Vol. 60.] NON-SEQUENCE BETWEEN KEUPER AND RH^TIC. 349 



23. The Evidence for a Non-Sequence between the Keuper and 

 Rh^etic Series in North- West Gloucestershire and Worces- 

 tershire. By Linsdall Richardson, Esq., F.G.S. (Read 

 June 8th, 1904.) 



[Map on p. 350.] 



During- my investigations of the Rhsetic Series in Worcestershire 

 and North-West Gloucestershire, the results of which are in part 

 chronicled in the ' Proceedings of the Cotteswold Naturalists' Eield- 

 Club ' 1 and in the ' Geological Magazine,' 2 two facts were most 

 noticeable. The first was that above a particular bed in the Rhsetic 

 Series the remaining component deposits were remarkably per- 

 sistent ; while the second was that below that stratigraphical 

 horizon such persistency was not found. The stratigraphical horizon 

 referred to is that of the well-known Bone-Bed of the sections at 

 Aust and Garden Cliffs, and of the less-known Bone-Beds at Wainlode 

 and Sedbury. 



The stratigraphical details may be dealt with first. In most of 

 the sections in Worcestershire a massive bed of sandstone is the 

 equivalent of the thin pyritic Bone-Bed which is so crowded with 

 vertebrate-remains at Garden Cliff, and the contemporaneity of 

 these deposits might be at first doubted. Wainlode Cliff, however, 

 furnishes the clue to the whole question, for in that cliff-section 

 may be observed the change from a thin pyritic stratum (only 

 an inch or so thick) to a micaceous sandstone-bed, usually 

 devoid of vertebrate-remains, and about a foot thick. The latter 

 development, however, contains in some abundance those equivocal 

 casts to which the name of Pullastra arenicola has been so frequently 

 applied ; and also a broad form of what appears to be Modiola 

 minima — but only as obscure casts. The point, however, to which 

 attention is particularly directed is the gradual transition between 

 the two varieties of the Bone-Bed. Below, and separating the 

 Bone-Bed from the ' Tea-Green Marls ' of the Upper Keuper, is 

 a deposit of Black Shale 2 feet thick. The line of junction of 

 the shale with the Keuper Marl may be described as sharply 

 defined, and only very rarely is there an extremely-thin deposit of 

 arenaceous matter intervening between the two formations. At 

 Norton, about 1^- miles to the south-east by east of Wainlode, there 

 is a section in a lane-cutting 300 yards north-east of the church, 

 in which the Bone-Bed is seen as a stratum 15 inches thick, 

 with a few fish-remains and an occasional small quartz-pebble. 

 Black Shales, with a thickness of 16 inches, separate this bed 

 from the * Tea-Green Marls': the line of demarcation between 

 the two being again sharply defined. 



1 Vol. xiv (1903) pp. 127-74, 251-56. 



2 Geol. Mag. 1903, pp. 80-82. 



