Maryland Geological Survey 175 



member have already been described. Tlie following section of the Coey- 

 mans and New Scotland is exposed at this place : ^ 



Oriskany Formation 



Vertical Total 



Shriver Chert Member thickness vertical 



feet thickness 



Siliceous shale containing chert nodules. 



Helderbero Formation 

 New Scotland Member 



Fissile drab shale 20.0 54.2 



Shale with several chert layers 1.5 34.2 



Gray crystalline limestone with interbedded white chert. 

 The chert is in 6-inch layers and makes up nearly the entire 

 thickness of the unit. Leptana rhomboidaUs occurs through- 

 out the unit: Stropheodonta planulata and Schicehertella wool- 

 worthana (a), 11; Stroplwnella undaplicata, 5; Spirifer macro- 

 pleurus, 6.5; 8. pcrlamellosus and S. macropleurus, 4.5; Eri- 

 dotrypa corticosa, Fenestella idalia. Polypora compacta, Ortho- 

 pora regularis, Stictopora ? papulosa, Orthopora rhombifera, 



3.0 ; Spirifer macropleurus, 1.8 11.5 32.7 



Medium-bedded crystalline limestone with several chert 

 layers. Leptwna rhomboidaUs, Dalmanella perelegans and 

 Schuchertella woolworthana occur throughout the unit; Ano- 

 plotheca concava is abundant at the top and the base; Stropheo- 

 donta planulata, Spirifer cyclopterus. Strophonella leaven- 

 worthana, 2.5; Schuchertella woolworthana var. with fine strias 

 Proetus cf. protuberans. Stropheodonta planulata, Meristella 



arcuata, Rhynchospira globosa at base 3.5 21.2 



Medium-bedded, crystalline limestone with but little chert. 

 Lepta-na rhomboidaUs occurs throughout; Dalmanites pleu- 

 roptyx and Rhipidomella oblata, 6; Schuchertella woolworthana, 



Spirifer cyclopterus 4; Anoplotheca concava 3 (a) >. . 7.5 17.7 



Shale. Anoplotheca concava (a) smd Spirifer cyclopterus .. . 1.0 10.2 



Thickness of New Scotland member 45.0 



Coeymans Member 



Dark blue crystalline limestone, very massive and very fos- 



siliferous. Lower surface of unit somewhat irregular. At top 



occur Schuchertella woolworthana with fine striae; Actinopteria 



communis (?), Spirifer cyclopterus, Gypidula coeymanensis, 



^ Measured by C. K. Swartz and assistants. The figures following the names 

 of the fossils indicate the altitude in feet at which they occur above the base 

 of the units. 



