100 Mr. H. Seeley on Cambridge Geology : — 



in a ditch, it was found to be yellowish white, more sandy, and 

 almost free from oolitic particles. The fossils here were few, but, 

 under the slightly altered conditions, differed a little from those 

 met with in other places. In general they are very similar to 

 those of the inferior deposit, though including some forms which, 

 so far as yet explored, have served to distinguish it. 



This thickness of about 14 feet appears here to form the en- 

 tire mass of this peculiar rock. And yet, in tracing the brook 

 to the south, I found in its bed three successive layers of a hard 

 whitish-grey rock, of 6 or 8 inches in thickness, occurring in 

 the clay at heights above the rock of Elsworth of about 7, 15, 

 and 20 feet. However, these only contain a few Gnjphcea dila- 

 tata, and resemble more than anything else layers of hard, dark 

 Lower Chalk. There is nothing to suggest any connexion with 

 the Inferior beds ; but it is just possible that they represent the 

 extreme limits of strata which may elsewhere thicken and unite 

 with them. The dip to the south seems to be about one foot in 

 two hundred. 



Having become thus far familiar with the exhibition of the 

 rock about Elsworth, I endeavoured to discover whether it were 

 merely local, or a regular stratum which might serve as a boun- 

 dary between great thicknesses of clay. 



From the great accumulation of the clay, sinking for water 

 here is scarcely more profitable than sinking for coal would be ; 

 and therefore in the small neighbouring villages there are few 

 deep wells. However, some have been attempted. One of these 

 was at a point rather more than three miles S.S.W. of Elsworth, 

 and sunk to the depth of 150 feet. They dug through 84 feet 

 of a hard dark-blue clay, from which many Ammonites were 

 obtained ; but, as the well was made thirty-six years ago, these 

 are not now to be heard of. Below this they came upon 14 feet 

 of alternate bands of stone and sand (the stone was full of 

 small shells), and an extremely hard grey-blue rock, which they 

 had to get up with chisels and blacksmith's hammers, working 

 for six months before they got through it. 



The dip of the Elsworth rock has already been given as one 

 foot in two hundred, and the distance of this digging from 

 Elsworth as about 16,000 feet; therefore, if the rock extended 

 continuously, and preserved the same angle of dip, it ought to 

 be found, at this distance, at a depth of 80 feet ; and so, when 

 a rock is found there, at that depth, of a thickness, hardness, 

 and appearance identical with that of Elsworth, I must urge 

 that the evidence approaches the conclusion that in both places 

 the rock is one and the same. In Papworth Everard, a village 

 a mile and a half to the west of Elsworth, a rock was met with 

 in a well-sinking at a depth of 7 feet, but not pierced. Papworth 



