CV111 PROCEEDINGS—PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
to rise up, somewhat suddenly, about a dozen miles off. Their line 
is broken by several small glens trending down towards the plain 
in front, and behind them rise the blue ridges of the higher Perthshire 
Grampians. In the foreground of this view is the River Tay, wend¬ 
ing over the alluvial haughlands of which the site of Perth forms 
a part, and then turning sharply to the east, after sweeping round 
the lower end of Moncreiffe Island. Next, looking more to the east, 
we see the crags of Kinnoull Hill, with their dark precipitous rocks 
and tree-covered slopes below, and forming, with the Tay winding 
through the carselands, one of the loveliest bits of river scenery to be 
seen anywhere. Lastly, we turn to the south, and there we see the 
extraordinarily broad extent of flat haughland built up by the River 
Earn, and suggesting the idea of a lake more than of a valley floor. 
Beyond this plain rise the green and rounded slopes of the Ochils, 
which form so complete a contrast in form and tint to the range we 
have just seen to the north. 
Such is the scene which meets our eye to-day; let us try to 
picture to ourselves some of the scenes which stretched themselves 
out while each successive feature in the present landscape began to 
take form. To take the oldest features first,—the Grampians on our 
northern horizon carry us right back, at one bound, to some of the 
earliest chapters in the world’s history, to an antiquity so remote that 
its memorials have lost almost all trace of their original form. Still 
we know that for ages, while these hills were being formed, a great 
sea rolled where we now stand, stretching probably over the greater 
part of northern Europe. Not very far distant, however, were the 
shores of some primeval land, from the waste of which sand and mud 
were swept down into our ocean. At one time it was pure white 
sand of pounded quartz that was laid down, at another time silvery 
flakes of mica covered the ocean floor, and again dark ooze-like mud 
was deposited. The conditions did not always remain the same, for 
sometimes the land rose, and gravel and coarse sand were scattered 
round its fringes. At other times it sunk to greater depths, where 
only the finest layers of clay were deposited. Signs of life were 
present in that ocean, but only in its lowest forms. In the deeper 
parts the flinty and limey skeletons of microscopic creatures sank to 
the bottom, and through countless years built up the layers of lime 
and silica that we now find as beds of limestone and chert; while in 
the shallower parts lowly forms of sea-worms burrowed in the sand, 
and left the impress of their tracks to be discovered in after ages on 
the tops of some of our highest hills. 
Leaving this primeval ocean, our second scene brings us to 
a period much more recent, though still in the earlier chapters of 
geological history. The Highland hills have now emerged from the 
ocean in which they had their birth. Their flanks, running as at 
present in a pretty straight line from north-east to south-west, slope 
down into a wide and shallow sea, stretching away on either hand 
as far as the eye can reach. The hills are much vaster than at 
present, and their sides are furrowed by torrents which bring down 
sand and shingle from their slopes, the latter to be picked up along 
the rocky shore, while the finer material is carried by the currents 
