514 Prof. T. G. Bonney—On the Nagelflue of the Rigi, &c. 
mountain chain to the south-east had but rarely cut down to its 
crystalline foundations and that the visible portion of the Miocene 
Alps in this part of Switzerland consisted of Mesozoic and early 
Kainozoic rocks. 
3. The third point to which I would draw attention is the analogy 
of the nagelflue to some British rocks. Petrologically its likeness 
to the Bunter conglomerate of Central England is most remarkable. 
It resembles the latter in its confused assemblage of pebbles large 
and small, generally well rounded, though perhaps it contains blocks 
over 6" diameter more frequently, and is a little coarser. The 
matrix generally is harder, but this is due to the more quartzose 
character of that in the Bunter. The latter rock is commonly 
redder, though hardly more so than that which forms the fine crags 
above Vitznau. There are the same irregular partings of sand, often 
some feet in thickness, nay, here and there in the Rigi a sort of flag- 
stone banded with marl may be noted which recalls the waterstones 
of England. As we wander over the flanks of the Rigi we can 
hardly resist the conclusion that the two deposits are records of like 
physical causes. I may indeed add that except in colour the ordinary 
Swiss molasse has considerable resemblance to the softer sandstones 
in our Triassic series below the Keuper Marls. 
In Britain the beds which have a close petrological resemblance to 
the English Bunter are the Old Red Sandstones of England, Wales, 
and Scotland (excluding the volcanic rocks) and certain parts of the 
Lower Carboniferous series of Scotland, as, for example, the con- 
glomeratic sandstones of the Isle of Arran. All these closely 
resemble the gravels of recent formation in the great river valleys 
of the Alps; they differ from all marine pebble beds which I have 
examined in several particulars, difficult to describe, but readily 
recognized in the field. The nagelflue with much of the molasse, 
the Old Red Sandstone, the Calciferous Sandstone group of Scotland, 
are recognized without hesitation as of fluviatile or fluvio-lacustrine 
origin.’ We seem then justified in adding the Bunter series at least 
of Central and Northern England to the list of beds similarly 
formed, rather than in regarding it as the result of currents in a 
sea. In an inland sea it is improbable that adequate littoral currents 
would exist; in one communicating with the ocean we could hardly 
fail to obtain traces of marine organisms. It seems then to me that 
in the lower part of the English Trias we have a condition of things 
analogous to that of the Swiss nagelflue and molasse :—terrestrial 
fluviatile deposits not very distant from a sea, of which the Conti- 
nental Muschelkalk is one representive. For the product of a true 
inland sea in Britain we must look to the Keuper. 
1 In some very valuable remarks made after the reading of this paper, Mr. W. T. 
Blanford, F.R.S., referred to a series of conglomerates (which he considered of 
Pliocene age) largely developed in the Upper Siwalik in the north-west of India, on 
the flanks of the Himalayas, and west of the Indus in the Punjab and Sind (described 
as he informs me by Mr. Medlicott in the Manual of Geology of India, vol. i. pp. 
466, 525, 532, 641, and 570). These he compared with the gravel slopes along the 
base of the Himalayas (vol. 1. p. 403), expressing the opinion that all of them, with 
the nagelflue, were very probably the results of subaerial fluviatile action. 
