Fauna of the Cliffwood Clays— Weller. 179 
From the evidence just summarized, the conclusion is 
drawn that the drunilins of the JNIenominee area were pro- 
duced by ice erosion from a previously deposited till sheet. 
This explanation is essentially in harmony with the theory 
of the origin of drumlins advanced several years since by 
professor Shaler. 
Attention will also be invited to the importance of ice 
erosion in shaping the topography of glacial deposits in other 
regions. 
FAUNA OF THE CLIFFWOOD CLAYS.* 
Stuart Weller, Chicago, 111. 
The flora of the Clififwood clays on the south shore of 
Raritan bay,' New Jersey, has been studied in detail by Hol- 
lick and Berry, but no careful study of the fauna of these 
beds has previously been attempted. An investigation of this 
fauna by the author shows its close relationship to the 
faunas of the "clay marl" formations above, but at the same 
time shows that the Cliffwood fauna possesses an individual 
charcater of its own. The geographic distribution of the 
beds containing the fauna is limited to a small area between 
Clififwood point and the head of Cheesquake creek, while the 
superjacent Alerchantville clay, with its uniform fauna, ex- 
tends entirely across the state of New Jersey. The basal 
line of the Merchantville clays can be traced as a natural geo- 
logic horizon across New Jersey, separating the heterogen- 
ous, usually non-marine Raritan beds beneath, from the re- 
markably constant marine beds of the "clay marl" formations 
above. The marine Cliffwood clays represent a limited 
transgression of the marine conditions from the Atlantic 
basin, into the area where non marine sedimentation had 
been in progress during the greater portion of Raritan time. 
These Cliffwood clays are the most notable example of such 
marine sediments in the Raritan, but not the only example, 
smce marine fossils have also been found towards the base 
of the Raritan near Sayresville. In mapping the Clififwood 
clays they should be included in the Raritan rather than with 
the superjacent beds. 
* Abstract of a paper read at the Philadelphia meeting, G. S. A., 
Dec, 1904. 
