16 The Geology of Cambridgeshire 



Upware sections. These are of two types, Coralline Oolite 

 and Coral Rag. Of these the Oolite is in general supposed to 

 underlie the Rag, but in the now closed pit near the Inn 

 Mr Wedd found rock of the Rag type resting directly on 

 Elsworth Rock, and though each has its own distinctive fauna, 

 it is conceivable that here the order is not invariable, the 

 faunistic assemblage being merely a question of habitat. 



The two exposures termed the North and the South pits 

 have long been known. The North pit is now almost entirely 

 overgrown, but the South pit has been so extended that 

 practically all that was ever seen in the North pit can now 

 be observed in its walls and floor, and a trip to Upware is still 

 one of the most instructive and enjoyable excursions that one 

 can make from Cambridge. 



The South pit is about a quarter of a mile north of the 

 Inn and is about two hundred yards long. The beds dip at 

 about five degrees to the north and hence the lowest beds 

 exposed occur in the south corner of the pit. In 1901 a trial 

 hole and boring was put down near this corner. The first 

 four feet was dug, and pisolitic rock similar in all respects to 

 that of the quarry floor was passed through At four feet 

 a hard bed, very like the Coral Rag of the other end of the 

 quarry, was met with, and when the first layer of this was 

 broken through, so much water sprang up that digging had to 

 be abandoned. A long bar was therefore obtained and a 

 boring made. This broke through several layers of coral 

 rock, intermediate marly beds and iron-stained rubble; and, 

 at a depth of nine feet, came to a very hard rock containing 

 iron-shot oolitic grains. This rock is believed to be the 

 Elsworth rock. 



From the pisolite of the dug portion of the pit, Gryphaea 

 dilatata, many Cidaris spines, and a Collyrites were collected. 

 These were associated with the ordinary fossils of the Coralline 

 Oolite. 



The Oolite is exposed over about three-quarters of the 

 length of the pit and passes gradually up into the Rag. 



