ROYAL BOTANIC GARDENS, KEW. 



BULLETIN 



OF 



MISCELLANEOUS INFORMATION. 



No. 5.] 



[1907 



XXVIII -N'HANGELLITE AND COORONGITE. 



L. A. Boodle. 



ago 



found in Portuguese East Africa and described as elastic bitumen* 

 was forwarded to Kew by Sir Boverton Redwood, D.Sc, M.I.M.E., 

 who supplied the following information as to its mode of 

 occurrence from a report made by Mr. J. Gething Hancock, 



" N'hangellite is an elastic description of bitumen, and may be 



termed a mineral india-rubber. It is dark green in colour, and is 



lighter than water, and has probably been formed in the oxidation 



of petroleum. It is most prevalent in the plain to the north and 



north-west of Lake N'hangella, and to a large extent may be 



described, as far as this neighbourhood is concerned, as peculiar 

 to that locality. 



" The N'hangellite, in occurrence, is generally about half-an- 

 inch in thickness, and lies in patches varying from a few square 

 yards to probably half-an-acre in extent. It is chiefly found in 

 long narrow strips on the surface-anticlines of slightly undulating 

 ground, and gives the impression that it has been washed there 

 by water, having largely the appearance of a high-tide mark. On 

 the other hand, it is occasionally found in small pans, again 

 indicating that it has been taken there by water and remained 

 after the water had subsided. ... I made the most searching 

 enquiries # . . and was informed by many that after the 



gradually 



anee." 



appear 



Specimens of this substance, when examined microscopically, 

 prove to consist of a yellowish matrix, in which are embedded 

 diatoms, sand-grains, and sometimes sponge-spicules, pollen- 

 grains, spores, &c. : but these inclusions are unimportant, forming 



* The word • bitumen '' will be used here in its extended sense 

 1375 Wt87 5/07 D * S 29 28065 



