220 ROYAL SOCIETY OF CA :aDA 



vonian, certainly not in the Hamilton of the eastern side of the Con- 

 tinent. 



13[. Bliynclionella, cf. emimens. Hall. 



A fragment of a brachial valve showing part of the median fold 

 has shape^ size and plications very similar to the corresponding part of 

 Eatonia medialis; the ribs are lower and finer, however, than in Eatonia 

 and it is referred with doubt to Rliynclionella eminens, Hall. This type 

 of shell also is qnite out of harmony with a middle devonian fauna, and 

 it may be regarded a's evidence of a lower devonian horizon. 



13. Eatonia peculiaris, Hall (narrow variety). 



Two specimens showing unmistakable characteristics of the genus 

 Eatonia are found in the collection, both coming apparently from the 

 same fragment of limestone. The first one, in surface characters and 

 general form is like E. peculiaris, but it is narrower than the typical 

 form. The pedicle valve, in its upper part, has the t}'pical form of 

 E. peculiaris but at the front it is elongate and narrowed, giving to the 

 whole shell an oval contour much like that of Hall's figure of a bra- 

 chial valve on Plate 38, figure 246. ^ Its dimensions are 13.5 x 15,8 mm. 

 The surface markings are similar to figure 24a of the same plate — i.e. 

 the general surface finely lineate, the front margin showing faintly the 

 termination of rather fine plication's. The shell lacks the outer layer 

 and the markings are indistincts 



14. Eatonia, cf. Whitfieldi, Hall. 



The second specimen has a similar narrow oval outline, is about the 

 same size (13.7 x 17.2 mm.). It is a "dorsal'' valve, and shows the 

 median sinus in front, considerably extended toward the opposite valve. 

 The surface is radiatingly plicated as in E. Whitfieldi. The form and 

 eize of this specimen is so nearly like that of specimen 13 of this list that 

 I have some doubt as to separating them, but Uie plications, about nine 

 each side tlie sinus, are distinct in the second specimen|, wliile the first, 

 though in a similar state of preservation, shows only the finely radiate 

 linep-tions characteristic of E. peculiaris. The front edge only shows 

 slight indication of large plications, as is also the case with specimens of 

 that species. I refer the second specimen therefore with doubt to 

 E. Whitfieldi with the impression that more perfect specimens may show 

 that the two 'specimens belong to one species. The presence of these two 

 specimens in the fauna indicates an horizon not later than the Oriskany 



1 Pal. N. Y., Vol. Ill, Pt. 1, 1S59, Plate 38, Fig. 246. 



