530 Seeley—On the Cretaceous Beds at Ely. 
its way south-west. Very many sections have been exposed all 
along the line of its outcrop, away to Bedfordshire. But from its 
thinness, it forms no feature in the country. Outliers, and espe- 
cially one between Ely and St. Ives, at Haddenham, show that it 
was formerly wider spread. 
Fig. 1.—SxEcrion NEAR Hry. 
a. Gravel. 6. Boulder-elay.. c. Chalk. d. Upper Greensand (between ¢ and ¢). 
e. Gault. f. Shanklin Sand g. Kimmeridge Clay. 
It is out of this insignificant stratum, constant in thickness as it 
is in position, and extending over the county from Ashwell to 
Mildenhall, that the Woodwardian Museum has been enriched with 
300 species of Invertebrata, and a multitude of Fishes, Reptiles, 
and Birds; among the latter being Paleocolymbus Barretti, Pela- 
gornis Sedgwicki, and nine species of Pterodactyle, which are not 
Reptiles, but form a class of Aves called Saurornia. 
A little north, in the Ely pit, the Upper Greensand rests on an 
ash-grey clay, which is the Gault (e), not more than 20 feet thick. 
It extends in a curve from the base ofthe section on the south to 
its top on the north ; but the upper part is denuded, and the lower 
part is concealed with drift. In it are scattered spherical nodules 
of phosphate of lime, two or three inches in diameter, but unlike 
those of the Greensand in not being rolled. There nowhere is seen 
that passage from Gault to Greensand which there is from Green 
sand to Chalk ; but the sections show no unconformability. 
Accustomed to associate phosphatic nodules with numerous ver- 
tebrate remains, their presence here, asin the Hunstanton Red Rock, 
seems unnatural. But neither here nor in the Greensand are the 
nodules coprolitic. They are in all cases rolled shore accumulations 
or concretions. The Apatites of Europe and America show no 
evidence of animal origin; on the contrary, one in Bavaria con- 
tains Jodine, 1 substance eminently vegetable. And as Zostera 
and many sea-plants contain a notable per-centage of phosphate of 
lime, it is not impossible that shore plants, and plants growing over 
submerged lands, as the Gulf-weed Sargassum, may by decomposition ~ 
