WENLOCK GROUP. 


eee Reference to McCoy’s 
Drawers. Synopsis: and Figures of Genera. 
Gdl Hemithyris, p. 201. 
G@dil | Hemithyris nucula, p. 204. 
FC Hemathyris, p. 206. 
Hemithyris crispata, p. 200. 
Gd Hemithyris, p. 207. 
Gd | Hemithyris pentagona, p. 205. 
H. spheroidalis, p. 206. 
FT, Davidsoni, p. 200. 
FC | R. Davidsoni, p. 200, in part. 
Gdl Hemithyris, p. 204. 


Names and References; Observations, &c, 
141 

Numbers and Localities. 





Rhynchonella borealis, var. diodonta, Dalm. 
(Salter, id. p. 883. Davidson, lc. t. 21, figs. 
21—23, Siluria, 2nd ed. pl. 22, fig. 5). 
Rhynchonella nucula, Sow. (Siluria, 2nd ed. 
pl. 22, figs. 1, 2, Foss. 57, fig. 1, p. 250). 
Rhynchonella Stricklandii, Sow. (Siluria, 2nd 
ed. pl. 22, fig. 11, Davidson, l.c. t. 21, 
figs. 1—6). One of the largest species, and 
ranges throughout the central Silurian dis- 
tricts, and South Wales (var. crispata, Dav. 
Sil. Brach. t. 21, fig. 28). 
Rhynchonella Wilsoni, Sow. (Siluria, 2nd 
ed. pl. 22, fig. 13, Davidson, lc. p. 167, 
pl. 23, figs. 1—9). This very common and 
variable shell commenced life in the Wool- 
hope period, and then was largest; dwindled 
away to a very poor and small size in the 
Wenlock limestone, and again became of 
magnificent proportions in Aymestry rocks. 
Rhynchonella Wilsoni, var. Davidsoni, McCoy. 
This was evidently intended by the Professor 
to include his specific term. But it is proba- 
bly only a variety. (Mr Davidson has 
figured it extremely well in the fifth volume 
of the Bull. Soc. Géol. de France, 2nd ser. 
pl. 3, fig. 36, as R. spherica, a name pre- 
viously adopted.) 
Rhynchonella navicula, Sow. (Siluria, 2nd ed. 
pl. 22, fig. 12, Davidson, Sil. Br. t. 22, figs. 
20—23), is not rare in the Wenlock Shale, 
Dinas Bran, Llangollen, but never found at 
Dudley or Wenlock in the limestone. 
Pentamerus, J. Sowerby, Sen. An excellent 
name for a shell which is literally divided 
into five chambers by vertical plates; so 
much so that the two halves of the shell 
come readily apart under the hammer. No 
Brachiopod so thoroughly shews the true 

a. 647, Dudley, F.C. 
a. 381, Coed Sion, Llanga- 
doc; b. 753, Golden Grove, 
Llandeilo, large (W. Shale). 
a. 757, Dudley, F.C.; 
a. 758, Malvern, Sedgley? 
b.753, Dudley, F.C.; a.380, 
as H. pentagona, Clungun- 
ford, W. Shale? a. 672, 
var. Falfield, Tortworth 
(Earl Ducie) ; a. 677, var., 
Ledbury (as H. spherowda- 
lis); a. 673, figured speci- 
men, Dudley. 
a. 762 is fig. 43 of the 
work cited; a. 763, also 
figured; a, 764 is a var, 
with very few ribs, and 
a. 765 an elongated form; 
a. 766, interior, Dudley, 
F.C. 
b. 752, Wenlock Shale, 
Dinas Bran, Llangollen, §, 
Wales, 
