GEOLOGY 
effect of this movement in the course of time was to ridge up the sea 
bottom by slow degrees until, from shallow water, it passed into land. 
The immediate effect was to bring about the waste and destruction of 
the newly-exposed sediments by the combined action of the waves and 
the subaerial waste brought about by rain and the agents working with 
it. There are several facts connected with the behaviour of the rocks in 
the district on each side of the present Bassenthwaite Water which seem 
to indicate that the local upheaval referred to was one of a series, which 
commenced at an early stage in the history of the rocks there, and was 
continued intermittently, while a considerable subsidence was in progress 
in the area to the south. But the full discussion of this matter is of too 
technical a nature to be treated in an article like the present one. These 
local upheavals were intimately connected with the evolution of an im- 
portant group of volcanoes which finally grew up so as to extend over 
a large part of Cumberland, and to which attention will be more fully 
directed further on. 
(d) Leaving for the present the consideration of the events which 
followed the advent of these volcanic conditions we may notice here the 
more prominent features connected with the life of the period. Records 
of the vegetable life of the period are too scanty to enable us to form any 
very clear notion of what it was like ; but such fragments as are known 
suggest that the more lowly forms of vegetation, little higher in grade 
than the seaweeds, were predominant. Of animal life more is known. 
It seems from the available evidence that nothing approaching vertebrate 
forms of life had yet come into existence ; and that, in the sea, at any rate, 
the most highly organized beings were creatures more or less closely 
allied to the Nautilus. On the fine mud which formed the sea bottom 
there certainly lived a considerable variety of the curious jointed-legged 
creatures which are known as Trilobites, from the characteristic three- 
fold arrangement of their larger parts. These in some respects find their 
nearest allies at the present day in the King Crab (Limulus), and perhaps 
also in the Spiders and Scorpions. Remains of Trilobites are occasion- 
ally found on various platforms in the Skiddaw Slates. The writer of this 
chapter figured in the Proceedings of the Geologists’ Association, ix. No. 7, 
all that were known at that time. With these Arthropods lived some 
few lowly forms of Crustacea ; and there were also some representatives 
of the important group of Brachiopoda, which are animals distantly allied 
on the one hand to the Worms, and on the other to the Mollusca. But 
the best known fossils from the Skiddaw Slates are those remarkable 
zoophytes which are known collectively as Graptolites. These animals 
were, in many respects, not very different from the Sea Firs of the pre- 
sent day ; and, like those so-called ‘ seaweeds,’ lived at the sea bottom in 
little colonies, sometimes attached to some stony object, but more often 
anchored to the mud by means of a special arrangement with which they 
are provided for that purpose. Both geologically and zoologically these 
obscure organisms are objects of considerable importance. Those from 
the Skiddaw Slates have lately been described in an important paper 
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