420 G. L. COLLIE — OEDOVICIAN SECTION XEAK BELLEFONTE 



sylvania species, while the concentric lines are better shown in the 

 Canadian species. The Canadian species also show stronger concavity 

 beneath the peripheral edge. 



Locality and formation, Bellefonte, Pennsylvania, in the upper Beek- 

 mantown horizon. Collected by G. L. Collie. 



PROTOWARTHIA TENUISSIMA SP. NOV. 



Plate 59, figures 10 and 11, lateral and dorsal views 



Lenticular, greatly compressed ; acute dorsum ; vertical diameter, 23 

 millimeters ; greatest width just above the umbilicus, 6 millimeters. 

 From the umbilicus the surface ascends by a gentle convex slope to the 

 acute dorsal edge. 



Umbilicus small, scarcely 2 millimeters across, rounded on the edge. 

 The aperture is compressed ovate, indented two-fifths of its height by the 

 penultimate whorl. Narrow emargination in the outer lip, which extends 

 back about one-fifth of the circumference of the outer whorl. Surface 

 smooth, except for a few growth lines, which begin at the umbilicus and 

 follow the edge of the aperture, bending back around the emargination. 



The specimens of this species that have been collected all show the 

 extremely compressed character which gives the name to the species. 

 At first it was believed that the individuals were compressed specimens 

 of P. cancellaia, but quite a number of specimens collected invariably 

 show the same attenuated condition without evidence of the distortion 

 which usually appears in crushed fossils. It is now believed that the 

 compression is a specific character. In other respects the new species 

 resembles P. cancellata, though there is no evidence of a cancellated 

 surface. 



Locality and formation, Bellefonte, Pennsylvania, in the lower portion 

 of the Trenton formation. Collected by G. L. Collie. 



PR TO WA R THIA R OSS I SP. NO V. 



Plate 59, fijj^ures 6 and 7, lateral and apertural views X 2 diameters 



Shell small and globose, rarely exceeding 8 millimeters in diameter, 

 the width of the aperture equaling the height ; whorls broad, inflated, 

 and strongly convex ; umbilicus about one-fourth the diameter of the 

 shell, subacute on the edge. No emargination visible, aperture sub- 

 quadrate, expanded laterally, indented one-third its height b}^ the pre- 

 ceding whorl. Surface smooth, without apparent growth lines. 



A small and primitive type of Protowarthia. It differs from P. bilobatus, 

 which it most resembles, in being very much smaller and in possessing 

 no emargination. 



Locality and formation, Bellefonte, Pennsylvania, in the upper Beek- 

 mantown group. Collected b}^ G. L. Collie. 



