160 The Official Guide to the 
a few land plants. There is also in this Table Case 
3 a collection of fossils from the Greensand, includ- 
ing Sponges, Oysters, Pectens, etc. The Cambridge 
Greensand has yielded bones and teeth of lizards, 
beside their exuvize or coprolites, which have been 
used for manure. From the Gault, which occurs at 
the north-west of Norfolk with the Greensand, we 
have specimens of Polythecta, Spongia paradoxica, 
Teretrabula, etc., some of them of a deep-red colour, 
obtained from the well-known Red chalk of Hunstan- 
fon. ‘Table Case 4 is devoted to a grand collection of 
fossils from the Lower Chalk, made by the late Mr. C. 
B. Rose. ‘The chalk itself contains numerous remains 
of minute organisms called GiWvéigerina, and in the 
fine calcareous deposit, formed of their remains, shells 
of various descriptions, with corals and sponges 
(Ventriculites), have been preserved. The period of 
duration of the ocean, in whose bed the chalk fossils 
were buried till it was augmented to a thickness of 
hundreds of feet, must have been enormous. From 
the Upper Chalk are shown, in Table Case 4, besides 
numerous shells, remains of ‘Peero tactyles, Plestosaurus, 
and Mosasaurus, some obtained from the Chalk Pit at 
St. James’ Hill, Norwich. The A/osasaurus or Letodon 
anceps was a large saurian ; an entire skeleton, fourteen 
feet long, was once dug out of the Chalk of St. James’ 
Hill. The teeth and bones of the same species of 
saurian are frequently found. The Upper Chalk is 
banded at intervals with flints in which, as many 
examples show, are preserved in a solidified state 
some of the life forms that are only procurable ina 
fragile state from the Chalk. In the Wall Cases, 7 
and 8, and in Table Case 4 are exhibited representa- 
tive fossils of the Upper Chalk and Chalk Marl, 
including teeth of fishes, cephalopods, sea urchins, and 
a specimen of, Tnoceramus digitatus, covered with 
