334 REPORT— 1891. 



Repo7't of the Committee, consisting of Dr. H. Woodward {Chair- 

 man), Messrs. W. D. Crick, T. Gt. G-eorge, Wm. Hull, E. A. 

 Walford, E. Wilson, H. B. Woodward, and Beeby Thompson 

 {Secretary), to luorh the very Fossiliferous Transition Bed be- 

 tiveen the Middle and Upper Lias in Northamptonshire, in 

 order to obtain a more clear idea of its fauna, and to fix the 

 position of certain sp)ecies of fossil fish, and more fully investi- 

 gate the horizon on which they occur. {Drawn up by the 

 Secretary.) 



In 1863 Mr. E. C. H. Day published in the ' Journal of the Geological 

 Society ' a paper entitled ' On the Middle and Upper Lias of the Dorset- 

 shire Coast.' In this paper, page 293 of the Journal, Mr. Day describes 

 ' The Marlstone "with its Plenrotomaria Bed.' From this description it 

 appears that the marlstone rock bed is capped by a remarkable bed of 

 small thickness, abounding in gasteropods and other fossils, which indicate 

 — particularly the ammonites — a passage bed between the Middle and 

 Upper Lias. Mr. Day considers that the Fish bed of Ilminster and 

 Dumbleton is absent. 



In 1865-66 Mr. Charles Moore published, in the ' Proceedings of the 

 Somersetshire Archreological and Natural History Society,' a long paper 

 ' On the Middle and Upper Lias of the South-West of England,' in which 

 he describes a zone situated between the Marlstone and Fish bed under 

 the name of the Leptcp.na beds. 



In 1872 Mr. Thos. Beesley read a paper before the Warwickshire 

 Naturalists and Archaeologists' Field Club entitled ' A Sketch of the 

 Geology of the Neighbourhood of Banbury,' in which mention was made 

 oi. a passage bed between the Middle and Upper Lias. This paper was 

 published in the ' Proceedings ' of the Society. 



In 1876 Messrs. Tate and Blake published their ' Yorkshire Lias,' 

 in which they described a zone of the Middle Lias, under the name of 

 the Zo7ie of Amvwuites Annidatus, occupying the position of the Pleuro- 

 omaria bed of Day and the Lepttena beds of Moore. 



Again, in 1879 Mr. Edwin A. Walford published in the ' Proceedings 

 of the Warwickshire Naturalists and Archajologists' Field Club ' a paper 

 ' On Some Middle and Upper Lias Beds in the Neighbourhood of Ban- 

 bury.' This paper describes a bed situated between the ]\Iailstone rock 

 bed and the Upper Lias Fish bed, in the south-western parts of North- 

 amptonshire, under the name of the Transition bed. 



Some few years ago two of the members of this committee — Messrs. 

 Thompson and Crick — detected the same bed in a rather large number of 

 widely separated parts of Northamptonshire, and as far north as Tilton, 

 in Leicestershire.' 



As it seemed of considerable interest to more thoroughly investigate 

 this bed and those immediately above and below it, and there was much 

 difficulty in doing so owing to nearly all the Marlstone quarries being 

 closed, the British Association kindly made a grant of money for the 

 purpose. The present report gives the results of the investigation. 



' Mr. E. Wilson had previously described the deposits at Tilton, but did nots 

 separate the Transition bed from the rock bed. 



