﻿Vol. 64.] THE FOSSILIFEROTJS SILURIAN ROCKS OF TORTWOETH. 515 



back of the hedge has exposed a considerably larger and better 

 section of ashy limestone and other material occupying a hollow in 

 the trap (see fig. 2, below). The section is as follows : — 



ThicJcness in feet inches 



(5) Surface-soil — — 



(4) Limestone, sometimes nearly pure, sometimes full of 

 minute ashy particles, occasionally with bigger lapilli 

 of vesicular basalt. Crowded with fossils, chiefly 



brachiopods 1 



(3) Band of compact grit, containing Stricklandinia lirata 



and Spirifer plicatelhis var. radiatus 1 to 3 



(2) Band of gritty limestone, when unweathered containing 

 in places much finely-divided ashy material, but as 

 a rule considerably decalcified. Crowded with fossils, 



chiefly corals 1 



(1) Compact fine-grained material, resembling baked shale 



and resting on the trap 1 to 3 



Fig. 2. — Vieiv of part of CuUimore's Quarry, Cliarjield Green. 



[Scale: 1 inch = rather less than 1 foot.] 



A = Patch of trap surrounded by sedimentary material. 

 B = Patch of sedimentary material enclosed in the trap. 



The section above described appears to be the same as that 

 recorded by Weaver, ^ and illustrated by his pi. xxxix, fig. 2. The 

 two fossiliferous bands seem to be those which he says are 



* composed of sandstone, slate-clay, carbonate of lime, oxide of iron, and trap- 

 like matt,er, intermixed . . . .' 



He mentions the occurrence of numerous corals, bivalves, and a 

 triiobite in these bands. He represents, however, the strata as 



^ Trans. Geol. Soc. ser. 2, vol. i, pt. ii (1824) p. 334. 



