20 
the Himalaya mountains, to the height of 16,000 feet, showing its 
former extent and subsequent elevation.” 
Over these Middle Hocene deposits, again we find, in our own 
and the Paris areas, a return to land and freshwater conditions 
in the Upper Eocene beds of the Isle of Wight, from the Headon 
to Hempstead series, inclusive, and which are estimated to be about 
600 feet thick. Their equivalents include the gypsum beds, so rich 
in peculiar mammalia of this period, near Paris. 
Nor were these the only intervening strata between the Croydon 
gravel and the London Clay, for the whole Miocene period, rich in 
a varied Fauna and Flora, occupied with its marine beds large areas 
in Europe and the United States. Its land and freshwater beds 
are seen in Greenland and Iceland. The luxuriant forests of 
this period, differing from the previous vegetation of the 
London clay, and more nearly approaching our own times, have 
given the thick deposits of brown coal so largely worked over the 
continent of Europe. During this period great volcanic out- 
bursts took place in Greenland and in Britain, as seen in the Giant’s 
Causeway, Staffa, &c.+ Again, after this period, occurred the eleva- 
tion of, or an increase in the height of, the Pyrenees, Alps, 
Carpathians, and Himalayas, for, upon their upraised flanks we 
find, at considerable heights, from 10,000 to 16,000 feet, traces of 
the Miocene and Eocene strata, the latter in the Alps, sometimes so 
altered, that they can be used as slates for roofing. 
* When we have once arrived at the conviction that the nummulitic formation 
occupies a middle and upper place in the Eocene series, we are struck with the com- 
paratively modern date to which some of the greatest revolutions in the physical 
geography of Europe, Asia, and Northern Africa must be referred. All the mountain 
chains, such as the Alps, Pyrenees, Carpathians, and Himalayas, into the composition of 
whose central and loftiest parts the nummulitic strata enter bodily, could have had no 
existence till after the Eocene period. During that period the sea prevailed where these 
chains now rise, for nummulites and their accompanying testacea, were unquestionably 
inhabitants of salt water. Before these events, comprising the conversion of a wide area 
from a sea to a continent, England had baen peopled by various quadrupeds, by herbivo- 
rous pachyderms, by insectivorous bats, and by opossums. Almost all the volcanoes, 
which preserve any remains of their original form, or from the craters of which lava 
streams can be traced, are more modern than the Eocene fauna now under consideration ; 
and besides these superficial movements of the action of heat, Plutonic influences have 
worked vast changes in the texture of rocks within" the same period. Some members of 
the nummulitic and overlying tertiary strata, called flysch, have actually been converted 
in the Central Alps into crystalline rocks, and transformed into marble, quartz-rock, 
mica-schist, and gneiss.—Lyell, Elements of Geology, 1874, p. 261. 
+ The present Europe, partly then a continent, was, in miocene times, the theatre 
of widespread volcanic eruptions in ceutral France, Germany, and that part of the 
British Islands now known as the Inner Hebrides. In that region they play a much 
more important part in connection with the physical geography of our country than they 
do at Bovey Tracey. In the adjacent land of Antrim, through the Isles of Mull, Rum, 
Rigg, Cana, Muck, and Skye, a vast broken belt of miocene volcanic rocks forms great 
part of the Inner Hebrides ; and far beyond Britain, in the Faroe Islands, and in Iceland, 
the same volcanic series is found now, fragments, perhaps, of one large continuous ter- 
ritory ; or, if not, at all events of a series of large islands of which the Faroes make one 
of the fragments.—Prof. Ramsay, Physical Geology and Geography of Great Britain, 
1874, p. 129. 
z ar J. W. Judd, in his valuable and elaborate paper ‘‘On the Secondary Rocks of 
Scotland,” when speaking of the basalts of the Antrim and the Inner Hebrides, says, 
‘Thus we are led to the conclusion that along a line stretching at least 400 miles from 
north to south, in the north-western part of the British archipelago, there rose, during a 
great portion of the Tertiary period, a chain of volcanoes ina state of violent but inter- 
mittent eruption.’—Quart. Journ. Geol. Soc., vol. xxx., p. 275. 
