682 PROCEEDINGS OF THE BALTIMORE MEETING 



Conrad and Spirifer mesacostalis Hall. Above these succeed typical Chemung 

 sediments containing a Chemung fauna. The percentage of sandstone in- 

 creases in general in ascending in the section. 



In the central part of the area, at an altitude of about 600 feet above the 

 base of the Spirifer disjunctus fauna, appears a zone usually conglomeratic 

 and containing massive sandstones eastward, which bears at places a profuse 

 development of Tropidoleptus carinatus and associated species of Hamilton 

 type. This is in turn succeeded by the Spirifer disjunctus fauna. The Tropi- 

 doleptus carinatus fauna is thus a recurrent fauna of Hamilton type lying 

 within the Chemung fauna of Maryland. The occurrence of this recurrent 

 fauna in the various sections will now be discussed. 



Sections East or Wills Mountain- 

 section 1% MILES SOUTH OF ROUND, WEST VIRGINIA 



This fauna was first observed on the farm of John Will Smith, about 1% 

 miles south of Round, West Virginia. At this point the strata occupy the axis 

 of a syncline and are nearly horizontal. A massive sandstone bearing Gamaro- 

 toechia congregata (Conrad), Spirifer mesacostalis Hall, etcetera, occurs about 

 1,100 feet below the top of the section. Six hundred feet above the latter 

 Spirifer disjunctus was found. This horizon is overlaid by heavy red sand- 

 stone cropping out on the hillsides. The summit of the hill is formed by mas- 

 sive gray sandstones and conglomerate, which bear a profusion of Tropidolep- 

 tus carinatus. The following species were collected at this horizon : 



Tropidoleptus carinatus (Conrad) ab. 

 Spirifer marcyi Hall var. c. 

 Amboccelia umbonata (Conrad). 

 Rhipidomella vanuxemi Hall. 

 Camarotcecliia sappJw Hall. 



Tropidoleptus carinatus is profuse and typical. Spirifer marcyi is a variety 

 with an unusually high area and massive appearance, but admits of no doubt 

 of the identification. All of the species are characteristic of the Hamilton. 



SECTION WEST OF OKONOKO 



A similar conglomerate appears at an altitude of 2,650 feet above the base of 

 the Jennings in the section on the Western Maryland railroad west of Okonoko, 

 north of the Potomac river, on the west side of Green ridge. Spirifer dis- 

 junctus appears in the section at 2,000 feet above the base of the Jennings. 

 The following f aunule was secured at about 2,670 feet : 



Tropidoleptus carinatus (Conrad) 

 Spirifer marcyi Hall 

 Amboccelia umbonata (Conrad) 



SECTION WEST OF PAWPAW 



Numerous excellent exposures occur in the vicinity of Pawpaw. A very 

 massive sandstone, slightly conglomeratic, forms the summit of the Devils 

 Nose. On the west slope of the mountain, along the Baltimore and Ohio rail- 



