05 
the pillars of Fingal’s Cavo are 18 feet in altitude, while tljose 
of Garabh Eilan are 499 ! 
llie Liassic rocks of this island first appear in a skerry-like 
ridge of half-submerged rocks on the north-east shore ; rising 
■with a gentle dip out of the ivaters they ascend into a low 
clifl, and cut through a projecting tongue. They consist of a 
lower bed of indurated clay slate, and an upper one which is 
converted almost into porcelain jasper. 
Tlie locality is one of much mineralogical interest, as that at 
which Dr. I’atrick Neill first discovered WavelUte in Scotland ; 
and, with the exception of a single specimen found by the 
writer in (Jloncoo, it is still the only Scottish locality for 
the mineral. It occurs in general in dead-white llattened spheres 
of radiating crystals ^ these spheres are over half-an-iiich in 
diameter. Occasionally it is lustrous and transparent. 'J'ho 
llattened spheres line cmcks in the rocks; this freipiently 
has assumed a globular structure which is duo to its beiiif' 
permeated with radiating and spherical groups of crystals of 
the mineral. Analcime in weathered specimens was also found ; 
as also a crystal or two of indilTorent Siilbife. ^Massive Mesolite 
also occurs, both here and filling the jointings of the basaltic pillars. 
hero this schist is seen on the south side of the prolonged 
eastern promontory of Garabh Eilan, it exhibits singular oval 
cavities lined with a coating a quarter of an inch in thickness 
of a material which has been set aside for analysis. Those cavities 
have much more the appearance of being duo to the former 
presence of organisms than of being druses. 
The writer having been unable to land upon Eilan Whirrj-, can 
only say of it that there is evidently a greater amount of the 
sedimentary rock there than occurs on Garabh Eilan, and that it 
seems in certain parts to bo much dislocated and fractured. 
Of the Dolerite, which forms the pillars of these islands it 
has to bo noted that it frequently shows the same radiated 
structure which has been stated to occur in the schist. 
The Glaciation of the Island. There may bo said to be 
at present i/iree theories as to the glaciation of the north of 
Britain. 
First, that which maintains that a great sheet of ice, of 
2500 or 3000 feet in thickness, swept across the North 'sea 
VOL. III. 
F 
