320 ON THE EXPOSED STKATA OF THE OXFOKD SEWAGE-FARM. 



At trial-hole no. 4 (fig. 10) this gravel is composed almost entirely 

 of small oyster-shells derived from the marl. The peat here is 

 covered with a superficial clay, probably brought down by atmo- 

 spheric denudation from the Kimmeridge Clay on the hill near by. 



It is hoped that these notes may not be altogether without in- 

 terest, as they may preserve some account of the various sections 

 exposed in the laying-out of the Oxford sewage-farm, which have 

 since been covered up, and are not likely to be again accessible. 



Discussion. 



The President said the paper was an exceedingly interesting and 

 useful one, as placing on record what had been done. 



Prof. Prestwich said the area, though small, was extremely in- 

 teresting, as the sections differed so much from those of Headington 

 and Cumnor. The evidence, however, was perhaps too small to 

 found a theory upon. 



Mr. HuDLESTON said that clay was not unfrequently mixed with 

 the Coral Rag. Probably that clay might come from the source 

 which supplied the clays of the contemporaneous portions of the 

 great Pelolithic formation of the Penland. 



Prof. Seelet said that north of Oxford the Coral Rag became 

 split up into clays ; the fossils changed with this. 



The President said the specimen obtained of Hemipedina mar- 

 chamensis, and also some of the other fossils were remarkably fine. 

 As the sections were closed, such a record of the facts observed as 

 was furnished by this paper was of much importance. 



