April 1 6, 1874] 



NATURE 



473 



died out, and was replaced by plane-trees, poplars, elms, willows, 

 and maples ; while cinnamons, figs, vines, laurels, and Proloacece 

 still continued to flourish. In the woods, on the meadows, and 

 in the waters respectively, the Mmtodon angnsluhns, the rhino- 

 ceros, Chceropotamus, Dicholiune, deer, Dinotheriiim, hippopo- 

 tamus, crocodiles, salamanders, fish, and numerous other creatures 

 roamed at pleasure, while the air and the land were tenanted by 

 dragon-flies, ants, beetles, and other insects, of which more than 

 Soo species have been distinguished. 



I now come to the chief part of this lecture, which is to 

 account for the origin of the Rhine : for at that earlier time the 

 Rhine had no existence in this valley, and indeed there is proof 

 that instead of the main drainage of the area, flowing from south 

 to north as it does now through this valley, the waters drained 

 from north to south ; and the pebbles of the SchwartzwaM, 

 instead of being carried north as they are now, were carried 

 southward by minor rivers, and found their way into Switzer- 

 land, thus helping to form some of the conglomerate rocks of which 

 the Miocene strata of Switzerland to a great extent consist. 



Not only had the Rhine no existence then, but the romantic 

 gorge of the river, with which' so many are familiar, had 

 no existence either. It has been customary sometimes to attri- 

 bute the formation of that gorge to violent disturbance and 

 fracture of the strata, by which the waters were allowed to escape 

 from south to north. I have no belief in such violent distur- 

 bances having any place in the modern economy of the world, 

 nor yet in such cataclysmal action having ever affected the ancient 

 world, as far as it is in the power of geologists to trace back events 

 from the present day to the oldest known geological periods. 



After the Miocene epoch had lasted for a long period of time, 

 there occurred another disturbance of the European region, and 

 of much of the rest of the world besides, though it is only the 

 Alpine region and the countries north of the Alps that we have 

 now to deal with. This second disturbance of the Alps produced 

 a great upheaval of the Miocene strata. All the IWiocene lakes 

 that occupied the old lowlands of Switzerland and extended far east 

 into what is now the Austrian dominions and into Asia itself, — all 

 that area, as far as the Alps are concerned, was gradually heaved 

 up high above the level of the fea, and those beds of conglome- 

 rates, sandstones, and marls that form the lowlands of Switzer- 

 land, and all across what is now the Jura, were disturbed to such 

 an extent that the strata now forming the Right and Rosberg and 

 other sub-Alpine hills were partly raised to a height of at least 

 5, Soo ft. above the level of the sea, and probably much more. 

 The lower parts of Central Switzerland, about the Lake of 

 Geneva, the Lake of Constance, and Neufchatel, still stand at 

 heights of from 1,200 ft. to 1,300 ft. above that level. Then the 

 range of the Jura first rose up to form a mountain-ch.ain, and 

 this is the proof of these disturbances. First we know that the 

 Miocene rocks originally lay all the way from the Alps to the 

 Taunusin flat-lying strata. During that period a vast quantity of 

 Miocene pebbles were carried into the lakes, which were by and 

 by consolidated into an exceedingly coarse conglomerate. Anyone 

 who has ascended the Righi will remember that nearly the whole 

 of it is formed of this coarse conglomerate, proving the prodigious 

 amount of waste that the Alps underwent during the Miocene 

 period. When we consider the amount of this waste, even though 

 the waters of the Miocene period lay but little above the level of 

 the sea, still in my opinion it is probable that the Alps themselves 

 were then quite as high, if not higher, than they are now. For 

 the prodigious amount of waste proved by the conglomerate, 

 indicates the removal of an enormous amomit of material from 

 the pre- Miocene Alps. 



After the disturbance which raised the Jura and the Miocene 

 strata of the lowlands of Switzerland, this is what took place. 

 Alongwith the contorted secondary strata of the Jura, the Miocene 

 beds that previously covered them were thrown into a number of 

 anticlinal and synclinal curves, and the greater part of the Miocene 

 material over that area having since been removed by denudation, 

 only a few outlying fr.igments of these strata remain, left in those 

 wonderful upland basin-.shaped hollows of the Jura, which still 

 attest the original continuity of the Middle Tertiary deposits all 

 the way from the base of the pre-Miocene Alps to the northern 

 liase of the Taunus. 



