GEOLOGY OF SHROPSHIRE. 207 



is limited by the Hoar Edge Grits, the lowest beds of the Caradoc. I 

 have recently detected the shales in the hoUow between the Lawley and 

 Hoar Edge, on the south-east side of Caer Caradoc, and west of the 

 Longmynd, at the base of the Stiper Stones. 



2. — Lithological Characters. — The Shineton Shales are dark blue, 

 weathering to oKve and yellow, the colouring iron-oxide sometimes 

 separating as a stain or film. They are micaceous, thin bedded, soft, 

 and rather fissile. I have rarely had any difficulty in distinguishing them 

 from the Harnage Shales, either in situ or in hand specimens. 



3. — Dip and Strike. — The general strike of the shales is about south- 

 west, agreeing with the direction of the great fault and of the so-called 

 igneous elevations of the district ; but towards the south-west end of the 

 area it bends round to the west, corresponding with the strike of the 

 overlying Caradoc. The mean dip of the greater part of the shales is 

 about 30" to the south-east ; but in the lower part of the series, where 

 they approach the fault, it becomes higher, then veiiiical, than dips 

 steeply to the north-west, the evidence pointing towards the existence of 

 an anticlinal. The thickness of the shales is probably not less than 

 1,500 feet. 



4. — Stratigrapliical Position. — The Shineton Shales underlie the May 

 Hill Sandstone unconformably ; they are therefore older than that 

 formation by an interval. They underhe the Caradoc, and are, of course, 

 of greater antiquity. They overlie, probably unconformably, the 

 Hollybush Sandstone. I shall endeavour to show that they are of 

 Tx'emadoc age. 



{a..)— Evidence from Fossils. — Most of the Shineton forms are new 

 specifically, and some of the genera are also new. The species which are 

 of geological value are the following : — -Conocorrjplie vionile, Salter. 

 Conocorijphe proper is distinctive of Lower Cambrian rocks, and this 

 species is truly typical of the genus. Olcnus Salteri, Callaway, and O. 

 triarthrus. Call., new species of a genus which usually characterizes strata 

 of the age of the Lingula Flags. Agnostus dux, Call., similar to certain 

 St. David's forms, (Menevian.) Lingulella Nicholsoni, Call., x'esembling 

 L. lepis, a Tremadoc species. Asaphellus Homfrayi, Salt., common in 

 the Upper Tremadoc at Portmadoc. 



(b.) — Evidence from Correlation luith Rocks in other Localities. — 

 Dictyonema beds at Pedwardine. — Shales identical lithologically with the 

 Shineton Shales, and containing Lingulella Nicholsoni, one found at 

 Pedwardine, twenty-five miles to the south-west of Shineton, on the same 

 line of strike. They also contain Dictyonema sociale, which has not yet 

 been found at Shineton. 



Dictyonema Beds at Blalvern.—Ovevlying the Qlenus Shales near 

 Wliite-leaved Oak, are light-coloured shales, similar to the Shineton and 

 Pedwardine beds, and containing two Shineton forms, Platypeltis 

 Croftii, CaU., and Conophrys salopiensis, Call., together with Dictyonema 

 sociale, Salt. 



A comparison of the three formations at Shineton, Pedwardine, and 

 Malvern is very interesting. The Shineton beds are connected with the 



