ABSTRACTS AND DISCUSSIONS OF PAPERS 8.9 



SILURIAN SYSTEM OF MARYLAND i 

 BY C. K. SWARTZ AND W. F. PROUTY 



(Abstract) 



The authors have been engaged in the study of the Silurian system of Mary- 

 land for several years and this paper presented a synopsis of their chief 

 results. 



The various formations that constitute the Silurian system of Maryland 

 were discussed, including their lithology, faunas, and stratigraphic features. 

 The formations were correlated with those of the same age in New York and 

 other parts of the Appalachian basin. The problem presented by the Silurian 

 Red Beds was considered briefly and certain analogies between them and the 

 Catskill formation were pointed out. 



Presented in abstract extemporaneously by the senior author. 



Discussion 



Mr. G. W. Stose : The stratigraphy presented by Mr. Swartz in the diagrams 

 is no doubt more accurate and final than that in my report on the eastern 

 part of the area about Hancock, Maryland. The interfingering of red sedi- 

 ments toward the east, extending to lower horizons than the base of the Wills 

 Creek, is of special interest and will require careful study before final con- 

 clusions of nomenclature and correlation are reached. 



In regard to the faunal relations of the Kiefer sandstone, I do not feel com- 

 petent to speak ; but Mr. Ulrich, who was responsible for having it made a 

 member of the McKenzie formation in my report, has, in a recent table, placed 

 it as a member of the Clinton formation, thus agreeing with Mr. Swartz. 



Mr. George H. Chadwick : Objection is made to the inclusion of the Roches- 

 ter in the Clinton. The distinctive Rochester fauna is widespread and the 

 facts presented in this paper emphasize the undesirability of submerging it in 

 the very different assemblage lying beneath it, against the plain evidence that 

 the Rochester fauna endures with little modification into the Lockport. 



HOMOGLINE AND MONOCLINE 



BY REGINALD A. DAI.Y 



CONTENTS 



Page 



Definition of "homocline" 89 



Different definitions of "monocline" 90 



Favored definition of "monocline" 91 



Summary 92 



Definition of "Homocline" 



Workers in deformed strata have long felt the need of a general name for 

 a mass of bedded rocks all of which dip in the same direction. Such a mass 

 may be a tilted fault-block, a series of tilted fault-blocks, a combination of 



1 Presented by permission of the Director of the Indiana Geological Survey. 



