A HISTORY OF CUMBERLAND 
It should be again mentioned here that the land surface upon which 
the old screes and desert sands were laid down was very irregular. One 
of the chief depressions lay between where Appleby and Armathwaite 
are now—though the reader must guard himself against supposing that 
the depression referred to bore the slightest relation to the inequalities of 
the present surface. It was on the eastern slopes of this hollow that the 
chief deposit of the old screes took place. It is this which now forms 
the Brockrams of Edenside and Whitehaven. In the deeper part of the 
hollow little else than wind-blown sands were swept, and it is from these 
that, as already mentioned, the Penrith Sandstone has been formed. The 
depression must have exceeded 1,200 feet in depth. 
(7) Some time after this hollow had been nearly filled up by the 
old screes and desert sands, one of the great terrestrial undulations to 
which the elevations and depressions of the land are due gradually 
reached the site of Cumberland. The sea gradually approached, the 
climate ameliorated, rain fell regularly, and vegetation of a different kind, 
chiefly allied to the Cycads and some primitive types of Conifers, began 
to spring up. Under these conditions the character of the strata that 
were deposited changed by slow degrees, and sandstones and clays of 
almost normal character were laid down. It is these which form the 
well-known Plant Beds, which, although best developed near Appleby, 
are also found within the Cumberland boundary (Desert Conditions, p. 
218). 
(e) As the wave of depression slowly passed over the land, the sea 
once more gained admittance. It was probably never very deep here 
under these conditions, but to the east its depth was greater, and a thick 
mass of limestone, which was originally not very different in its character 
from the Mountain Limestone, was gradually formed. The fossils it 
contains inform us that the descendants of the Invertebrate animals 
which peopled the Carboniferous seas had not changed very much from 
the form of their ancestors. Some had died out, and some new forms 
had come in from other areas ; but as most of them consist of lowly 
forms of life, which are least prone to change, the assemblage as a 
whole reminds one very much of what we meet with in the limestone 
which preceded it. This later limestone is called the Magnesian Lime- 
stone. In the upper part of the basin of the Eden it is about thirty feet 
thick, but that thickness lessens as we trace it north-westward, and in 
many places in Cumberland it may never have been deposited at all. It 
is well seen on the shore south of Whitehaven, where it yields fossils 
which tell us plainly of its marine origin. 
North Cumberland was apparently not submerged at this period, 
so that it is more than likely that some of the strange uncouth reptilians 
may have wandered there on the seaward margin of the old land, while 
marine animals were living in the sea only a few miles further south. 
If we measure geological episodes by centuries, the period required 
for the formation of the Magnesian Limestone must have been one of 
great length, for there is little reason for regarding it as having been 
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