A Contribution to the Lower Devonian Faunas of Maryland 11 

 Family AGASSIZOCRINIDAE 



Genus EDRIOCRINUS Hall 



Edriocrinus sacculus Hall 

 Plate XL, Figs. 7-12 



Edriocrinus sacculus Hall, 1859, Pal. N. Y., vol. ill, p. 143, pi. Ixxxvii, figs. 



1-22, 1861. 

 Edriocrinus sacculus Weller, 1903, Geol. Survey N. J., Pal., vol. iii, p. 342, pi. 



xlv, figs. 3-5. 



Description. — " Body more or less obconic or turbinate below and 

 cylindrical above, varying in its proportions of length and breadth. Base 

 varying in form from turbinate to hemispheric, solid, often obliquely 

 truncate or indented below : upper margin marked by six subangularly 

 concave depressions for the insertion of the radial and anal plates. Radial 

 plates large, longer than wide, inserted into the depressions in the margin 

 of the base, gradually expanding towards the upper margin which is 

 thickened externally, slightly concave for the reception of the plates of the 

 arm. Arms broad at the base, composed of numerous very short trans- 

 versely linear plates, of which ten or twelve or more occur below the first 

 bifurcation : first bifurcation in the middle, and each side again bifurcat- 

 ing on the third or fourth plate above, with each division bifurcating once 

 or twice beyond this; making eight or ten or more divisions at the 

 extremities. Anal plates two, the lower large and of the same form as the 

 radial plates; the second one small and short. Proboscis and summit 

 unknown. Column, none; affixed to foreign bodies by the solid base." 

 Hall, 1859. 



This is the most common crinoid of the Oriskany. Usually the arms 

 have been broken off but in the fine collection of Mr. Hartley is a group 

 of two, both of which are nearly perfect, and others preserving fragments 

 of the arms. It was upon collections from Cumberland that Hall based 

 his original description and account of the habits of the genus. 



Occurrence. — Oriskany Formation, Eidgely Member. Cumberland, 

 Knobly Mountain, near Cumberland ; east side jSTicholas Mountain and 

 elsewhere in Maryland ; Franklin, West Virginia. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



