PREFACE 



The present volume is the sixth of a series of reports dealing with the 

 systematic geology and paleontology of Maryland, the Lower Devonian, 

 Lower Cretaceous, Eocene, Miocene, and Pliocene and Pleistocene de- 

 posits having already been fully described. 



The present volume is devoted to a consideration of the Middle and 

 Upper Devonian deposits and their contained faunas, the Lower Devonian 

 geology and its life having been fully treated in a companion volume 

 devoted to that subject. 



The discussion of the Middle and Upper Devonian is the combined 

 result of the work of a nundjer of individuals, many of them experts in 

 special fields of research. 



The general stratigraphic description of the Middle and Upper De- 

 vonian has been the work of Prof. Charles S. Prosser, of Ohio State Uni- 

 versity, who has also contributed the discussion of the faunas of the Middle 

 Devonian. 



The Upper Devonian faunas are described by Dr. John M. Clarke, 

 Director of Few York Geological Survey, and Dr. Charles K. Swartz, 

 of the Johns Hopkins University. Dr. Edward M. Kindle, formerly of 

 the U. S. Geological Survey, has contributed a chapter on the stratigraphy 

 and fauna of the Onondaga horizon of the Middle Devonian. 



The limited Brj'ozoan and Ostracod faunas are contributed, as in 

 previous volumes, by Drs. E. 0. Ulrich and E. S. Bassler, of the U. S. 

 Geological Survey and U. S. J^ational Museum respectively. 



Dr. C. K. Swartz, of the Johns Hopkins University, has furnished a 

 chapter on the correlation of the Onondaga and Marcellus members of 

 the Eomney formation, and has contributed a large amount of material 

 for the stratigraphic and paleontologic chapters. 



