RODERTS — OX THE Ul'i'EU LUDLOW TiLESTONES. 
117 
A, A', anterior and posterior occlusor muscular impressions. 
V, muscular markings. 
I am iudelited to Professor Hall, of New York, for these 
beautiful examples of his genus Strophodonta. 
17. Orihisina aiiomula, Schlotheim, Sp. Exterior of the voiira^ valve, and 
area of the dorsal valve. E, area. D, pseudo-deltidium. 
F, foramen. 
17a. Exterior of the dorsal valre. 
18. ,, anomcda. Interior of the dorsal valve. A, A', occlusor 
. mu.scular 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 limestone in 
the neighbourhood of Reval. 
20. „ anomala. A fragment of the i:iterior of the ventral valve, 
fi-om a specimen in the collection of Signor 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 cornstoues, 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 saudy grits and cornstoues rise 
out in undulations, the cornstoues charged with the Cephalaspis 
Lyellii, Pteraspis Lloydii ; and the underlying grits with P. Banksii, 
Pterygotus giyas* and eggs of this crustacean [?] (Parka decijnens) &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. Ladensis, vide corriyenda. 
