4 
BULLETIN 108, UNITED STATES NATIONAL MUSEUM. 
stratigraphy of that State. Dr. Eugene A. Smith, the first to decipher the correct 
sequence of lower Tertiary formations in the Southern States, supplied important 
collections from Alabama, particularly from the Midwayan group. 
Ample collections of washings with bryozoa from the typical Jacksonian of 
Mississippi were secured by Mr. E. N. Lowe, State geologist, who has been ever 
ready to obtain material to advance these studies. The lower Jacksonian fauna 
herein described is largely the result of Mr. Lowe’s efforts. Mr. John M. Nickles 
also has contributed specimens for study, particularly from the Midwayan of 
Arkansas. 
The Ulrich collection, now the property of the United States National Museum, 
has furnished some excellent materials of great use in the present monograph. The 
authors have also had the advantage of the advice and experience of Dr. E. O. 
Ulrich, who made these particular collections in the hope that some day the subject 
would be monographically treated. 
Professor H. Douville, member of the Institute of France, has verified our classi- 
fication, and he has been most generous to the senior author with his advice and en- 
couragement. We are sincerely thankful for his help. 
The authors are deeply grateful to the National Academy of Sciences for 
financial assistance which made it possible for them to prepare and include in this 
monograph the important portion relating to the Cvclostomata, thereby completing 
the study of the North American early Tertiary species. 
OBJECTS AND METHODS OF STUDY. 
There are many minute openings and almost imperceptible protuberances on 
a fossil bryozoan. Their enumeration, the description of their form, size, and 
position would be a work both tedious and perfectly useless, unless, by the aid 
of zoology, a reason for their presence can be obtained. Here, more than anywhere 
else, the intimate union of zoology Avith paleontology is absolutely necessary. 
The fossil bryozoa are more than small perforated stones. They are the' 
remains of creatures of a former time, and the object of the paleontologist should 
be their resurrection. His role is to animate them in order to classify them, and 
to classify them correctly in order to use them. 
This fertile method of constant comparison with the living specimens is tending 
to prevail in Europe, but here in America circumstances, notably the predominance 
of the Paleozoic faunas, have not permitted its application in brvozoology. The 
present authors have endeavored to inaugurate this method of research in America 
by a study of the exuberant faunas of the great American Tertiary Gulf. They 
have endeavored to describe these faunas so as to be understood by all naturalists 
and not by the specialist alone. 
The lack of large monographs upon bryozoology causes the study of the fossil 
forms to be exceptionally difficult. The most recent monograph, that of Hincks, 
dates from 1880 , and is concerned only with Great Britain. Since that time, it is 
true, important researches have been made by many eminent naturalists of all 
countries and published in a great number of scientific works, in all languages. 
All these works are assembled only in the libraries of the very few specialists who 
