896 Geological Society : — 



the view of the older observers that the Marls are aqueous deposits, 

 though possibly containing much wind-borne material, deposited in 

 a shallow lake undergoing strong evaporation and subjected to 

 occasional irruptions of the sea. They represent the closing phase 

 of Triassic ' continental ' conditions in the English Midlands, when 

 the slow subsidence which was soon to bring in marine lihaetic and 

 Liassic deposits was in progress, and produced that overlapping of 

 the Keuper rocks on to the higher grounds of the Triassic land- 

 surface which is observable in the neighbouring districts of the 

 Lickey Hills, Nuneaton, and Charnwood Forest. 



The tectonics of the area are explained by sections and by a con- 

 tour-map of the upper surface of the Arden Sandstone, which show 

 that, while the beds as a whole are tilted south-eastwards, 

 there are numerous shallow cross-folds with Charnian (north-west 

 to south-east) axes and others with Pennine (north to south) axes. 

 The majority of the faults have a Charnian trend. 



The paper also records three well-borings through the Marls into 

 the Lower Keuper Sandstone. 



February 7th, 1912.— Prof. W. W. Watts, Sc.D., LL.D., M.Sc, 

 F.P.S., President, in the Chair. 



The following communication was read : — 



1 On an Inlier of Longmyndian and Cambrian at Pedwardine 

 (Herefordshire).' By Arthur Hubert Cox, M.Sc, Ph.D., F.G.S. 



The inlier in question comprises a strip of country about a mile 

 in length and half a mile in breadth, situated near the border of 

 Herefordshire and Radnorshire, about 15 miles south of Church 

 Stretton. It lies on the well-known north-east and south-west 

 line of dislocation which extends through that town. 



Wenlock and Ludlow beds occupy most of the area around 

 Pedwardine, but the occurrence of Cambrian Shale yielding 

 Dictyonema has long been known. The Dictyonema Shales dip 

 steeply westwards towards a series of red and green conglomerates 

 and grits, with which an occasional thin shale-band is interbedded. 



The latter beds, previously mapped as Llandovery, are here 

 referred to the Longmyndian. They also dip steeply westwards, 

 and have suffered considerable disturbance, accompanied by over- 

 thrusting from the west. They are quite unfossiliferous, and 

 neither on lithological nor on structural grounds can they be 

 regarded as Llandovery strata resting unconformably upon the 

 Cambrian. Their nearest equivalents are found among the Long- 

 myndian grits at Hopesay, and in the Bayston Group of the main 

 Longmynd area. These Longmyndian grits at Pedwardine have 

 apparently been carried south-eastwards over the Cambrian along 

 an almost horizontal thrust-plane. 



There is also present a small remnant of Bala grits which dip 

 gently eastwards, and rest with strong unconformity upon the 

 Cambrian shales. The undisturbed character of these Bala beds 

 suggests that the neighbouring thrust may be of pre-Bala date. 



Later faulting along a north- and-south line has brought the 

 members of these older formations against Wenlock and Ludlow 



