468 PROCEEDINGS OF SECTION C. 
Town. I believe I am right in assigning the position which the 
three last-mentioned coal-measures occupy, in the lower levels, to 
seismic depression of the surface of the area which they occupy, 
long after the deposits were formed, for the reason that they are 
intimately associated with eruptive and disrupted basalts corres- 
ponding to the older or Miocene basalts of Victoria. 
The principal coal-beds of Tasmania, from a commercial point 
of view, are those at Mount Nicholas, in the district of Fingal, 
Mount Ben Lomond, 30 miles distant easterly, and at the Sandfly 
Rivulet Ranges, in the Huon River district, south of the island. 
These all occupy elevated positions on the sides of mountain 
ranges, the altitude of which vary from 500 feet to 1500 feet above 
sea level. These coal-seams, with their associated interstratifying 
clay-shales and sandstone, present a nearly horizontal position, 
the average inclination, or dip, being 24 deg. north-east, while 
the Upper Silurian strata on which they repose uncomformably, 
and which chiefly consist of purple and yellowish variegated 
arenaceous incoherent shales, with intercalating slates, have an 
average inclination of 70 deg. The Mount Nicholas coal-seams 
may be accepted as a type of these alpine coal-measures in the 
island of Tasmania. The summit of this range consists of crystal- 
line diabasic prismatic greenstone, its greatest altitude being 
1800 feet above sea level, or 1000 feet above the Break-o’-Day 
valley. The uppermost coal seam (which is that mined by the 
Cornwall Coal Mining Company, and exported to Victoria) has a 
thickness of 11 feet, but at the western extremity of the range, 
distant about two lineal miles, it attains a thickness of 15 feet in 
the clear. There are known to me five other different seams, vary- 
ing from two feet in thickness to five feet. They are all bituminous 
coal, of a dense, laminated structure, possessing a well-defined 
cleavage conformable to the line of deposit. The coal-seams 
which obtain on the southern side of the range have their exact 
equivalents on the northern side. They have been cut through 
in the depressions at both ends of the mountain range. That 
they have not been subjected to any displacement, such as would 
be the result of telluric disturbance since they were deposited, is to 
be gathered from the fact that they only depart from the horizontal 
position by a mean dip of 6 deg. east by south on both sides of 
the range. All the associated strata of clay-shales, sandstones, 
marine mudstones, and limestones—the faunal paleontology of the 
two latter formations being striking analogues of the faunal 
paleontology of the carboniferous, z.c., mountain limestone of 
Europe—are conformable to the coal-seams. The base of the 
system is a coarse, pebbly conglomerate, reposing immediately 
upon the edges of the upturned Upper Silurian shales and sand- 
stones. In brief, these coal-measure strata, at one remote period, 
formed an unbroken zone, or belt, around these older greenstone 
heights to within, on an average, 500 feet of their summits, as 
