108 The Lower Devonian Deposits of Maeyland 



Vertical Total vertical 

 thickness thickness 



ft. in. ft. in. 



Concealed. Chiefly shale. 

 Spring. 



Massive, gray, crinoidal limestone 9 1 232 7 



Interbedded shale and limestone 4 4 223 6 



Massive, fossiliferous limestone containing chert 3 9 219 2 



Thin-bedded banded limestone 5 10 215 5 



Shaly limestone 7 10 209 7 



Medium-bedded gray limestone 8 9 193 



Thin-bedded shaly limestone 13 184 2 



Shale 1 171 2 



Massive dark limestone, thinner beds near top 21 10 170 2 



Calcareous shale with thin beds of impure limestone 2 148 4 



Massive dark blue limestone 7 4 146 4 



Shale and shaly limestone interbedded with bands of 



purer limestone 26 10 131 



Massive gray-blue banded limestone 11 7 112 2 



Nodular limestone, shaly at bottom 11 5 100 7 



Massive nodular limestone 11 11 89 2 



Thin-bedded, nodular limestone 3 9 77 3 



Gray nodular limestone, some thin beds 13 6 73 6 



Stromatopora reef, upper 2 feet consisting of smaller 



species 12 60 



135 mile post. 



Thin-bedded, nodular limestone 5 11 48 



Gray, impure limestone, somewhat crinoidal 10 42 1 



Nodular limestone, somewhat shaly 24 6 41 3 



Massive dark blue limestone, upper 18 inches thinner 



bedded 16 16 9 



Thin-bedded, argillaceous limestone, lowest stratum ex- 

 posed, probably base of Keyser limestone 9 9 



Concealed. Fissile, platy limestone is exposed north of 

 this point, containing numerous ostracods. 



The most important feature of the section is the marked lithological and 

 faiinal change at the base of the Keyser. The underlying beds are fissile, 

 platy limestones with an ostraeod fauna, contrasting greatly with the 

 lower nodular beds of the Keyser. The Chonetes jerseyensis fauna is 

 present in the lower beds. Rhijnchospira glohosa is abundant near the 

 base of the section and is succeeded by a StromatopoTa reef. Cladopora 

 rectilineata and Halysites catemdatus are also abundant in the lower 

 strata of the same age at Grovania while Tcnfaculites gyracantlms occurs 



