MEDINAN, NIAGARAN, AND CHESTER FOSSILS 
109 
Compared with Calymene cedarvillensis from the Cedar ville 
dolomite at Cedarville, Ohio, the anterior border of the cranid- 
ium and the groove intervening between this border and the 
anterior margin of the glabella appears relatively broader, from 
front to rear, in the Jeptha Knob specimens. 
Compared with Calymene vogdesi Foerste, from the Brassfield 
limestone of southwestern Ohio, the posterior margin of the 
pygidium is more strongly curved; the median axis of the pygid- 
ium is relatively broader, and the lateral parts are correspondingly 
narrower in the Jeptha Knob specimens. The median groove 
on the pleural ribs of the pygidium are distinctly defined only 
along the more distal parts of these ribs. 
Undoubtedly other distinguishing features would be noted if 
better specimens of the Jeptha Knob, Cedarville, and Brass- 
field species were at hand. 
Orthis bucheri Sp. nov. 
Plate XV A, fig. I 4 
Brachial valve 26 mm. long, estimated to have been 32 mm. 
wide; nearly flat, with a shallow median depression. With 17 
or 18 primary radiating plications, alternating with which there 
is a secondaiy series, not reaching the beak. Both primary and 
secondary plications tend to be rather angular along their crests, 
and not flattened as in typical Orthis. The structure of the shell 
is strongly fibrous. 
Locality and formation.^ — South spur of South Hill on Jeptha 
Knob, Kentucky; at the base of the crinoidal Brassfield limestone. 
Collected by Prof. Walter H. Bucher, in whose honor the species 
is named. 
H. TRILOBITES FROM THE ST. CLAIR LIMESTONE OF ARKANSAS 
Among the trilobites studied by Prof. Gilbert Van Ingen^^ from 
the St. Clair limestone at Batesville, Arkansas, the following 
never were described or figured: Calymene altirostris, Cyphaspis 
Van Ingen, Gilbert, The Silurian Fauna near Batesville, Arkansas, I : School 
of Mines Quart., vol. 23, 1901, p. 35. 
