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. vm, 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, Iowa and the northwestern portion of Illinois,! and the contiguous portions 

 of Manitoba. These synoptical notes are arranged in chronological order. 



Palaeontology of New York, vol. I, 1847. It should 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. 



Palaeontology of New York, vol. vm, 1892. 



tin the Tenth Annual Report of the Geological Survey of Indiana the reader will find a bibliography, by Mr. S. 

 A. Miller, of the paleontology of the Cincinnati region up to the year 1879. 



