January, 1900. Teller— The Hamilton Formation. 
55 
organic contents have been studied. Criticism by future writers on 
the subject is to be expected and is desired, as it is only by such 
criticism that a perfect knowledge of the formation at the locality 
can be secured. 
The Crinoids and Blastoids of the locality have been described 
and figured by Mr. Stuart Weller, of the University of Chicago, 
while the fish remains, of which no less than sixteen species have 
been recognized, have been identified or described and illustrated 
in three separate articles by Dr. C R. Eastman, of the Cambridge 
Museum of Comparative Zoology, and who still has many of the 
best specimens for further study and description in future publi- 
cations. 
Since the publication of the list of the fauna of the locality 
a few new and interesting forms have been discovered. 
The thanks of the writer are due to the late Thomas A. Greene, 
also to Mr. F. L. Horniffer and Chas. E. Monroe, local collectors, 
for speciiriens and several of the observations presented herein. 
For the illustrations and descriptions of the types described 
from the locality, and of many of the species there found, the 
reader is referred to the works cited in the bibliography herewith. 
Bibliogfraphy of the Hamilton Formation of "Wisconsin. 
Buckley, E. R. — Wisconsin Geological and Natural History 
Survey, Bulletin No. IV. Economic series No. 2, 1898; pages 
85 and 298. 
Chamberlain, T. C. — Devonian. Hamilton Cement Rock, in 
Geology of Wisconsin, Vol. H., 1878, pp. 395-405. 
. — Devonian Age, or Age of Fishes ; in Geology of 
Wisconsin, Vol. I., 1883, chapter X., pp. 201-212. 
Eastman, C. R. — On the relation of certain plates in the 
Dinichthyids, with descriptions of new species. Bulletin of the 
Museum of Comparative Zoology, Vol. XXXI., 1897. 
. — Dentition of Devonian Ptyctodontidac. The 
American Naturalist, Vol. XXXII., No. 379, 1898; pp. 473-478. 
. — Dentition of Devonian Ptyctodontidac. The 
American Naturalist, Vol. XXXII., No. 380, 1898 ; pp. 545-560. 
. — Some New Points in Dinichthyid Osteologv. The 
American Naturalist, Vol. XXXII., No. 382, 1898 ; pp. 747-768. 
Hall, James. — Report of Progress Geological Survey of Wis- 
consin, 1861. Published as Document 15, with Governor's Mess- 
age, 1 86 1. 
. — Report of the Geological Survey of the State of 
Wisconsin, Vol. i, 1862. 
. — Descriptions of the Gastropoda, Pteropoda and 
Cephalopoda, of the Upper Helderberg, Hamilton, Portage and 
