ROBERTS — ON THE UPPER LUDLOW TILESTONES. 



117 



A, A', anterior and posterior occlusor muscular impressions. 

 V, muscular markings. 



I am indebted to Professor Hall, of New York, for these 

 beautiful examples of his genus Strophodonta. 



17. Orthisina anomala, Schlotheim, Sp. Exterior of the '2;ew^7-aZ valve, and 



area of the dorsal valve. E, area. D, pseudo-deltidium. 

 F, foramen. 



17a. Exterior of the dorsal valve. 



18. anomala. Interior of the dorsal valve. A, A', occlusor 



muscular impressions. 



19. „ anomala. Interior of the ventral valve. These beautiful 



specimens were kindly given to me by Professor Dr. Schmidt, 

 of Dorpat, and were obtained from the Silurian hmestone in 

 the neighbourhood of Reval. 



20. ,, anomala. A fragment of the interior of the ventral valve, 



from a specimen in the collection of Signer Michelotti, of 

 Turin. For this drawing I am indebted to Professor Suess, 

 of Vienna. 



ON THE UPPER LUDLOW TILESTONES. 

 By George E. Roberts, of Kidderminster. 



The Tilestone passage-beds between the Upper Ludlow rocks and 

 those cornstones, now established as the natural base of the Old Red 

 Sandstone, are, from the interesting character of their animal contents, 

 attracting the greatest interest. I think it would be of value if the 

 pages of the Geologist were open to detailed descriptions of the litho- 

 logical character and fossils of these " Tilestones," as exposed in 

 different parts of Shropshire, Worcestershire, and Herefordshire. A 

 comparison may thus be instituted which would greatly aid our com- 

 prehension of them. 



The Upper Tilestone series displayed in my own neighbourhood, 

 is thus described in the new edition of " Siluria" : — 



In the red ground, two miles north of Bewdley, near Trimpley, 

 in Worcestershire, greyish coloured sandy grits and cornstones rise 

 out in undulations, the cornstones charged with the Cephalaspis 

 Lyellii, Fteraspis Lloydii ; and the underlying grits with P. Banhsii, 

 Fterygotus gigas,'^ and eggs of this crustacean [?] {Parha decipiens) &c. 

 with many remains of plants, including the small Lycopodiaceous 

 sporangia." 



This condensed matter I will now give in detail ; for as every fossil 



* P. Ludensis, vide corrigenda. 



