Charles DB. and Mary Waux MalcottiWesearch Fund 
CHAZYAN AND RELATED BRACHIOPODS: 
PARAL) ly Rel 
By G. ARTHUR COOPER 
Curator of Invertebrate Paleontology and Paleobotany 
United States National Museum 
(WirTH 269 PLates In Part IT) 
Section I. THE FORMATIONS 
INTRODUCTION AND STRATIGRAPHIC SETTING 
The brachiopods forming the subject of this monograph are a natural sequel to 
those of the Ozarkian and Canadian periods. While Dr. E. O. Ulrich and I were 
preparing the monograph on Ozarkian and Canadian brachiopods it became evi- 
dent that post-Canadian brachiopods were as little known as those on which we 
were working. It was, therefore, planned to prepare a second monograph under 
the joint authorship of Ulrich and myself on the brachiopods of Ulrich’s Chazyan 
which included all the rocks between the top of the Canadian and the Lowyville. 
Ulrich’s division comprised a very imposing sequence of rocks in the Appala- 
chians and many other parts of North America. To his Chazyan was added the 
Black River group of rocks and its correlates as Ulrich understood this group. 
The brachiopods from the Black River were clearly closely related to those of 
the Chazyan and, like the Chazyan, were little known. The plan was to regard 
the lower Trenton, as understood by Ulrich, as the upper limit for the study. 
Many unforeseen circumstances transpired to delay the work, and in the mean- 
time Dr. Ulrich’s health declined to such an extent that he withdrew from the 
project. 
While the studies were progressing and the collections were being brought 
together, views were changing on the stratigraphy of the Chazyan and Black 
River divisions. G. M. Kay, in New York and Ontario, was revising the Tren- 
ton and elaborating the Rockland division which proved to be of wide distribu- 
tion. At the same time, Byron N. Cooper, then of the Virginia Geological Sur- 
vey, and C. E. Prouty, of the Tennessee Valley Authority, were establishing in 
Tazewell County, Va., a detailed section that was to become a standard for the 
area. These studies and my own investigations in the Appalachians showed 
clearly that the Chazyan of Ulrich actually included rocks from Chazyan to Tren- 
ton and that the Black River of Ulrich was in large part of Trenton age. In 
spite of these disclosures it seems unnecessary to change the name of this mono- 
graph. The formations now have a far different alignment from that which UI- 
SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 127, PART I 
