Maryland Geological Survey 165 



since one supplements the other. These exposures are termed the Upper 

 and Lower quarry zones respectively. 



The Upper quarry zone is the site of an old limestone quarry on the 

 south side of the National Eoad, 310 feet west of the middle of the bridge 

 over Tonoloway Creek. At the top of the section in heavy-bedded lime- 

 stone Oypidula coeymanensis var. prognostica occurs. At the base of the 

 section in this quarry is a massive 3^-foot bed of stromatoporoids contain- 

 ing corals. The remainder of the section is concealed at this locality, but 

 by following the strike of the rock northeast across Tonoloway Creek, one 

 finds the Stromatopora bed on the hillside northeast of the road leading 

 north from Hancock, about 59 feet north of the fork in the road. The 

 limestone beneath the Stromatopora bed is quarried at this point for the 

 burning of lime. The section beneath the Stromatopora bed is called the 

 Lower quarry zone. 



This section was formerly considered Coeymans and the Lower Keyser 

 was thought to consist of the thin-bedded limestones with abundant 

 ostracods found beneath the strata quarried. Careful search was made 

 for fossils below the described section in the thin-bedded limestones of 

 the Tonoloway, but none other than Tonoloway forms were found. The 

 Stromatopora bed occurs in the lower part of the Keyser. 



The following section begins at the top of the exposure in the old 

 abandoned quarry on the National Eoad, 310 feet west of the middle of 

 the bridge over Tonoloway Creek. 



Helderberg FVjrmation 



Horizontal Vertical Total 

 Keyser Member distance thicliness vertical 



feet feet thicliness 



Heavy-bedded gray-blue arenaceous limestone con- 

 taining a form of Gypidula (cf.) coeymanensis var. 

 prognostica. At the bottom of this unit the following 

 fossils were obtained: Ortlioceras sp., Spirifer mo- 

 destus (aa), Atrypa reticularis (c), Chonetes jersey- 

 ensis (a), StenocMsma sp., Strophcodonta sp 166.2 5.2 104.2 



Dark blue thin-bedded nodular limestone weathering 

 gray. At the bottom of this unit were found Chonetes 

 jerseycnsis (a), C. jerseyensis var. spinosa (r), Steno- 

 chisma sp., Dalmanella SV; Rhynchospira sp 158.2 8.6 99.0 



Dark grayish-blue, thin-bedded nodular limestone 

 weathering gray. At the bottom occur Camarot^jechia 

 litrhfieldensis (c), Atrypa sp., Favosites s'p.,hryozoa.. 145.2 4.6 90.4 



