on Strathearn. 365 
it continued its channel, with little variation from a straight line, 
nearly due east, running along the tract of the Powaflery river, 
now a retrograde stream, over the valley where moulder the rains 
of the abbey of Inchaffery; and, holding the same line, passed 
below the House of Balgowan, aid the Castle of Methven, until 
it joined tie water of Almond at Pitcairn Green, at that period 
probably an arm of the sea, which then certainly covered large 
portions of the flat land along the bauks of the Tay near Perth. 
Over the whole of this ground undoubted proofs of the effects of 
water are evident, by an examination of the debris collected at 
different times, eave form a variety of strata, and contain boul- 
der stones of many species, brought from the mountains by suc- 
cessive floods and inundations of the river. 
But, after the river had ceased to flow by the course which it 
has thus been supposed primarily to have taken, the valley of 
Strathearn seems to have undergone other considerable revolu- 
tions from the changes of its river. 
We have said that Lochearn, according to its original ex- 
panse, formed a lake, from its western extremity to the House 
ef Ochtertyre, of twenty miles long, but of irregular breadth. 
The catastrophe which diminished » it to the present size, and 
eave the river a new direction, does not seem inexplicable. It 
is the opinion of many profound geologists, that the western 
_ mainland of Scotland, with its numerous islands and promon- 
tories, were anciently ‘united, forming a compact and undivided 
continent; but that, by entendous. convulsions, produced by 
general as well as by | partial earthquakes, a disjunction of the 
primary structure was effected, and occasioned that separation 
of islands from the mainland, and on the mainland, that asto- 
nishing irregularity of coast, so indented with arms of the sea, 
which renders its navigation. so intricate, but gives to the mine- 
ralogist an ample field of research, and to the painter an admi- 
rable display of sublime scenery.—To the cause that has produced 
such wonderful phenomena do we also attribute the reduction 
of ancient Lochearn. 
The departure of the river from the great level plain of Dal- 
ginross, the former bottom of the lake, is through a narrow 
chasm, the sides of which appear at one time to have been united, 
as they are composed of the same materials, and were disjoined 
by some of those convulsions of the earth, which, even of late 
years, have been so common in that vicinity. This disunion must 
have been sudden, though from the very remote period at which 
we may believe it took place, no calamitous consequences as to 
human life could have happened, as the kingdom was probably 
not inhabited for many subsequent ages. By the sudden sepa- 
ration of this hill, the north side of which was washed by the 
lake, 
