44 
GroLocic TIME-SCALE (lower portion). 
Names italicised indicate epochs, representatives of the 
fossil life of which are shown in exhibits Nos..8, 9, 10 
and Il. 

Neosilurian. Lower Helderberg. 

Niagara.* 
Silurian. Eosilurian. | Clinton. 
| Medina. 

Hudson. ° 
Utica. 
Trenton. 
Black River. 
Birdseye. 
Neoordovician. 
Ordovician. 

| | Upper Chazy. 
Middle Chazy. 
| Eoodrdovician LE Oey, 
ee Upper Calctferous. 
| Middle Calciferous. 
Lower Calciferous. 


Potsdam. 
Cambrian. Neocambrian. 

* Including Guelph and Salina. 
9g. NEoORDOVICIAN. Invertebrates from the Black River, Tren- 
ton and Utica formations of the Lake Champlain region. 
Collection of 1895. Exhibited by Theodore G. White. 
Special features : 
a. Fossils indicative of particular zones of the Black 
River limestone from its lower to its upper limits, 
as: 
1. Leperditia from base of the formation at 
Button Bay Island, Vt., and Chazy, N. Y. 
2. Strophomena filitexta from Button Bay 
Island, Vt. 
3. Stromatocertum and Columnarta from the 
above localities, forming at the former locality a 
coral reef band two feet in thickness. 
4. Maclurea, a peculiar Black River species 
from Chazy, N. Y. 
