ROWLEYELLA 463 



known character among the terebratuloid shells, it was placed among 

 them tentatively. When the specimens were set up for photographing, 

 on bits of modeling clay, and allowed to remain for several days, the oil 

 from the clay was absorbed by the specimens in such a manner as to bring 

 out clearly the presence of a perfectly preserved spiral brachidium in one 

 of the specimens. The relationships of the genus are clearly with 

 Camaropliorella, the only important differential character which can be 

 pointed out, with our present knowledge, being the absence of the plat- 

 form for muscular attachment in the brachial valve with its margins re- 

 curved to the inner surface of the valve to enclose the two finger-like 

 cavities. If a platform of this sort is present, its margins are entirely 

 free. The attachment of the jugum to the median septum of the brachial 

 valve is another important character of Camarophorella, but it is impossible 

 to determine either the presence or the absence of such an attachment in 

 the specimens of Rowleyella which are available for study. 



ROWLEYELLA FABULITES (Rowley) 

 Plate LXXXII, Figs. 64-69 



1900. Terebratula f abilities Rowley, Am. Geol., vol. 25, p. 265, pi. 5, figs. 



51-53. 

 1911. Rowleyella fabulites Weller, Jour. Geol., vol. 19, p. 448. 



Description. Shell small, terebratuliform, subovate in outline, the 

 greatest width near or in front of the mid-length, the anterior margin 

 rounded. The dimensions of a nearly complete example, but with most 

 of the pedicle valve exfoliated, are : length of pedicle valve 6 mm., length 

 of brachial valve 5.8 mm., greatest width 5 mm., thickness 3.6 mm. 



Pedicle valve convex, with the greatest convexity posterior to the 

 middle, the surface curving abruptly from the umbonal region to the 

 postero-lateral margins and slightly inflected to the cardinal extremities, 

 curving more gently to the antero-lateral and anterior margins, anteriorly 

 from near the middle of the valve the surface is slightly flattened in its 

 median portion, but is not at all depressed in a mesial sinus; the beak 

 is of moderate size, incurved; the foramen of moderate size, subcircular 

 in outline and wholly encroaching upon the umbonal portion of the valve ; 

 the delthyrium not entirely hidden by the incurvature of the beak and 

 apparently closed by a pseudodeltidium. Internally the dental plates 

 are well developed and become joined before reaching the floor of the 

 valve to form a distinct spondylium supported by a strong median 

 septum which reaches anteriorly nearly to the center of the valve. 



Brachial valve a little less convex than the pedicle, the surface curving 

 somewhat more abruptly to the posterior and postero-lateral than to the 

 anterior and antero-lateral margins ; mesial portion scarcely or not at all 

 differentiated from the general curvature of the valve ; the beak incurved 



