EXPLANATION OF THE PLATES. 
PLATE XX. 
FOSSILS OF THE WENLOCK ROCKS. 
MOLLUSCA.—BRACHIOPODA. 
Fic. 1.—a, 6, c. SPIRIFERA PLICATELLA, Linneus, sp. 
S. interlineatus and S. radiatus, Sil. Syst., pp. 614, 624. 
S. plicatella and vars. radiata and globosa. Brit. Sil. Brach., pp. 84-89, 
pleax. 
a, b,c. Original. ‘Three views of the same shell; from Wenlock limestone ; 
Dormington lime quarries, Woolhope district. Mus. G. 8. I. 
Luanpovery To Luptow.—Sil., 4th ed., p. 528. Sp. plicatella occurs 
especially plentiful in the Wenlock shales in the neighbourhood of Dudley 
and Walsall, Staffordshire ; and the Wenlock limestone of May Hill; of 
Woolhope, Ledbury, Herefordshire ; Benthall Edge, &c.; and in the 
Aymestry limestone, of Aymestry. Brit. Sil. Brach., p. 86. Many other 
localities are given for this species with its varieties Cyrtena radiata and 
interlineata in Mem. G., S., vol. ii., part i., p. 292, 3. The var. radiata 
is also stated, on the authority of Mr. Salter, to occur in the Lower Llan- 
dovery rocks of the Quakers’ Burial Ground, near Welshpool; the only 
locality known in rocks below the Upper Silurian. Brit. Sil. Brach., 
p- 88. 
Fig. 2.—a, 6. SPIRIFERA ELEVATA, Dalman. 
S. oetoplicatus, Sil. Syst., p. 624. S. elevata, Sil., 4th ed., pl. xxi., fig. 5, 6. 
a, b. Original. Two views of the same shell. Wenlock limestone, Wenlock 
Edge. Mus. G.S. I. 
LiaNDOVERY to LupLtow.—Sil., 4th ed., p. 528. “This shell is one of the 
most common in our Upper Silurian rocks; it varies considerably in shape 
and number of ‘ribs.’ It occurs in the Upper Llandovery beds at Damory 
Bridge, Tortworth ; also not uncommonly in the Llandovery beds at May 
Hill and Huntley Hill, &e.; in the Wenlock limestone of Dudley ; and 
numerous other localities in Shropshire, Herefordshire, and Gloucester- 
shire; in the Lower Wenlock (or Denbigh) grit beds at several places in 
North Wales and Wenlock beds in South Wales and Dingle, Co. Kerry; 
in Lower Ludlow, Abberley, and Usk district; also in Ludlow beds at 
Kendal in Westmoreland,” &e. Brit. Sil. Brach., pp. 96, 7. 
Fic. 3.—a, b. MuristeLLA TumIDA, Dalman, sp. 
Atrypa tenuistriata, Sil. Syst., p. 623. Meristella tumida, Sil., 4th ed., pl. 
xxil., fig. 20. 
