150 The Lower Devonian Deposits of Maryland 



Vertical Total 

 thickness vertical 



feet thickness 



Thin-bedded gray limestone in seven beds separated by shaly 



layers 4.0 170.5 



Thin-bedded, somewhat nodular gray limestone; shale part- 

 ing at top 6.0 166.5 



Massive blue limestone. Schuchertella deckerensis occurs 



at base 3.7 160.5 



Nodular, thin-bedded limestone 0.5 156.8 



Single bed of gray limestone i. . . . 0.8 156.3 



Thin-bedded, somewhat nodular, argillaceous gray limestone. 

 Layers of dark chert in upper half of unit. Dalmanella con- 

 cinna is abundant throughout. Striatopora sp. 148, Schucher- 

 tella deckerensis 140, 148, 149, 153.5, Atrypa reticularis 148, 



153, Chonetes jerseyensis 142.8, 147, 153, Stenochisma decke- 

 rensis 140, 140.8, 148, 153, PhoUdops ovata 140, Camarotwchia 

 litchfieldensis 139.5, 142, LepUrna rhomboidalis 140.8, Spirifer 

 octocostatus 139.5, Platyceras sp. 147, 153, Calymene camerata 



154, Klwdenella turgida 143, 153.5, Batostomella interporosa 143, 

 153.5, Stromatotrypa glohularis 153.5, Fistuliporella mary- 

 landica 140, 143, 153.5, Orthopora rhombifera 140, 143, 153.5 

 Fenestella (Cycloporina) altidorsata 140, 143, Thamniscus regu- 

 laris 143, Polypora dictyota 140, 143, Fistuliporella maynardi 

 143, Eridotrypa parvulipora 140, Rhophalonaria attenuata 140, 



crinoid rings 16.0 155.5 



Massive, nodular gray limestone. Atrypa reticularis and 

 Gypidula coeymanensis var. prognostlca are abundant through- 

 out. Dalmanella concinna 137.4, 139, Orthoceras sp., Calymene 

 camerata. Stenochisma deckerensis. Fenestella (Cycloporina) 

 altidorsata 137.4, Schuchertella deckerensis, 137, crinoid rings. . 2.5 139.5 



Massive dark blue limestone. Gypidula coeymanensis var. 

 prognostica abundant throughout. At bottom of this unit occur 

 Chonetes jerseyensis, Dalmanella concinna. Merista typa, Ca- 

 marotirchia litchfieldensis (a), Spirifer octocostatus, S. va- 

 nuxemi var. Strophonella geniculata, Schuchertella deformis, 



and bryozoa 7.0 137.0 



Massive blue, somewhat nodular limestone 18.2 130.0 



Thin-bedded, bluish-gray, somewhat argillaceous limestone. 

 Contains Dalmanella concinna (a), Spirifer m,odestus (a), 



Stenochisma formosa 28.0 112.0 



Schuchert reports Camarocrinus stellatus from this unit. 

 Massive nodular limestone with crinoid fragments. At the 

 base occur Lepadocrinus stems, Cladopora rectilineata, Atrypa 

 reticularis, Schuchertella deckerensis, Camarotoschia sp., Stro- 

 pheodonta sp., Fenestella cumberlandica, Cyphotrypa rotundata, 

 Batostomella interporosa, Orthopora rhombifera 5.0 84.0 