When the post-Miocene disturbance of the whole of this area 

 took place the general effect was, that much of the Swiss Miocene 

 area was contorted and raised high into the air, while between 

 the Jura and the Taunus, the equivalent strata were simply heaved 

 up and tilted so as to form a long inclined plain sloping northerly 

 and lying between the Vosges and the Schwartzwald, and the 



surface of which may have been about 1,200 or 1,300 ft. above 

 the present level of the sea where Basel now stands, and about 

 1,000 to 1, 100 ft. high where the opening of the gorge now 

 begins near Bingen. 



Before this wide-spreading disturbance took place, the Rhine 

 had no existence, for up to that time such small rivers as occa- 

 sionally ran in the more ancient Miocene valley flowed partly 

 south. But when the inclined plain was fairly completed, the 

 result in the long run was th.at for the first time the great general 

 drainage of the area began to run from south to north, and the 

 Rhine was established flowing at a height which we may roughly 

 speak of as having been 500 ft. higher than now, because at that 

 time all the great valley between Basle and Bingen was filled to 

 that height with Miocene strata. We know this to be a fact by 

 an examination of the valley on the right hand and the left, from 

 Bingen towards Basle, for every here and there, we find table- 

 shaped hills formed of flat-lying Miocene strata, which border 

 the present alluvial plain of the Rhine and abut upon the more 

 ancient mountains on either side. The history revealed by this 

 fact is plain to anyone accustomed to reason on geological pheno- 

 mena. The strata forming scarped slopes on opposite sides of 

 the valley were once united, and their early continuity has been 

 destroyed, simply by long-continued watery wa.ste and denuda- 

 tion. They are indeed only the relics of an older phase of the 

 physical geography of the district, when the surface of the plain 

 stood about 500 it. higher th.in it does at present. 



Now when the Rhine first began to flow, the river then passed 

 through a high upland \alley with gently sloping sides that lay 

 between the Taunus and the Hundsruck, and which in no manner 

 resembled the precipitous clifls that now bound the Rhine in the 

 gorge below Bingen. The bottom of part of this old upland valley 

 still forms a narrow terraced plain, immediately above and beyond 

 the edge of the cliffy gorge of the Rhine. It is not always con- 

 tinuous on both sides of the gorge, but enough of it remains 

 to attest its original contir.uity at heights of from 400 to 500 ft. 

 above the present level of the river. Now what I wish to 

 persuade you of is this, that the Rhine flowing in this valley 

 by degrees began to cut out its own gorge, and that it was not 

 produced by fracture. Every running river is busy eroding its 

 channel, especially where the ground is at all steep. That is 

 one of the main functions of running waters. They are con- 

 stantly deepening their channels and carrying the sediments so 

 formed from higher to lower levels, till in the course of time 

 they find their way into lakes or the sea. 



When we first enter the gcrge of the Rhine, going southward, 

 one feature that strikes the geological observer is the constant 

 recurrence of this old terrace backed by the hilly country beyond. 

 On the left bank, overlooking Bingen, the flat-topped spur of the 

 Rochus-berg, about the same height as the tops of the neighbouring 

 Miocene tabular hills, first strikes the eye. When lairly within 

 the gorge below Niederheimbach, beyond its upper edge the old 

 river plain is seen gently sloping to the north, while the sides of 

 the gorge itself is seamed by numerous gullies worn by occasional 

 torrents since the great ravine — a kind of canon — has been cut 

 down to its present level. 



At Welmich, below Niederheimbach, looking down the river, 

 the edge of the terraced plain is seen receding northward in 

 long perspective, and at Salzig, still further down, the features 

 so well shown near Niederheimbach are again reproduced. The 

 same outline occurs again and again all down the river between 

 Bingen andCoblenz, and equally below Andetnach, as for instance 

 at Rheineck. Finally, above the Siebengebirge, just about the 

 mouth of the gorge, looking up the river, the long eastern hills slop- 

 ing to the river end in a terrace corresponding in general height and 

 outline to those already mentioned. The general conclusion to 

 be drawn from these observations is that at heights of from 

 450 to 5C0 ft. above the present river this ancient river terrace 

 has a persistent gentle slope from south to north which approxi- 

 mately corresponds to that of the existing river. 



The inference is plain : that formerly throughout the length 

 of what is now the gorge the river flowed at that high terraced 

 level, at a time when the plain above the gorge was so deeply 

 filled with Miocene strata that the level of the river, where 

 Mainz and Bingen now stand, was as high as the upland terrace 

 that crowns the gorge between Bingen and Rolandseck. By 

 degrees the river began to excavate the gorge, and slowly cutting 

 deeper and deeper, and at the same time winding and ever 

 changing its channel through the great plain between the Jura 

 and the Taunus, by slow gradation it wasted away the surface 

 of that plain more and more, and the matter won from that 



