172 



Bulletin 35 



320 



Antigua the Central Plain intervenes between the two parts, 

 while in Guadelupe they are only separated by a narrow channel. 

 In support of this proposition the physical features of Antigua 

 are discussed, and it is shown that the island has not been sub- 

 merged since the volcanic period. 



The position and age of the Scotland series of Barbados are 

 then discussed, and that series is shown to be Eocene, the lower 

 beds being possibly cretaceous and being a remnant of the Atlan- 

 tis Continent. 



Page 2S 



The extension, age and position of the Orbitoides bed of 

 Trinidad are next dealt with, and some further remarks are add- 

 ed on the physical history of the Caribean Region. 



In my second "Note on the Manjak Mine" I have given a 

 brief summary of our knowledge of the origin of asphaltic and 

 petroleum deposits. I thought this should have a more extend- 

 ed publicity, and accordingly included it in my paper just men- 

 tioned. In connection with this I may notice the recent upheav- 

 al of a mudbank on the South coast of Trinidad. As Dr. Fred- 

 holm has given an account in the Mirror newspaper of the causes 

 of this phenomenon I will merely add that in all essential fea- 

 tures it is similar to the mud-lumps of the Mississippi River. 

 These have been fully described by Lyell in the "Principles of 

 Geology" (tenth edition 1867) Vol. I., p. 447. His description 

 is the best and fullest, but as that of Geikie (Text Book of Geol- 

 ogy 1882, p. 386) is the most condensed I quote it : "A singular 

 feature of the Mississippi Bars is the formation upon them of 

 mud-lumps. These are masses of clay varying in size from mere 

 protuberances, like tree trunks, up to islands several acres in ex- 

 tent. They rise suddenly and attain heights of three to ten, 

 sometimes even eighteen, feet above the sea level. Salt springs 

 emitting inflammable gas rise upon them. After the lapse of a 

 considerable time the springs cease to emit gas and the lumps are 

 worn away by the currents of the river and the gulf. The origin 

 of these excrescences has been attributed to the generation of car- 

 buretted hydrogen by the decomposing vegetable matter in the 



