680 Systematic Paleoxtology — Upper Devonian 



ton Eowe, a graduate of the John Hopkins University and an assistant 

 on the Geological Survey of Maryland ; by him much valuable material 

 employed in the study of the Jennings fonuation was collected. 



Occurrence.- — Jennings Formation, Chemung Member. Williams 

 Eoad, Polish Mountain. Parkhead Member. Eocky Eun cf., Town 

 Creek, 1863 cf., 2i/2 miles above mouth of Sideling Hill Creek, cf. 



HOLOPEA MARYLANDICA D. Sp. 



Plate LXIX, Figs. 19, 20 



Description. — Shell short, rotund, spire short consisting of 4-5 volu- 

 tions, body whorl projecting well beyond the rest of the spire, but not so 

 extremely ventricose as in many of these species. Whorls all convex and 

 smooth, the upper whorls having an obliquely sloping surface and the 

 body whorl having a vertical width equal to the remaining height of the 

 spire. Sutures deep but not excavate. No concentric surface lines are 

 retained on the external casts. Height of an average specimen 15 mm.; 

 diameter of body whorl 18 mm. 



This species is distinguished from its associate H. rowoi by its lower 

 spire and proportionally broader body whorl. 



Occurrence. — Jennings Formation, Ci-iemung Member. Williams 

 Eoad, Polish Mountain. 



Collection. — Maryland Geological Survey. 



Holopea humilis n. sp. 

 Plate LXIX, Fig. 21 



Description. — Shell very small, depressed subglobose. Spire very small, 

 body volution abruptly enlarging. Volutions three or more; aperture 

 circular; umbilicus not observed. Surface smooth. One specimen shows 

 faint sign of a median revolving carina, rendering reference to Holopea 

 uncertain. This feature, however, may be due to condition of preser- 

 vation. 



Height 8 mm. ; width S mm. 



