98 Evolution and Distribution of Fishes 



These pass upwards conformably into a series of red 

 marls, with yellowish gray and pink sandstone, containing 

 Pteraspis and Cephalaspis, and undoubtedly forming the 

 base of the Cornstone series of the Old Red Sandstone. 



J. W. Salter in commenting on the fossils (p. 162) 

 gives Pachytheca sphaerica as a probable plant found with 

 the animals. Now the presence of marine fossils in the 

 Aymestry and in Upper Ludlow groups, and even the 

 continued occurrence of species of Lingiila in at least some 

 strata of the Downton and other higher beds, would incline 

 anyone who had even a slight "marine" bias to view all 

 of the beds and their organisms as marine. And in the 

 subsequent papers of Roberts-Randall (5^:229) and 

 of Randall (55:494) this is more or less accepted though 

 with a query. For in the latter paper Randall favored the 

 idea of a gradual change from marine surroundings in 

 the lower rocks to freshwater conditions above. The care- 

 ful record from Linley Brook of rock successions, given in 

 the earlier of these two papers is subjoined, as being of 

 value from the palaeontological standpoint. 



VERTICAL SECTION OF THE BEDS EXPOSED AT LINLEY BROOK. 



(a) Northern drift with boulders Feet. Inches. 



(b) Upper Coal Measures 



(c) Red Clays, unfossiliferous 6 o 



(d) Light colored grits with plant remains 20 o 



(e) Hard micaceous grits, charged with fish-remains. 7 o 



Upper Bone Bed. 



(f) Flagstones with current markings i 9 



(g) Micaceous sandy grits with Lingulae o 11 



(h) Greenish irregularly laminated rock with con- 

 glomerate I o 



(i) Hard calcareous grit with broken Lingulae 1 o 



(k) Laminated micaceous and sandy shale 20 o 



(I) Gray micaceous grit o 6 



(m) Micaceous ferruginous clays 6 o 



(n) Yellowish sandstones (Downton Series) with 

 Beyrichiae and Lingulae, also two or more 

 ferruginous bands with large quantities of 

 dermal studs of Tlielodus, fragments of 



Lingulae etc 8 o 



Lower or Ludlow Bone Bed. 

 (o) Hard calcareous shales with fish-remains, Lingu- 



1 ae etc 6 o 



(p) Flaggy bed of impure limestone with Serpulites. . 4 o 



(q) Hard impure limestone (Aymestry Series) 



82 2 



