50 Introduction 



as transitional, and the Devonian composed of the Eomney shale, and the 

 Jennings and Hampshire formations. 



In 1897 the first volume of the Maryland Geological Survey appeared 

 in which Prof. Clark described the Maryland formations and gave first 

 the name adopted by the U. S. Geological Survey, for its Virginia and 

 West Virginia folios, followed in parenthesis, by the name of the equiva- 

 lent New York stage or series. On the geological map the rocks now re- 

 ferred to the Devonian are represented by four different colors with the 

 following explanation : Lewistown (L. Helderberg-Niagara) , Monterey 

 (Oriskany), Jennings-Eomney (Chemung-Hamilton), and Hampshire 

 (Catskill). Later and more complete investigations have shown that in 

 all essential characters the majority of the Paleozoic formations of Mary- 

 land agree with those of New York and Pennsylvania. 



Prof. Charles Schuchert published a paper in 1900 on the "Lower 

 Devonic aspect of the Lower Helderberg and Oriskany formations " 

 which contains a section of the Helderberg limestone and Oriskany sand- 

 stone as shown at the " Devil's Backbone " on the Baltimore and Ohio 

 Eailroad to the northwest of Cumberland. In a subsequent paper he 

 changed to some extent his identification of the subdivisions of the Helder- 

 berg limestones bringing them more nearly in harmony with the results 

 obtained by Dr. Eowe and the writer. The former paper gave an extended 

 review and discussion of the Lower Devonian of Europe and America. 



The same year Dr. John M. Clarke again reviewed the evidence regard- 

 ing " The Devonic age of the Helderbergian fauna and the base of the 

 Devonic System in New York " and considered the arguments " from 

 correlation," " from the intrinsic character of the fauna," and " from 

 stratigraphy." In this review Dr. Clarke stated that " the strongest 

 demonstration of its Devonic affinities is intrinsic " and derived from the 

 study of the New York Helderberg fauna. 



In 1900 " The Geology of Allegany County," by Dr. C. C. O'Harra, 

 was published in the Allegany County report. It contains a full de- 

 scription of the formations of Allegany County together with an account 

 of their stratigraphy, areal distribution, and of the character and origin 

 of their sediments. The Devonian is given as composed of the Helderberg 



