162 
OOLITIC OPHIURIDiE. 
shire, but differs from it by the greater proportional length of the rays and more slender 
structure of the same ; from 0. Bamsai/i, Wr., by the absence of the thorny processes 
which project from the free angles of the lateral shields. 
Strati (/rapJiical Position. — This Brittle-star was first discovered by Professor H. 
Roemer between the upper and lower Bone-bed breccias, near Hildesheim, with other 
fossils belonging to the Avicula contorta beds. Several of these specimens were sent 
to me for examination and description by Dr. Dames, of Berlin, and my notes on the 
same were afterwards published, with good figures, in the Zeitschrift der Deutschen 
geologischen Gesellschaft ^ for 1874. 
A few months after I returned the Ophiolepis to Dr. Dames at Berlin, several 
specimens were submitted to me which had been collected from the Avicula contorta 
beds at Garden Cliff, on the Severn, from the dark shales above the Bone-bed. 1 had no 
difficulty in making out the identity of this species with the one I had so recently 
described from Hildesheim, and I brought the facts before the Cotteswold Naturalists' 
Club at one of the regular meetings of the Society, anent the discovery of this little 
Brittle-star in beds of the same age, and at points so far remote from each other as 
Westbury on the Severn, and Hildesheim in Northern Germany. Very soon after this I 
was informed that the same Ophiolepis had been collected in the black shales above the 
Bone-bed, near Leicester. These three discoveries of this Brittle Sea-star, in beds which 
had never previously yielded any remains of Echinoderms, made quite an epoch in the 
history of the Avicula contorta series, inasmuch as a doubt had been entertained as to the 
nature of the conditions under which the Avicula contorta series had been deposited : 
many of the fossils were small dwarfed individuals which it was conjectured might have 
lived under lacustrine conditions. The discovery of a true marine radiate in these shales 
afforded, therefore, positive proof of the conditions under which the Bone-bed breccia 
and its overlying shales had been formed, and recalled to my mind the important observa- 
tion my late colleague. Professor Edward Eorbes, E.E.S., had made on first seeing the 
Avicula contorta and White Lias beds at Lyme Regis : writing to Professor Ramsay, 
E.R.S., in 1847, he said: 
" My visit to Lyme gave me a thoroughly clear idea of the Lias, and the succession 
of its fossils, which I much wanted. I now can picture to myself all the events of its 
formation. At the base of it I saw the so-called White Lias, which, so far as I have seen, 
seems to me to be essentially different from the Lias, and possibly the terminating strata 
of the Triassic series. I broached a notion to Sir Henry De la Beche, from what I saw, 
that the red marls were formed in a great salt inland sea (a sort of Aralo-Caspian), during 
the last state of which the White Lias was formed, that the bed was then either elevated 
and converted into land, or depressed and turned into a part of the ocean, when the 
Liassic fauna came in. This notion is not merely hypothetical ; the fossils of the White 
Lias (very few in species) suggested the idea ; they are curiously representative of the 
existing Caspian fauna. Such a state of things would account for the general and hitherto 
