V 



Correspondence — Dr. J. W. Gregory. 187 



composition closely corresponding to that of the Oceanic Clay of 

 Barbados. 



The recent calcareous ooze closely resembles the more calcareous 

 " chalks " of the Barbadian Oceanic Series, but the latter contained 

 much colloid silica and fine clay. The differences between the 

 analyses of the recent ooze and of English chalk, when certain 

 allowances are made, were found to be but small. The recent 

 calcareous ooze contained many more Globigerina-tests than Tertiary 

 or Mesozoic chalks, but it is suggested that this is due to our 

 possessing only the surface-layers of the Glohigerina-ooze. 



In one important respect all the different kinds of deposit which 

 were examined resembled one another, namely, in the infinitesimally 

 small quantity of quartz which they contained. 



The authors' examination of the recent oceanic deposits, and 

 a comparison of them with the raised Barbadian deposits, only 

 increased their conviction that the latter were of truly oceanic 

 origin. 



LOWER GREENSAND FOSSILS IN KENT. 



Sir, — I am indebted to Messrs. Jukes-Browne, Monckton, and 

 Leighton for calling my attention to an unfortunate omission in 

 Part V. of the paper published in the March Number of the 

 Geological Magazine. The word " Eastern " was omitted from 

 before England in line 22 from top of page 101. Six times on 

 that page it is repeated that attention is being restricted to the 

 area " of Guildford and Dorking," " the line between Guildford 

 and Godstone," " the line between Guildford and Caterham," " the 

 London area or to the south of it," etc. I had never thought of 

 questioning the occurrence of Eoplites interrwptus in Wiltshire or 

 even the West of Surrey. It is recorded from Devizes in the 

 paper of Mr. Jukes-Browne, quoted on the same page; good 

 specimens from that locality are exhibited in the show-cases both at 

 Jermyn Street and in the British Museum (Natural History). That 

 this species as well as the lower Ac. mammillare should reappear to 

 the West of Guildford area, in association with the Lower Green- 

 sand outliers, appeared inevitable. 



Mr. Leighton has sent ine four fragments of an Ammonite from 

 Westcott, which are no doubt referable to Eoplites interruptus. Mr. 

 Leighton has therefore obtained the fossils " from the very base of 

 the Gault in Eastern Surrey," without which, as it is said in the 

 paper, "no final answer to the question discussed in Part V. can 

 be given." Mr. Leighton has fortunately found there a nodule bed 

 at the base of the Gault. It appears to be at the very base. The 

 Ac. mammillare zone is therefore still absent; so that the replacement 

 or tliinning out of the mammillare and interruptus zones in the area 

 of London and to the south of it, has in the Dorking district only 

 affected the former, and not both of them. If the mammillare zone 

 be included with the Gault, as seems now generally agreed, then the 



