348 EEPOET — 1891. 



distinct cephalopoda bed, or may be two beds, at the base of the clay, as 

 well as at the top, in some places (Milton and Bagbrook). 



This bed had been previously noticed at Milton, but as the fossils 

 found in it are, on the whole, very similar to those found in what we have 

 usually called the Lower Cephalopoda bed, it was thought to be that bed, 

 and the usually intervening clay absent. This has been completely set at 

 rest now by the finding of a full sequence of the beds at Bugbrook (see 

 Bngbrook section). 



It is at present doubtful whether this bed should be classed as the 

 lowest of the ' Serpentinus ' beds or the highest of the Fish beds. There 

 is much reason for the latter course, as it contains many flattened ammo- 

 nites at Bugbrook like those in the Paper Shales, also Aptychi at both 

 Milton and Bugbrook, and these had never before been found out of the 

 Fish zone. We prefer at present to leave it as a doubtful, or transitional! 

 zone. 



D. — The day may be dark blue when freshly exposed, but gets very 

 light coloured on exposure, and when dry cracks into roughly cubical 

 masses ; the freshly exposed surfaces are often quite purple. In some places 

 it contains numerous little white concretions, as does also the Cephalopoda 

 bed above. 



Thickness a few inches to 5 feet. 



There are very few noticeable fossils in this clay, except just at the 

 base, where the bed often gets shaly, or develops into a distinct hard 

 bed (see sections at Milton and Bugbrook). 



A small group of new forms of Foraminifera have been described by 

 Dr. Rudolph Haeusler ' from clays above the Fish bed at Byfield, collected 

 by Mr. E. A. Walford, F.G.S. — Ophthahnidium Walfordi, 0. •mibeculani- 

 forme, &c. An elaborate comparison is drawn between certain Jurassic 

 Miliolidae of the Jura and those of the neighbourhood of Banbury, Oxon. 



C. Lower Geplialopoda Bed. — The ' Serpentinus ' beds are capped by an 

 argillaceous limestone containing some very large specimens of Ammonites 

 Strangivaysi and others of the falcifer group ; hence the term Cephalopoda 

 bed. It varies from dark blue to light yellow colour, according fo 

 nearness to the surface ; but even the light-coloured pieces exhibit a 

 bluish or violet-coloured interior If sufficiently thick. It often appears 

 water- worn. Thickness about 6 inches. 



The most characteristic fossils of this sub-zone appear to be Ammonites 

 subplanatus, Amberlya capitanea, Opis curvirostris ? and Onustus sjoinosus. 

 All of them rather rare. 



A, B. Communis Beds. — These also consist of a clay capped by a 

 Cephalopoda bed. 



B. The clay is very In'egular in composition, varying much, apparently, 

 in the amount of sand and calcareous matter. It generally contains a 

 large number of small white concretions, as does also the hard bed above ; 

 also small arglllo-calcareous nodules, like larger ones found commonly in 

 higher beds, appear in this for the first time in the Upper Lias. 



The clay is most easily identified by the presence in it of large 

 numbers of small ammonites, chiefly A. communis and A. Holandrei, 

 which are generally quite white. 



Average thickness about 3 feet. 



A. The Ux^per Cephalopoda bed, as the hai-d bed at the top is usually 



' ' Bemerkungen liber einige liasische Miliolidcn," von Rudolph Haeusler, X. 

 JaJirhuchf. Minirahgie, Sec, Bd. I. 1887. 



