INTRODUCTION 
1 1 
Late Niagaran (Brownstort) ; Tennessee 
By Charles Wachsmiith, 1885 to 1888. W. F. Pate, 1906, 1907. Braun, 
191 1. 
From Col. S. S. Lyon, collection, 1859 to i860. Mrs. J. M. IMilligan, collec- 
tion; Jacksonville, Blinois. Pate, collection; before 1906. 
Other Collections Studied 
American Museum Natural Flistory, New York, Flail Collection; Lockport. 
State Museum, New York, Albany, Hall and Jewett collections; Lockport and 
Waldron. Sir Edmund Walker, Toronto; Grimsby, Ontario. Walker Museum, 
University of Chicago; Chicago area and St. Paul. University of Illinois, Cham- 
paign; Worthen collection. Vanderbilt University, Nashville; Safford collec- 
tion. United States National Museum; Containing Troost collection, Tennes- 
see; Rominger collection, Tennessee and Michigan; Mr. Ulrich’s collection of 
Ordovician from Minnesota. 
British Museum; London. Dudley Museum; Dudley, England. 
All of these last mentioned collections were most generously placed at my 
disposal for study, for which I am deeply indebted to the owners and authorities 
in charge of them. 
I am also under renewed obligation to Hon. Charles D. Walcott, Secretary 
of the Smithsonian Institution; to Dr. Geo. P. Merrill, head of the Division of 
Geology in the National Museum, for their continued interest in my researches; 
to Dr. R. S. Bassler, Curator of Paleontology, for his unflagging assistance 
during their prosecution ; and to Miss iMargaret W. Moodey, Registrar in the 
Division of Geology, who has direct charge of my collection and library, and 
has administered my office in the National Museum during my protracted dis- 
ability, when I was endeavoring to complete the later stages of this work through 
the medium of correspondence. This involved numerous commissions in the 
way of selecting and sending specimens, hooks and notes, looking up references, 
and attending to the endless details incident to such investigations. All of these 
were executed by her, under advice of Dr. Bassler when needed, with a zeal and 
intelligent interest that met, and often anticipated, every recjuirement. 
The drawings for the plates have been in the course of execution during 
a period of more than fifteen years, by Mr. Kenneth M. Chapman, of Santa Fe, 
New Mexico, the artist of many of my former works. They are based upon 
photographs made by himself at first, and in the later stages by Dr. Bassler and 
Dr. C. E. Resser. To his keen observation I owe their accuracy of details, and 
as works of art the drawings speak for themselves. 
Except as otherwise stated, the originals of all the drawings, including the 
types of the new species herein described, are in the author’s collection in the 
United States National IMuseum. 
