 
4- 2. Calciferous sandrock. 
5- 3. Black-river and Birdseye limestone. 
6- 4. Trenton limestone. 
7- 5. Utica slate. 
8- 6- Hudson-river group. 
9- 7. Grey sandstone. 
10- 8. Oneida conglomerate. 
11- 9. Medina sandstone. 
12- 10. Clinton group. 
13- 11. Niagara group. 
14- 12. Onondaga-salt group. 
15- 13. Waterlime group. 
16- 14. Pentamerus limestone. 
17- 15. Delthyris shaly limestone4 
18- 16. Oriskany sandstone. 
19- 17. Cauda-galli grit. 
20- 18. Schoharie grit. 
21- 19. Onondaga limestone. 
22- 20. Corniferous limestone. 
23- 21. Marcellus shale. 
24- 22. Hamilton group. 
25- 22. Hamilton group.!; 
26- 23. Tully limestone. 
27- 24. Genesee slate. 
28- 25. Portage group. 
29- 26. Ithaca group. 
30- 27. Chemung group. 
31- 28. Catskill group or Old Redsandstone. 
CARBONIFEROUS SYSTEM. 
32. Conglomerate. 
33. Coal and coal plants from Pennsylvania.^ 
34. Red sandstone and associated trap rocks of 
Southern New-York. 
35. Boulders. 
36. Sands and clays. 
37. Marl and modern tertiary fossils. 
* The second series of numbers are those attach¬ 
ed to the cases in the room, showing the succession 
among the rocks of the New-York system. _ 
t The Encrinal and Upper Pentamerus limestone, 
are not separated in the arrangement. 
t Two cases are occupied by the Hamilton group. 
§ The New-Yolk series ends with the Conglome¬ 
rate, and these specimens from the coal fields of 
Pennsylvania are introduced for the purpose oi 
showing the relative situation of those rocks. 
