Geology 



were here dealing with a fossil ooze of which the globi- 

 gerina ooze is the Recent representative. 



The mineral glauconite has been found to occur in 

 the deposits forming on the ocean floor near the edge of 

 a continental shelf, and it would therefore appear that 

 the Cretaceous rocks (Lower Greensand to Chalk) in 

 our section had been formed under the following con- 

 ditions : the bed of pebbles at the base of the Lower 

 Greensand represents shore conditions, and the Lower 

 Greensand itself, with its glauconite grains and sponge 

 spicules, a greater degree of submergence. The finer 

 sediments of the Gault indicate the mud zone, and the 

 Upper Greensand a temporary return to shallower 

 water, followed by a subsidence of some considerable 

 magnitude during which the chalk was laid down. 



The principal trade of Red River appeared to be in 

 bricks and tiles, but there were also large heaps of 

 alabaster and numerous barrels of plaster of Paris lying 

 upon the wharves. These, we were informed, were 

 brought down by a mineral railway from a factory to 

 the north-east, and by the courtesy of the manager we 

 were allowed to travel in one of the empty waggons 

 returning from the town. 



Arrived at the works, we found an enormous excava- 

 tion in a red clay or marl which dipped towards the 

 south at an angle of 10. At the south side of the 

 excavation the marl was cut off by an east and west 

 fault. Beyond this fault was a red sandstone, which on 

 examination proved to be the same as that which lies 

 beneath the Lower Greensand at the head of the 

 gorge. 



We were told that in a bore-hole put down with the 



116 



