532 Seeley— On the Cretaceous Beds at Ely. 
carbonized wood. At Gamlingay the wood was compressed, infiltra- 
ted with iron, and drilled by Teredo. Near Potten a section shows 
a seam about nine inches thick, of perfectly rounded and rather large 
pebbles, between fine sand. At Sandy, resting on the Oxford Clay, 
the pale ferruginous sands form a cliff nearly 100 feet high over- 
looking the western plain. 
At Ely the Sand-rock appears to rest quite conformably on a dark 
slate-blue clay containing Lingula ovalis, which is Kimmeridge Clay 
g). So that though in a diagram section in a former paper (vol. L., 
p- 151), Chalk and Kimmeridge Clay stand side by side, yet in another 
part of the section the missing beds, very thin, are found in their 
proper places ; so that the fault at the north end of the pit, where 
least, has only let down the Kimmeridge Clay for some thirty feet, 
bringing its upper beds low in the section. 
The clay has the usual shaly laminated character, with large 
septarian concretions in layers, and numerous fossils, but they are 
compressed, and the frailest occur as casts. Ammonites biplex, A. 
perarmatus, Patella latissima, Exogyra virgula, Ostrea leviuseula, 
Lingula ovalis, and Serpula tetragona are the commonest fossils. 
Trigonellites are very numerous relatively to Ammonites, and in the 
upper part of the bed there is a good deal of wood. 
The Reptiles are species of Ichthyosaurus, Plesiosaurus, Plio- 
saurus, Steneosaurus, Teleosaurus, Chelonia, and perhaps Jguano- 
don. 'The Fishes are species of Asteracanthus, Pycnodus, Gyrodus, 
Hybodus, Celacanthus, and Edaphodon, with Sphenonchus. 
x 
Fig. 2.— Section 1n THE Ery Prr. 
a. Surface-gravel. 6. Gravel. c. Boulder-clay. d. Gault. 
e. Alternations of Clay and Sand. Jf. Shanklin Sands. g. Kimmeridge Clay. 
At the point in the general section where the Cretaceous beds are 
broken off by Boulder-clay is the section, Fig. 2, taken at right 
angles to the other, which shows that, instead of being wanting, the 
