COMBUSTIBLE MINERALS, NOT GASEOUS. 
191 
face of the ledge. On making an excavation, the coal widened to twenty-two inches ; but it 
then diminished to a narrow seam, and the working was abandoned. This locality was about 
a thousand feet above the Hudson. The coal is said to be light and shining, and it burns 
with a moderate flame. Other veins of a similar kind have been noticed in the same range.* 
LIGNITE. 
[From the Latin lignuvi, wood; in allusion to its origin.] 
Lignite. Cleaveland and Beudant. — Wood Coal. Thomson. 
Description. This mineral, which is often described as a variety of coal, still differs con¬ 
siderably from it. All its varieties have undoubtedly originated from wood, and the process 
of change has probably taken place at a period not very remote. In most cases the texture 
of the wood is preserved, and it burns exactly as wood does, leaving a residue of ashes, but 
often more abundant. 
The odour which lignite exhales is different from that of burning coal or bitumen. It is 
usually unpleasant, sometimes sharp or fetid. It also differs from coal, in yielding, when 
subjected to distillation, a peculiar acid liquor. 
Varieties. Jet. This is deep black, opaque, and so solid and hard that it may be turned 
on a lathe. Fracture conchoidal. Lustre resinous. 
Brittle Lignite. Differs from jet, by its great brittleness. Colour black, with a shade of 
brown. It is less shining than jet. The surface is easily divisible into cubical or trapezoidal 
fragments. 
Bituminous Wood. This is made up of the roots, branches or trunks of trees, usually 
somewhat compressed. Texture ligneous, with little lustre. Colour brown, or brownish 
black. 
Composition. Carbon 71.71, hydrogen 4.85, oxygen and nitrogen 21.67, ashes 1.77 
{Richardson and Regnault). 
Geological Situation. Lignite is usually found in the more recent formations. When 
in suflicient abundance, it is converted to the same uses as coal and anthracite; but this is 
seldom the case. 
localities. 
Richmond County. Near Rossville is a stratum of lignite from three to six inches thick, 
near or below high water mark. Sometimes the mineral has the colour and appearance of 
wood slightly charred ; at others, it is quite compact, has a dark brown or nearly black colour, 
and resembles jet. Crystals of iron pyrites occur in the fissures of the lignite, and these are 
J. Pierce. American Journal of Science, VI. 86. 
