PREFA TORY NOTICE. 
IX 
overlapping the Kimeridge Clay finds its base at length 
upon the Oxford Clay. 
All the above deposits of the lower sands were classified 
by Dr Fitton with his Lower Green or Shanklin Sand. 
Little was, however, known of the fossils in the Cambridge¬ 
shire and Bedfordshire sands at the time when his celebrated 
Paper was first published. 
The economical success of the “ diggings ” near Cam¬ 
bridge—and of similar works which had been long carried on 
in Suffolk, among the phosphatized nodules and bones at 
the base of the Crag—naturally led to further searchings 
and to new discoveries. Such are the works near Potton, 
in the ferruginous sands, which are well exposed in the line 
of the Bedford rail-road : and such also are the diggings near 
Upware, on the banks of the Cam, between Cambridge and 
Ely. At both these diggings the works are still in progress, 
and have afforded rich spoils to our Museum. 
The first fossils from these localities were brought to the 
Museum by Mr Seeley. Since then Mr H. Keeping has 
visited the works again nnd again, and not only bestowed 
great personal labour upon them, but has obtained by pur¬ 
chase, in behalf of the Museum, from collectors and labourers 
in the “ diggings,” a multitude of reptilian remains; which 
are now arranged in their nearest anatomical relations; are 
well exhibited; and are described in this Catalogue, after a 
patient study, by my friend Mr Seeley. 
Among these organic spoils are the bones and teeth of 
the Iguanodon and other large Dinosaurs , which seem to 
point to a Wealden fauna for their origin. Are we then to 
conclude that only the upper part of the Bedfordshire sands 
is the representative of the Lower Green (or Shanklin) 
sands of Dr Fitton ? and that the middle and lower part 
(with the Dinosaur remains, &c. &c.) are to be classed with 
the formations of the Weald or Isle of Purbeck ? Or may 
the organic difficulty be met by the hypothesis that the 
Dinosaurian bones (undoubtedly much rubbed and rounded) 
have been drifted out of an older deposit into the middle and 
b 
