x THE PALEONTOLOGY OF MINNESOTA. 
REVIEW OF EARLIER LITERATURE. 
The great pioneer work on this fauna in America was done by Prof. James Hall.* 
Compared with the recent work by the same author,§ it is at once apparent that great 
improvement has been made in the methods of research, and that remarkable advance has 
been the result of the work of numerous American paleontologists. Prof. Hall, however, 
never returned to a re-examination of the Lower Silurian fauna, as such, but continued to 
develop succeeding faunas of the Paleozoic. While it must be acknowledged that his 
pioneer volume constituted an important epoch in American paleontology, and especially 
in that of the Lower Silurian, it has to be admitted that Lower Silurian fossils have not 
received from him that full elucidation which has marked later his works on the Upper 
Silurian and the Devonian, and on the Carboniferous. Incidentally in his later work he 
has added numerically to the species known from the Trenton and Hudson River forma 
tions, ten being published from the Brachiopoda in vol. vu, part 1; while the morpholog- 
ical values of all the generic names of the Brachiopoda have been reconsidered and fully 
analyzed in the same volume in the light of more recent advanced theories of biological 
paleontology. 
The great labor that has been expended on the paleontology of the region of Cincin- 
nati, where the Lower Silurian strata are at the surface over a large area, extending from 
southeastern Indiana and southwestern Ohio into Kentucky, has consisted very largely of 
the discovery and description of new species. Hall, Meek, Locke, Miller, Dyer, Nichol- 
son, James (father and son), Mickleborough, Ulrich, Wetherby, Byrnes and others have 
added largely to the known fauna of these strata and have carried westward the definite 
stratigraphic limitations of these formations which were established in New York. From 
this region these fossiliferous strata pass out of sight with a westward and northwestward 
dip, rising again in Wisconsin and Minnesota on approaching the confines of the ancient 
land area now characterized by the older formations. 
While all the American literature of the subject, and most of the European, has been 
at hand, and constantly consulted in the study represented by this volume, it has been 
thought desirable to note here more carefully only those geological works which appertain 
to the valley of the Mississippi, including Minnesota and the states adjoining, viz.: 
Wisconsin, lowa and the northwestern portion of Illinois,t and the contiguous portions 
of Manitoba. These synoptical notes are arranged in chronological order. 
*Palwontology of New York, vol. 1, 1847. It shouid not be forgotten, however, that Mr. T. A. Conrad, between 1838 and 
1843, studied the paleontology of New York assiduously and described many Lower Silurian forms, 
§Palawontology of New York, vol. v1i1, 1892. 
t+In the Tenth Annual Report of the Geological Survey of Indiana the reader will find a bibliography, by Mr. 8, 
A. Miller, of the paleontology of the Cincinnati region up to the year 1879, 
