0^ EXCAVAtlONS IJJ tHE PALAEOZOIC ROCKS OF WALES, &C. 2S9 



Interval of about 20 feet, in which no rock showed at the bottom of 



the trench, 



b. The ' Wrekin Quartaite.' 



Pt. In. 

 J, Broken angular fragments of fine-gfained Quartzite, totlch brec- 



ciated, the cracks onlj' partially tilled . . . about 4 

 b^ Bottom of trench showing no bedded rock but much clayey 



material with fragments of Quartzite flags 1 to 2 inches thick, 



representing a thickness of ..... about 10 

 Jj Coarse granular Quartzite, much broken and weathered in places 



to a dark incoherent grit ...... about 4 



h^ Well-bedded coarse-grained Quartzite, dipping west at about 85°, 



underlain by a clay-partiiig ...... 



?>3 Compact glistening fine-grained Quartzite and clay -parting . 

 bg Compact glistening Hne-grained Quartzite and clay-parting . 



b, Coarse-grained white Quartzite, weathering in places to a dark 



incoherent quartz grit . . . . . 



Total thickness of Quartzite seen .... 



Possible Fault: — 



c. Dolerite, weathered or sheared into small lenticles ^ to i inch 



thick and much decomposed, becoming rather more compact 

 at a distance of 2 feet from the Quartzite. 



This Section is of interest as showing :— 



A. The general nature of the higher beds of the Wrekin" Quartzite with their 



varying thicknesses and clayey partings ; 



B. A continuous section of about 6(3 feet of the I^ower Comley Sandstone, 



with the occurrence in it of a HyoUthns and some calcareous gritty 

 bands and shales ; 



C. A certain amount of graduation from beds with a thoroughly quartzite 



facies to those of the sandstone facies. 



It is uncertain whether the 20 feet interval between the two forma- 

 tions represents a fault or not. The subsoil at this point is a very loose 

 sandy gravel (probably glacial), and it was considered unsafe to deepen 

 the narrow trench sufficiently to find solid rock. 



Excavation No. 5. — Hill House Ridye, North End. 



At the northern extremity of Hill House Ridge (see map) a small 

 quarry was opened some ten or fifteen years ago for the purpose of 

 extracting stone for rough walling from two strong beds of grey grit, 

 beneath which lies a band of dark brown incoherent grit. In this dark 

 grit I had previously found some casts of fragments of trilobites. 



In order to endeavour if possible to fix the position of these grits in 

 the general Comley Series, I had trench'=!S cut crossing the strike of the 

 beds to east and west of the little quarry. 



The section thus exposed divides itself into three parts : (1) The 

 trench east of the quarry ; (2) The quarry itself ; and (3) The trench 

 west of the quarry. 



