194 SUPPLEMENT TO THE 



sinus ; a wide central, elevated, roof-like fold in the ventral valve ; area long and narrow. 

 Surface of valves covered with a number of ribs of unequal size, arranged somewhat in 

 clusters, or with a series of radiating riblets with wide interspaces filled up by shorter and 

 smaller radii. No good interiors have been collected. 

 Length 5, breadth 8 lines. 

 Obs. — This well-marked species was described, but not figured, by Salter in the paper 

 by himself and W. T. Aveline " On the Caradoc Sandstone of Shropshire," and was 

 found in that formation near Hope Bowdler and Cheney Longville, and abundantly in the 

 thin flags of the Horderley section. I have seen examples of the shell from that district. 

 A fine series of specimens, of which I give some figures, were lent to me by Dr. C. 

 Callaway, who had obtained them from the Chatwall Sandstone (Middle Caradoc), 

 south end of Ragleigh Hill, Velnick Stratton. Mr. C. Croft found the fossil likewise in 

 the Caradoc at Ty-isaf, LlansantfFraid. 



120. StrophOxMENa pecten, Linne, sp. Dav., Sil. Mon., PI. XLHI, figs. 1 — 11. 



At p. 306 of my ' Silurian Monograph,' I quote St. pecten from the Wenlock series 

 of the Pentland Hills; since then very fine examples of the species have been collected by 

 Mrs. R. Gray from the Middle Llandovery, at Woodland Point, Girvan, where the 

 shell is large, abundant, and finely preserved. It was also found by the same lady at 

 Newlands, in a light-yellow rock of Middle Llandovery age, and in company wnth Penta- 

 merus undatus, Leptocadia hemispJiarica, and StropJtomena applanata. An allied, but 

 distinct species was also collected by Mrs. R. Gray from the Upper Llandovery, at 

 Cuddyston Glen, Penkill, and Bargany-Pond Burn, in Ayrshire. It is a common shell in 

 the Wenlock series in many localities, and especially in the Pentland Hill. 



]21. Strophomena expansa, 8oio. Dav., Sil. Mon., PI. XLV, figs. 1 — 10; Sil. Sup.,. 



PI. XV, figs. 1—5. 



This species is fully described at p. 312 of my ' Silurian Monograph.' Its vertical 

 range in Scotland is remarkable. Mrs. R. Gray found it abundantly in the Llan- 

 deilo, at Craighead, at Doularg, Bernan Burn, IMinuntion, in Ayrshire ; also in the 

 Middle Caradoc, at Shallock Mill ; in the Lower Llandovery, at JMullock Hill ; and in the 

 Middle Llandovery, at Woodland Point ; all in the Girvan district, in Ayrshire. Mr. 

 Salter, in his paper in vol. vii, p. 171, of the ' Quarterly Journal of the Geological Society,' 



