417 



rieties. From this fact, as also from the exact similarity of position 1 

 which they occupy in the mine, the differences in different varieties 

 of coal are ascribed to original difference in the plants from which 

 they were derived. 



The author next adverts to the escape of inflammable gas from 

 coal, and cites various interesting facts, principally from the authority 

 of Sir H. Davy and Mr. Buddie, in proof of the existence of inflam- 

 mable gas ready formed in coal while contained in the mine ; of the 

 immense quantity which is sometimes emitted by blowers, indicating 

 a free communication between the reservoirs in which it resides j and 

 of the great pressure to which it is there subject. He ingeniously 

 shows the probability of the gas existing within the coal in so com- 

 pressed a state as to be liquid. A consideration of these circumstances 

 induced the author, while engaged in his microscopic inquiries, to 

 search for a structure in coal capable of containing gas ; and he 

 accordingly discovered a system of cells, different from any before 

 mentioned, and apparently adapted for that purpose. These supposed 

 gas cells are found empty, are generally of a circular form, occur in 

 groups which communicate with each other, and each cavity has in its 

 centre a small pellet of carbonaceous matter. The author establishes 

 a clear distinction between these gas cells and those above described 

 as being filled with bituminous matter ; for the anthracite of South 

 Wales contains the former, but is quite free from the latter. He also 

 states, on the authority of Mr. F. Foster, that the anthracite of South 

 Wales affords a free disengagement of inflammable gas when first 

 exposed to the air. 



A communication " On Ophiura found at Child's Hill, to the N.W. 

 of Hampstead," by Nathaniel Thomas Wetherell, Esq. F.G.S. was 

 then read. 



After noticing the rare occurrence of Ophiura, and that in England 

 they had hitherto been observed only in the chalk and the lower di- 

 vision of the oolitic series, the author states, that he discovered, in 

 1829, several specimens of a species of Ophiura in the septaria of the 

 London clay of Child's Hill ; that they were associated with some of 

 the most characteristic shells of that formation ; and that he had 

 found fragments of the same Ophiura in a septarium from the High- 

 gate Archway. 



Jan. 23. — Herman Merivale, Esq. of Woburn Place, Russell 

 Square 5 the Rev. Robert Hankinson, of Bilney Lodge, Lynn ; and 

 Charles Atticus Monck, Esq. of the Coldstream Guards ; were elect- 

 ed Fellows of this Society. 



A Geological Memoir was read " On a portion of Dukhun, East 

 Indies," by Lieut.-Col. W. H. Sykes, F.G.S. F.L.S. &c. 



The author describes his track as bounded on the west by the range 

 of mountains usually called the Ghauts by Europeans, from a mis- 

 conception of the term Ghaut, which simply means a pass, the proper 

 name being the Syhadree ; on the north by the Mool river, on the 

 east by the Seena river ; on the south by a line drawn from the city 

 of Beejapoor to the town of Meeruj, continued up the Krishna and 

 Quina rivers to the hill fort of Wassota in the Ghauts ; comprising 



