144 The Lower Devoniax Deposits or Maryland 



thick is exposed on the ea?t face of the quarry. Only a few feet of what is 

 thought to be the middle Keyser is exposed here. The upper part of the 

 section is in the Rensselceria mutabilis suhzone. 



The section begins at the top of the exposure in the quarry and only 

 the vertical thickness was measured. 



Helderberg Formation 



Vertical Total 



Keyser Member ^i"^^-- -^^ioai^ 



Massive hard, cherty gray limestone. Throughout this bed 



the following fossils were found: Favosites helderbergice prw- 



cedens (aa), Cladopora rectilineata (r), Stromatoporoids (aa), 



crinoids (aa) ,Renssela:ria mutaMlis {aa.) ,8tenocMsma formosa 



{aa), Bryozoa (aa) 15.0 31.9 



Massive blue limestone. At the bottom occur Favosites hel- 

 derbergice var. prwcedens (a), crinoids (a), Batostomella inter- 

 porosa. Eridotrypa parvulipora, Fistuliporella marylandica, Or- 



thopora rhombifera 11.3 16.9 



Gray limestone made up almost entirely of crinoids and Bryo- 

 zoa. Atrypa reticularis (c) 1.6 5.6 



Light blue limestone. At hottom occur Atrypa reticularis {r) 4.0 4.0 



Concealed 



Thickness of Keyser member exposed 31.9 



VII. Section in Cash Valley 



The Keyser is exposed about 3-1 miles southwest of Corriganville on 

 the same ridge upon which the Helderberg formation is seen at the Devil's 

 Backbone. A branch of Braddock Eun has cut across the ridge at this 

 point and the quarrying of limestone for the burning of lime has exposed 

 part of the Keyser. 



The sequence of strata seems to be identical with that at the Devil's 

 Backbone. Tlie thick, heavy crinoid bed of the lower Keyser is exposed 

 near the bottom of the section. The Gypidula cceymanensis var. prog- 

 nostica zone occurs perhaps a little higher up in the section than at Devil's 

 Backbone and only about 2 feet of this zone is exposed. Beneath the 

 Gypidula zone Dalmanella clarhi is very abundant and has not been found 

 in any other section. It is associated with Spirifer vanuxemi, 8. modestus, 

 and Chonetes jerseyensis. Halysites catenulatus is found in the lower 

 third of the Keyser member as at Devil's Backbone and accords with its 



