162 I". 0. BoaworiJi — Birth of an hiand near Trinidad. 



And in another letter from Mr. E. C. Buck, dated January 22, 1912 : 

 "A. sandy beacli of considerable extent has now formed round the 

 island, and the craters have diminished to the ordinary dimensions 

 of the mud volcanoes on land." 



The specimens have been examined by Mr. Beeby Thompson, sen., 

 F.C.S., F.G.S., and by the writer. 



The main bulk of the erupted material is bluish clay mud with an 

 oily smell and quite similar to that produced by neighbouring mud 

 volcanoes. 



The rock fragments consist of sandstone, clay-shale, burnt clay, 

 pyrites, etc. The burnt clay is a hard red ' brick ' like tliat occurring 

 in other localities as mentioned above, but as no bed of such rock 

 is found near here it seems probable that the burning has been 

 performed during this eruption. 



The pyrites is in bright crystals and some of the rock fragments are 

 highly charged with it. There are also aggregations of it forming 

 nuggets several inches across. This mineral is often conspicuous 

 in the ejecta of mud volcanoes, and is interesting in view of the 

 common association of sulphurous waters with petroleum and the 

 frequent presence of sulphur in the oil. 



From the crater were taken some fragments of a fine argillaceous 

 breccia. It is calcareous and contains, besides pyrites, some small 

 shells and Foraminifera. This rock was analysed by Mr. Beeby 

 Thompson, who found in the matrix a high proportion of calcium 

 phosphate and ferrous carbonate. It is in fact a kind of clay 

 ironstone. At the surface no exposure of this bed has been observed. 



It is probable that previous eruptions have occurred on the site of 

 the new island, for it is apparently coincident with a mound on the 

 sea-floor which is shown on the Admiralty charts. Soundings have 

 proved a depth of only 1 fathom at this spot, though it was surrounded 

 by -water 3 fathoms deep. 



The facts which have been described above can leave little room for 

 doubt as to the origin of the new island. 



AnalogouH Events in Borneo and Burma. 



Two similar instances may be cited for comparison which are 

 described by Mr. A. Beeby Thompson in his work on Petroleum 

 Mining — ^ 



"On 21st December, 1897, the disturbance occasioned by an 

 earthquake led to the formation of a great mud volcano beneath the 

 sea off the southern point of the Klias Peninsula of Borneo, when 

 sufficient argillaceous material was ejected to form a new island 

 750 feet long, 420 feet wide, and 20 feet above sea-level. The 

 eruption occurred on the crest of a well-known anticline with steep 

 sides, on which petroleum gas exudations had frequently been observed 

 in other localities, where it crossed the land. 



" Probably one of the greatest mud volcanoes on record was formed 

 off the Burma coast on 15th December, 1907, when sufficient material 

 was ejected to form an island 1,200 feet long, 600 feet wide, and 



1 Petroleum Mining, 1910, pp. 102-3. 



