FRANCIS ON COAL DEPOSITS. 
125 
Anniversary Meeting of the Geological Society, 1877.” 
Presented by the President . 
The following communications were read : — - 
I. On a Chemical Examination of Specimens from the 
RECENTLY DISCOVERED COAL DEPOSITS AT WlLLIAMSVILLE 
and Montserrat. By E. Francis, F.C.S. 
1. The Williamsville Mineral. 
The geological conditions under which this mineral occurs 
have been fully described in a paper by the President of this 
Association (On the Discovery of Tertiary Coal at Williams- 
ville, Savanagrande, by B. J. Lechmere Guppy, F.G.S., 
F.L.S., Proc. Scien. Assoc. Trim, 1877, p. 110), at whose 
request the following chemical examination was undertaken, 
and who kindly furnished the necessary specimens. 
In laying the results of the investigation before the meet- 
ing, it must first be mentioned that the assignment of the 
term “coal” to this mineral is incorrect, for although it 
resembles coal in appearance, it proves to be a variety of 
asphalt or bitumen. 
The chief physical characters of the mineral are as fol- 
low : — 
It is very brittle, being easily disintegrated by pressure 
between the fingers. Its fracture is irregular, but somewhat 
laminated, the broken surfaces having a bright and coal-like 
lustre. The fine powder is black, with a reddish tinge. 
Before the blowpipe, it intumesces and burns with a smoky 
flame, leaving a porous fragile cinder difficult to calcine. 
Heated in an open basin, it swells up to many times its bulk, 
forming a porous plastic mass which decomposes and gives 
