HARDWICKE'S SCIENCE-GOSSIP. 



127 



up at its head. Derwentwater and Bassenthwaite 

 Lake were almost certainly at a former time one 

 long sheet of water ; but the river Greta has de- 

 posited a large delta in its midst, and now the lakes 

 are parted by some three miles of alluvial land. 

 In like manner Buttermere and Crummock Water 

 were formerly one ; but streams from the mountains 

 have brought down their stony freight and formed 

 a delta, dividing the once long lake into two. 

 Most of the Cumberland lakes that I have yet 

 examined seem to be true rock-basins ; that is, they 

 lie in rock-hollows, which have been rounded and 

 scratched on all sides by the old glaciers, leading 

 one to the belief that these hollows, if not actually 

 formed by the scooping power of the ice— as Pro- 

 fessor Ramsay's theory suggests — have at least 

 been deepened by it. 



The terminal moraines of the last set of glaciers 

 often form a marked feature in the scenery, as for 

 instance, up Greenup Gill, and above Seathwaite, 

 Borrowdale ; on the east side of Honister Pass ; up 

 Longstrath Valley and at the head of Langdale ; 

 and in Ennerdale Valley, near where the footpath 

 crosses from Buttermere to Wastdale. At this last 

 spot they are particularly striking when looked 

 down upon from above, and by some people bave 

 been taken to be innumerable tumuli. Some long 

 mounds found in the lower parts of large valleys, 

 as at the ends of St. John's and Naddle Valleys, 

 and exactly'resembling moraines on the outside, are 

 formed of fine false bedded sand and gravel, and 

 these, as well as undoubted moraines, have some- 

 times formed lake-dams, though now cut through 

 and the lake drained. 



I trust it will now be evident that not only 

 different types of scenery are associated with different 

 classes of rock, and that atmospheric agencies have 

 the power of forming scenery as a whole, but also that 

 all the scenic detail and finer tracery are due to these 

 agencies working upon the minute peculiarities in 

 structure and composition of each kind of rock. But 

 it is evident, that if this be the way in which nature 

 has worked to produce our beautiful scenery, there 

 is yet something to make sure about. It cannot 

 be so, unless the apparent weakness of the agents 

 should be amply compensated for by the length of 

 time through which they may have acted. This 

 length of time we have at present only assumed, 

 and to show you' that the assumption is a true one, 

 it remains for me, in as few words as possible, to 

 give you an outline of the past history of the Lake 

 district. 



The oldest rocks in the district are the Skiddaw 

 slates ; these are very ancient finely stratified mud 

 rocks, containing in some places remains of marine 

 shells, worm-tracks, fucoids, shrimp-like crus- 

 taceans, and graptolites. These ancient mud 

 deposits, however, have been hardened, altered, 

 contorted, and cleaved. Their thickness is very 



great, and requires an enormous period of time for 

 their formation. The marine conditions which 

 probably prevailed for this long time over the 

 district were closed by a great series of volcanic 

 eruptions, at first submarine, the ashes ejected 

 being stratified beneath the sea and the lavas 

 fiowing over its bed. Very probably some areas of 

 dry land were then formed by the accumulation of 

 volcanic material, aided perhaps by elevation of the 

 sea bottom. The total absence of ordinary marine 

 sedimentary deposits and of any traces of fossils, in 

 the whole of the great thickness of ashes and lavas 

 now forming the mountains of Borrowdale, would 

 seem to indicate that much of the material must 

 have been ejected upon dry laud and part of il 

 perhaps deposited in large crater-lakes, for while 

 there are great thicknesses of unstratified or but 

 rudely stratified ashes and coarse breccias as- 

 sociated with the lava-flows, there are also many 

 intercalations of exceedingly fine-bedded ash, ap- 

 parently deposited beneath water of some kind. 



On the close of the volcanic activity, the district 

 was again sunk slowly beneath the sea, and the 

 various limestone, sandstone, and shale beds oi 

 Upper Silurian age were deposited unconformably 

 upon the great tiiickness of volcanic material. The 

 remains of these rocks may now be studied south 

 of Coniston and Windermere. At the close of the 

 Silurian period another gradual upheaval of the 

 ocean-bed took place, and as the laud slowly rose 

 above the sea, its waves planed away vast thick- 

 nesses of the strata, just as the sea is now doing 

 along our coast-line hard by, until when at length 

 the upheaving powers had got the mastery and a 

 tract of land stood fairly above the sea-level, the 

 lower rocks were in many places exposed at the 

 surface, by reason of the denudation which had 

 carried away the upper. 



Tuis tract of land being thus upheaved, the 

 rocks then curved, contorted, and cleaved, formed 

 the roughly-hewn block, so to speak, out of which 

 atmospheric agencies have ever siuce been carving 

 and sculptui-ing its present beautiful aspect. 

 Around it were deposited the old red conglomerate 

 beds : then the carboniferous limestone seas pro- 

 bably only washed its base, and afterwards coal- 

 measures and the Permian stiata were formed 

 around. And so on through the whole of the great 

 secondary epoch, during which the tria?, lias, oolite, 

 and chalk strata of the greater part of England 

 were being formed, was this district probably above 

 water and exposed to the denuding agencies of the 

 atmosphere. Also, through the whole of the 

 Tertiary epoch we have no evidence of submergence, 

 untd in the midst of the last glacial period the 

 country probably was sunk beneath the sea to a 

 depth of at least 1,500 feet. This immensely long 

 stretch of time, from the Old Ptcd to the Glacial 

 period, seems to my mind more than ample for the 



