On two Species of Microscopic Shells found in the Lias.

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Abstract
The shells of the microscopic order Foraminifera , which occur so abundantly in the cretaceous and tertiary series, are found much more rarely as we descend through the secondary formations. Examples of them have indeed occurred both in the oolitic and the palæozoic series, but I believe that these fossils have not hitherto been met with in the lias. The Rev. P.B. Brodie, while pursuing his interesting and successful researches into the fossil insects of the lower lias, was the first to discover these minute objects. In a bed of yellowish shaly stone, a few feet above the ‘insect limestone’ of wainlode cliff, Gloucesrtershire, he detected small white dots about 1/50th of an inch in diameter, which when examined by a powerful microscope prove to discoid spiral shells, apparently unattached, with five to six smooth, rounded, narrow volutions, devoid of striations or any other distinctive characters. As there are no traces of concamerations, we perhaps ought to refer them to the serpulidæ rather than the Foraminifera , although their extreme minuteness would point to be latter family as a more probable clue to their affinities. It has been suggested to me that their characters resemble those of the genus Orbis of Lea, and I will therefore denominate the fossil provisionally Orbis infimus (see figure a). These fossils also occur ina similar bed of shaly limestone near the base of the lias at Cleeve Bank, between Evesham and Bidford. Along with them I here obtained one specimen of an equally minute fossil, which

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