08 
upon wliicli tliG silts and limestones of tlie Lias found a resting 
place ; and as in the West of Scotland we hnd the Lias nowhere but 
in association with these igneous rocks, we may safely assign to them 
tlio function of having fitted the waters, in depth and perchance in 
temperature, to the necessities of a Liassic period and life. The 
Liassic land, moreover, may never liave been dry land until during 
the last days of the volcanic agency; there is, at least, strong 
evidence that it was not so at the time of its overllow by the 
molten sheets. Iby land soon comes to bo covered with soil, and 
clothed witli vegetables; when thi.; is overflowed by molten 
matter, the earth is burnt into a rod brick-like clay, termed ijhjn- 
thite. Many successive beds of this are to be seen in Skye, but no 
trace of it appears between the Liassic schists and the birsaltic over- 
llow in the Shiants. Stili, the form of the land leads to the con- 
clusion tliat a sub-aerial crater had Hung the light of its lurid fires 
hailing St. Xihla from afar, Morvern, and the distant !Mull — across 
the Laurentian fringe of the Long Isle-lighting, like a mid-ocean 
I’haros, a narrower and river-like Clinch, and flashing. ruddy from 
the cliffs of lorridon, or with snowy glimmer from the quartzite 
peaks of Loss. 
The Shiants consist of three islands : two, Eilan an Tigh and 
Garabh Eilan, which are connected by a low spit, lie in a north 
and south line ; the third, Eilan Whirry, lies north east of these, 
and landlocks a deep-water cove, which may represent the former 
volcanic throat. 
Ihe material of basalt, obeying the usual law, contracts during 
cooling, and if it bo contact-bound at its extremities, it tears 
Itself into rents and fissures in contracting; if the sheet of molten 
basalt be uniform in thickness, and if it be overlaid by rock of 
such thickness that its cooling must be a slow and regular process, 
these rents pass with singular regularity and persistence from top 
to bottom of the stratum, giving it an appearance and a structuie 
similar to a multitude of pillars : to this structure the teim hasaliic 
has hence been applied. 
Uho southern island, though basaltic in structure, especially 
on its eastern face, docs not exhibit any marked regularity in 
that structure ; but it is from that regularity, or rather the 
surfirce-roughness consequent thereto, that the larger or northern 
island derives its name. Eew things are rougher than an 
