Qe BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
These genera may be divided into two groups, first those appearing 
first in the Walchow and Kunda in Russia, and second, those making 
their first appearance in the Wierland in Russia. In the first group we 
find Eoharpes (also in Beekmantown), Remopleurides, Nileus, 
Ceraurus, Nieszkowskia, and Pterygometopus. In the second group 
are only Lonchodomas, Pseudosphaerexochus, Sphaerexochus, and 
Sphaerocoryphe. Cybeloides, Pliomerops, Vogdesia, and Heliomera 
are all derived from forms appearing first in the lower group in Russia. 
From this analysis of the Chazy fauna it appears that, while the 
fauna is in very large proportion of American origin, it has present in 
it a considerable Russian element which is largely derived from genera 
present in the Walchow and Kunda formations. Why certain genera 
such as Echinosphaerites, Oxoplecia, Plectambonites, and Christiania 
from Russia, and Tretaspis, Nidulites, and Agnostus from Scandi- 
navia, which reached North America somewhere about this time, did 
not get into the typical Chazy is a perplexing question. So far as 
bottom control is concerned, there seems to have been no barrier, and 
only two possible explanations occur, namely, either their natural 
habitat was fully occupied, or they did not reach America till later 
than the time of the typical Chazy; the latter explanation seems, in 
view of all the facts, the more probable. 
DETAILED SECTIONS IN RUSSIA. 
Sections arranged in order from east to west. 
SECTION ON THE WatcHow. (Given by Lamansky (29)). 
Bi, Thick-bedded compact limestone at Sapolek and 
Bylstchina, and at the base of the quarries at St. Mich- 
ael Archangel. 6 meters = 18.35 m. 
Biss. Rusty and spotted limestone at the base, followed 
by one or more layers of “Linsenschicht,”’ these being 
succeeded by red and yellow spotted layers. The Linsen- 
schicht is one meter above the base. 3.5m. = 12.35 m. 
Bia. Bluish green limestone with fine-grained glauconite at 
the base, but none above. 3m. = 8.350% 
B,,,- Compact limestone with some glauconite. Loses 
compactness quickly on weathering. 2.4 to 2.7 m. = 5.85 m. 
