228 MOLLUSCAN REMAINS IN THE WARWICKSHIRE TRIAS. 
red and grey marls and sandstone, and is termed the “ Keuper.” 
Both Divisions occur on the Continent ; and in Germany and 
France are divided by a middle group of rocks, “ the Muschelkalk,” 
which is highly fossiliferous, possessing a characteristic marine 
fauna. The Muschelkalk is not represented in England, unless we 
except certain dolomitic conglomerates found in the Bristol area. 
The organic remains of the British Trias are comparatively 
few ; probably no other series of beds of equal thickness exhibits so 
scanty an array of fossils as do the sandstone and marls of this 
group. The reasons for this are very apparent; the conditions 
under which the beds were deposited were not congenial to the 
preservation of life. The waters were highly saliferous, containing 
sulphate of lime and salt in solution, which became deposited as 
the evaporation of the water proceeded. Those organisms which 
were hardy enough to adapt themselves to the changing environ¬ 
ment existed as stunted and aberrant forms ; the weaker died out. 
It is to the Keuper or Upper Division that we must turn to 
obtain evidences of the scanty fauna and flora which existed in Triassic 
times. The Keuper marls of Warwickshire, Worcestershire, South 
Devon, and Scotland have yielded the remains of ganoid fishes 
(■Hybodus Keuperi, Acrodus minimus, &c.), and Deinosaurs (Hypero- 
dapedon, Mastodontosaurus, &c.). But not until quite recently 
have evidences of the existence of a Molluscan fauna been forth¬ 
coming from the British Keuper. On the Continent a large suite of 
specimens have been obtained; and the discovery of shell-remains 
in a thin bone-bed in the Lower Keuper marls near Warwick is of 
great interest and importance. Unfortunately the specimens are 
very fragmentary, the fine sandy conglomerate in which they are 
embedded not being suitable material for the preservation of fossil 
remains. They consist of internal casts, and are associated with 
the teeth, dorsal spines, scales, and bone fragments of such 
fishes as Lophodus , Hybodus, &c. They are all representa¬ 
tives of the lowest group of Mollusca, viz., the Lamelli- 
branchiata, and they present structural peculiarities imposed 
by the surrounding conditions under which they live. One 
form ( Myophoria ), a smooth-surfaced, obliquely-keeled shell, is 
October, 1893. 
