Seeley— On the Cretaceous Beds at Ely.’ 531 
have supplied the phosphoric acid now stored up in the Cretaceous 
strata. 
So full of pounded and rolled shell-fragments is the Gault in this 
Ely Section that it looks as though it might represent the entire 
Gault period. There are multitudes of compressed Perne in every 
block ; the species is Perna concentrica and its varieties. Here 
also are found Belemnites minimus and B. attenuatus, Ammonites 
proboscideus and A. auritus, Perna sulcata, Nucula pectinata, &c. &c. 
The Gault is also fossiliferous at Haddenham, where it was first 
found by my late friend Lucas Barrett, who collected from it Hda- 
phodus Sedqwichi. 
Approaching Cambridge it thickens to 150 feet, and the upper part 
becomes unfossiliferous, only yielding to years of search a small 
Ichthyosaur, a Siluroid fish-spine, Ammonites splendens, Plicatula 
pectinata, and a few spines of Diadema. 
Jt generally may be recognised by the flatness of its surface and 
the course of streamlets along it. 
The Gault (e) is seen to rest on a brown ferruginous sand rock, 
which is the Shanklin Sands (f). This deposit, too, has by disloca- 
tion been bent into a curve, and in several places the rock has 
snapped, and there are breaks of several feet, into which the Gault 
has been squeezed so as to look as though deposited on the Kimme- 
ridge Clay. All the beds have been roughly handled, and in places 
the older clay has been squeezed into slight folds under the Shanklin 
Sands. : 
The lower part of the Shanklin Sands is a conglomerate of small 
rounded pebbles, which in the best place in the section is hardly 
more than four feet thick, and above this are some brown sands 
alternating irregularly with thin courses of clay with phosphatic 
nodules ; and in places these deposits almost stand on end through 
false bedding. ‘They are seven feet thick, and unfossiliferous, a good 
deal resembling the beds below ; but I cannot say they should not be 
classed with the Gault. <A rolled fragment or two of Ammonites 
biplex is the only fossil I have found in the rock ; so that it might 
be Portland Sands but that it is traced to Hunstanton, where fossils 
are more numerous. It caps the Ely Hill, and to judge by the city 
walls was at one time largely quarried. Other outliers of it are seen 
at Haddenham, where it is twenty feet thick, and at Cottenham; 
though I failed to find it at Denny Abbey. About five miles NW. 
of Cambridge it crosses the Roman road and forms a bright brown 
strip in the fields: here, at Oakington, it has yielded a large Pano- 
_ pea. It is well seen again at Great Gransden, showing an unusual 
amount of false bedding. And near by at Caxton a well was sunk 
through twelve feet of Boulder-clay to Shankin Sands, which gave 
the section— 
Ironstone Clinkers, 14 feet ; 
Ferruginous Sand, 104 feet ; 
Bright-green Sand, 3 feet. 
Plenty of water coming in, the latter bed was not pierced. At 
Bourn, the sand, which is full of bands of clinkers, contains much 
M M 2 
