Reports and Proceedings — Geological Society of London. 429 



3. " The Evidence for a Non-Seqaence between the Keuper and 

 Ehgetic Series in North-West Grloucestershire and Worcestershire." 

 By LinsdaU Kichardson, Esq., F.G.S. 



The section at Wainlode Cliff shows a transition in the 'Bone- 

 bed' from a thin pyritic stratum of an inch or so in thickness and 

 crowded with fish-remains to a micaceous sandstone-bed, usually 

 devoid of such remains and about a foot thick, but containing 

 Strickland's Pullastra arenicola. This sandstone is seen in many 

 Worcestershire sections, and may be called the ' bone-bed equivalent.' 

 Thus, as the bed which is full of vertebrate remains, or the Bone-bed 

 (Bed 15 of the author's sections), can be traced in a single section 

 laterally into a sandstone-bed devoid of those remains, the con- 

 temporaneity of the two developments is considered satisfactorily 

 -established. Particular stress is laid upon the fact that above this 

 main ' Bone-bed ' the component deposits of the Rheetic are remark- 

 ably persistent, while below it such persistency is not found. Black 

 shales are generally present below the Bone-bed or its equivalent 

 in Worcestershire, but in places there comes in a sandstone between 

 them and the ' Tea-green Marls.' At Dunhampstead the Rhsetio 

 rocks are thicker than at any other locality in Worcestershire. At 

 Denny Hill, near Gloucester, the ' Bone-bed ' rests directly on the 

 ' Tea-green Marls ' ; there is no infra-Bone-bed deposit of Ehsetic 

 date. At Garden Cliff, however, a comparatively thick accumulation 

 is seen in that position. The anticlinal and synclinal areas established 

 in the Mid and North Cottes wolds by Mr. S. S. Buckman are 

 referred to ; and it is found that the greatest thicknesses of the 

 Ehsetic rocks under the Bone-bed coincide with synclines, and 

 the least thicknesses with anticlines. The Moreton and Birdlip 

 anticlines are especially mentioned, as also the syncline of Cleeve 

 Hill and that between Painswick and Stroud. Thus Dunhampstead, 

 where the Ehgetic deposits below the Bone-bed are thicker than 

 anywhere else in Worcestershire, is situated on a continuation of the 

 Cleeve Hill synclinal axis ; Denny Hill, where the ' Bone-bed ' rests 

 directly upon the ' Tea-green Marls,' is near the westward con- 

 tinuation of the Birdlip anticline ; and Garden Cliff, where the 

 infra-Bone-bed deposit is thickest, is situated on a continuation of 

 the synclinal axis which runs near Painswick. Thus the earth- 

 pressures recognized in later times were probably at work at the 

 close of the Keuper Period. As the area, once covered by the waters 

 of the Keuper sea and the diminished representatives of that sea 

 ia the form of lakes, gradually sank, the Eheetic ocean slowly 

 encroached upon the land-surface, flowing up the depressions in 

 the undulating expanse of marls, and successive overlaps of the 

 several infra-Bone-bed deposits resulted : the greatest overlap 

 apparently taking place during the formation of the Bone-bed. 

 At those localities where the distribution of the infra-Bone-bed 

 deposits indicates elevation of the Keuper Marls in immediate pre- 

 Ehastic times, it is noticeable that there is also a non-sequence at 

 the base of the Lias. 



