44 A RECENT VISIT TO THE DALMATIAN COAST. 
gradually cooling and shrinking interior portions. This trough has 
one of its complementary crests or anticlines to the northwards in 
the parallel ridge of high land which runs through central Europe 
and western Asia, a ridge which, although it has undergone many 
and great changes of level, has in the main always retained an 
elevation high in comparison with its corresponding trough to 
the south. Farther to the south another crest belonging to this 
same system of folding is visible in the Atlas range. 
This primary system of folding or rucking up of the earth’s 
surface, which is still recognizable when the phenomena are 
studied on a large scale, must have originated in remote 
Paleozoic times, but its pristine simplicity, as might be 
expected, has been much modified and altered by subsequent 
earth movements. These subsequent movements can be resolved 
into two systems, acting in directions almost at right angles to 
each other; that system of movements running in the original 
east and west direction resulting in the elevation of the present 
Alps, and the Pyrenees and the Cantabrian Mountains, with the 
parallel ranges of Spain to the south; whilst the movements 
acting at right angles or in a meridional direction have resulted in 
the elevation of the Apennines and Dinaric Alps, and the moun- 
tains of Albania and Greece. 
These cross movements, acting in a direction approximately 
north and south, were also due to tangential thrusts resulting 
in folding, the sea for the most part occupying the hollows 
between two successive crests or anticlines of the fold. This 
is nowhere seen better than in the Adriatic, which lies in a great 
sag or syncline, two anticlinal phases of the fold being represented 
by the Apennines on the west, and the mountains of Dalmatia 
and Albania on the east. 
Another effect of this later folding in a meridional direction, 
which only took place in Tertiary times, is very evident when we 
come to examine a hydrographical map of the Mediterranean 
shewing the various depths of the sea. Instead of one trough or 
basin of uniform depth, there are recognizable four distinct areas 
of deep water separated by ridges running approximately north and 
=" 
