328 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Cladoporasv. F,et Meters 



Romingeria sp. 



Atrypa reticularis (Linn.) 

 The line between the light gray limestones of the 

 Pipestone formation and the dark lead-gray of the 

 Messines formation is strongly marked and can be 

 recognized miles away by the contrast in color ; the 

 two formations also give rise to different topographic 

 forms, as the upper division breaks down more readily 

 into terraces and low cliffs when the dip is nearly 

 horizontal, while the lower division forms dark cliffs 

 with a steep dip ; the upper division forms sharp high 

 points or ridges, and the lower division a more or less 

 broken cliff, capping the light gray pre-Devonian beds 

 beneath. 



Messines Formation (Middle Devonian) 

 I. Section measured from top downward. 



Strike N. & S., Dip W. 

 la. Dark arenaceous, more or less bituminous limestone in 

 beds breaking down in layers 3 to 6 inches (8 to 



15 cm.) thick ' 45 13.7 



i&. Gray and buff-weathering, shaly gray limestone 30 9.1 



ic. Purplish, finely arenaceous shale, with thin layers of 



limestone 24 7.3 



id. Thick-bedded, dark arenaceous limestone no 33.5 



le. Dull lead-gray, finely arenaceous limestone, with corals 



and Stromatopora very abundant 184 56.1 



l/. Similar to id, with Stromatopora bed, 20 feet (6.1 m.) 



thick, 35 feet (10.7 m.) from base 270 82.3 



Fauna. — At from 100 to 105 feet (30 to 32 m.) from the 

 base of if, fossils are abundant. Dr. Kirk con- 

 siders them to indicate the Middle Devonian (Jefferson 

 limestone) : 



Stromatopora sp. 

 Crinoid columns 

 Gomphoceras sp. 

 Palaeoneilo sp. 

 Atrypa reticularis (Linn.) 

 Stropheodonta sp. 



Total of 1 663 



The Devonian terminates at its base in thin-bedded, 

 dark dirty-gray layers ; at 25 to 30 feet {7.6 to 9.1 m.) 

 from the base, a band of bluish-black, compact lime- 

 stone is quite fossiliferous as well as the shaly part- 

 ings between the layers. 



Fauna. — . 



Diaphorostoma sp. 



Palaeoneilo sp. 



Atrypa reticularis (Linn.) 



Gomphoceras sp. 



