A HISTORY OF CUMBERLAND 
These afford a most important insight into the history of Cumberland 
during the remote period under consideration. The nature of some of 
these rocks clearly points to the presence of geographical conditions in 
which sediments of marine origin were deposited alternately with layers 
of the fine dust which had been transported seawards by the winds 
during some of the more violent eruptions of the old volcanoes, but at 
too great a distance to be reached by the lava streams. That these 
alternations of old marine sediments, fine tuffs, and mixtures of both, 
are contemporaneous with the volcanic rocks in the heart of the Lake 
district, is shown in the most unmistakable manner by the fossils which 
they contain. Their general nature indicates quiet deposition on a 
steadily subsiding ocean floor at no great distance from a group of vol- 
canoes. As it is often convenient to employ some definite name for the 
larger subdivisions of a great pile of rocks like these, taken from the 
locality where the rocks are now best seen, the present author several 
years ago proposed for these sedimentary equivalents of the volcanic 
series the name of the Milburn Rocks. They are well seen below Cross 
Fell, and they are particularly well exposed in John Robinson’s Pastures, 
on the north side of the village of Milburn: whence the name. Their 
aggregate thickness cannot be made out with certainty, but it can hardly 
be less than between 5,000 and 6,000 feet. The principal fossils are 
Graptolites, Trilobites and Brachiopoda, all of Lower Llandeilo types. 
The fact that we have perfectly clear evidence of marine conditions 
and of continued subsidence within twenty miles of the centre of the 
volcano would prepare us for the idea that the later stages of volcanic 
activity coincided with a subsidence at least of part of the volcanic area 
itself. And, further, the facts quite justify us in regarding the volcano 
as one which was only enabled to keep its summit above the waves by 
the fact that the eruptions piled up the volcanic material at a rate 
which, on the whole, kept pace with the rate of lowering of the sea floor 
until at least the later stages in the history of the volcano. 
(c) Volcanic areas usually coincide with areas of unequal sub- 
sidence, and that of Cumberland appears to have been no exception to 
the general rule. Some of the geological facts which may be observed 
in the areas around Bassenthwaite seem to point to the conclusion 
already referred to, that this area did not sink at the same rate as the 
area around where Ambleside is now. There may even have been some 
upheaval in the northern part while subsidence was going on in the 
south. To put this statement into another form, we may say that, while 
the southern end of the area sank as fast as the volcanic material was 
piled upon it, the northern end either remained stationary or else was 
slowly ridged up from the sea bottom, and thus was wasted by the 
weather and the sea almost as fast as it rose. The idea is not easy to 
grasp, and would not need to be again referred to here if the fact had 
not an important bearing upon some events of later date to which 
subsequent reference will be made. 
(¢@) There is some doubt as to the exact nature of the events which 
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