BRACHIOPODA. 225 



0. discus, Hali, Lower Helderberg. 



* 0. eminens, Hall Lower Helderberg. 



* 0. oblata, Hall Lower Helderberg. 



* 0. tubulostriata, Hall Lower Helderberg. 



* 0. Cumberlaudia, Hall Orinkany. 



* 0. musculosa, Hall Oriskany. 



* 0. alsus, Hall Schoharie. 



* 0. peloris, Hall Schoharie. 



* 0. Cleobis, Hall Corniferous. 



* 0. Livia, Billings Corniferous. 



0. Semele, Hall Corniferous. 



* 0. Vanuxemi, Hall Hamilton. 



*^- ^^"l^^^^L Hereick Waverly.t 



* 0. cyclas, Hall Hamilton. 



* 0. idonea, Hall Hamilton. 



* 0. Leucosia, Hall Hamilton. 



* 0. Penelope, Hall Hamilton. 



* 0. solitaria, Hall Hamilton. 



* 0. suborbicularis, Hall Hamilton. 



* 0. Pennsylvanica, Simpson Chemung. 



[?] 0. cuneata, Owen Devonian. 



0. Lucia, Billings Devonian. 



O. occasus. Hall Waverly. 



0. subelliptica, White and Whitfield Waverly. 



* Missouriensis, Swallow Choteau. 



* 0. Burlingtonensis, Hall Burlington. 



0. Dalyana, Miller ?Burlington. 



* 0. Thiemii, White Burlington. 



0. Clarkensis, Swallow Keokuk. 



* 0. Oweni, sp. nov Knobstone.| 



* 0. dubia. Hall St. Louis. 



t There is a larg-er form of Obthis in the Waverly of Ohio, which has a very gibbous brachial valve, 

 and can not be regarded as identical with this variety of 0. Vanuxemi. 



X The "Knobstone group" of Oweic, in Kentucky and the southern part of Indiana, in its lowest mem- 

 bers, has been generally regarded .as of the age of the Waverly of Ohio. Its upper member has been 

 paralleled with the Keokuk, but the limitation between these formations is not always well defined or easily 

 determined. 



