Chap. X.] 
UPPER SILURIAN BRACHIOPODS. 
227 
Wenlock slabs j Meristella Circe, Barr., a Bohemian fossil, occurs with the com- 
mon Meristella tumida at Walsall ; Retzia Salteri (Foss. 58. f. 7) and its var. 
Baylei (f. 8, 9), Rhynchonella Lewisii (f. 2), and Retzia Bouchardi (f. 4) are 
common Wenlock species j R. Barrandii, f. 5, Porambonites Capewellii, f. 6, and 
Atrypa Grayii, f. 3 (a strange twisted species), are rare Dudley fossils. Rhyn- 
chonella nucula, f. 1, is the commonest of all the Rhynchonellse of the Upper Lud- 
low rock. Imperfect specimens of it are figured in PL XXII. f. 1, 2. 
Three Pentameri only were formerly described from the upper division, 
namely P. linguifer, P. galeatus, and P. Knightii (see Plates XXI. & XXII.). To 
these may now be added Stricklandinia (Pentamerus) lirata, Foss. 15. f. 3, p. 90, 
found in the Woolhope limestone, which may be considered to be strictly a transi- 
tional species, occurring in the very lowest beds of this division, and in the upper- 
most strata of the Llandovery formation, at May Hill, Gloucestershire, at Pres- 
teign, and also in Pembrokeshire. 
Some species of Orthis have been already quoted, Chap. VI., as very common 
Fossils (59). Upper Silurian Brachiopoda. 
I. Orthis Bouchardi, Davidson. 2. O. calligramma, Dalm. (O. Davidsoni, de Vera.). 
3. Strophomena pecten, Linn. 4. Str. funiculata, M'Coy. 5. Interior of the same. 
6. Str. imbrex, Pander. 7. Interior of dorsal valve of the same. 8. Str. antiquata, 
Sow., full-grown (half the natural size). 
in the Wenlock and Dudley limestone. 0. Bouchardi, Davidson *, Foss. 59. f. 1, 
0. Lewisii, Dav., and 0. sequivalvis, Dav., are rare in the same formation ; and 
so is 0. calligramma, Dalm., adverted to at p. 192, if the shell here figured, 
Foss. 59. f. 2, be not a distinct species (0. Davidsoni) as de Verneuil and 
M'Coy suppose. 
Strophomena antiquata, Foss. 59. f. 8, grew five or six times the size of the 
figure in my original work (see PL XX. f. 18). Strophomena funiculata, f. 4, 
and Str. imbrex, f. 6, 7, are common Wenlock species. Str. corrugata, Portlock, 
is a beautiful but rare Wenlock shell, which has been already cited in the 
Lower division, where it is plentiful. Str. pecten, f. 3, though common both in 
Lower and Upper Silurian, escaped notice when the 1 Silurian System ' was 
published. Str. applanata, Salter, a small species resembling the last, occurs 
sparingly in both divisions. 
Lingula Lewisii, PL XX. f. 5, is one of the commonest species of the Middle 
* Bull. Soc. Gre'ol. de France, 2 se'r. t. v. p. 309, there ; but, as this is a genus never found below 
1848. This memoir contains figures of all the the limits of the Devonian strata, it is well to note 
British Upper Silurian species then known, in- that Mr. Davidson now believes it to be an im- 
cluding a great many not before described. The perfect Strophomena depressa, a common Silurian 
reader will find a single Produetus described species. 
<j2 
