Maryland Geological Survey 155 



Helderberg Formatiox 



Vertical Total 

 Keyser Member thickness vertical 



feet thickness 



Gypidula coeymanensis var. prognostica Is found throughout 

 this unit and at the bottom occur Spirifer octocostatus (r), 

 Atrypa reticularis (c), Dalmanella cf. concinna (r), Meristella 

 sp., Camarotachia litchfieldensis (c), StenocMsma deckerensis 

 (c), Gypidula coeymanensis var. prognostica zone 4.6 120.6 



Dark blue limestone, thin-bedded at the top, becoming massive 

 near the middle and containing near the bottom a Stromatopora 

 bed. Shaly and thin-bedded limestone at the bottom. Fossils 

 rare 42.8 116.0 



Concealed between quarries. This interval is formed of 

 shaly limestone 24.9 73.2 



Thin-bedded dark blue limestone with some heavy nodular 

 beds weathering to a gray-blue color, containing a great abund- 

 ance of fossils. At the top Balostomella interporosa (a), Atrypa 

 reticularis (aa), Orthoceras sp., Aulopora schueherti, Aulopora 

 schohariw, Camarotvchia litchfieldensis (c), Stenochisma decke- 

 rensis (c) Stenochisma formosa (c), Uncinulus convexorus (c). 

 At the bottom occur Camarotachia litchfieldensis (c), Stropheo- 

 donta varistriata ( r) 18.5 48.3 



Dark blue limestone, thin-bedded toward the top, heavy- 

 bedded at the bottom 19.9 29.8 



Heavy-bedded dark blue limestone, containing at the bottom 

 Leperditia sp., Stenochisma sp 9.9 9.9 



Thickness of Keyser member described 120.6 



ToNOLowAY Formation 

 Thin-bedded dark blue limestone breaking with a clean frac- 

 ture 19.9 



East wall of quarry. 



The following fossils, whose exact horizon is not known, were collected 

 in the Keyser beds at Hyndman, Pennsylvania, and are now in the U. S. 

 National Museum : Cyathophyllum schiicherii, Favosites helderbergice 

 var. prcecedens, SchucherteJla decl-erensis, Chonetes jersey ensis, Whit- 

 fieldella cf. nucleolata. 



XL Section at Market Street Bridge, Cumberland 

 This section is located south of Shriver Eidge at the south end of the 

 Market Street Bridge in the city of Cumberland. It extends along the 

 soutli side of the Iluntinirton Division of the Pennsylvania Eailroad, and 



