314 Reviews—Medlicott’s Southern flimalayan Ranges. 
the boundary is really a coast-line (which may perhaps have after- 
wards suffered from shifting), its irregular course being against the 
idea of an origin by a fault. The account of these beds is closed 
with a note of the fossils found in them, amongst which are many 
Plants, ‘probably of Middle Tertiary age.’ It is a strange thing, 
that whenever plants are found in Tertiary beds, they are nearly 
always said to be ‘Miocene’ or ‘ Middle Tertiary.’ 
The Nahun beds, our author says, consist in great part of a 
sharp soft: sandstone, here and there with clays and iron-ore, and at 
one place conglomerate. It is often hard to divide these from the. 
overlying beds. 
The Sivalik group, where most developed, may be subdivided into 
four; the lowest having more or less clay with the sandstone of 
which this group, as that below, mainly consists; the next is almost 
wholly sandstone, passing upwards into the third, which is conglo- 
meratic; whilst the fourth is made up of clays and conglomerates : 
at one spot the middle two are together 15,000 feet thick. As ‘no 
two sections . ... of these rocks are exactly alike,’ the geology of 
the Sivaliks can be no easy task to work out. We have before 
noticed that these beds are said by Mr. Medlicott to be in some 
measure related to the present system of valleys; and in proof of 
this he remarks, ‘the greater accumulation of boulder-deposits (in 
this group) in the immediate regions of the great rivers is very 
noticeable.’ At p. 122, we are told that at the great river-gorges 
there are transverse fractures; but our author does not accept the 
usual explanation of the waters having naturally selected these as 
weaker parts wherein to cut a channel, thinking that to do so may 
be ° jou eulins the cart before the horse,’ and suggesting, on the other 
hand, ‘whether the rivers, for the existence of which in this posi« 
tion during the Sivalik period we have such good evidence, 1 may not 
have been the predetermining cause of these ‘transverse fissures.’ 
In a short account of the Post-Sivalik beds, the author states his 
belief that the deep valleys and gorges have been formed ‘by river- 
action and atmospheric denudation generally,’ rather than by marine 
denudation, as has been supposed. 
In India, as elsewhere, rivers often go out of their way to cut a 
channel through hard rocks when a nearer course seems to have been 
open to them through softer beds, which ‘ may safely lead us to infer 
very remote conditions of the surface, very different from what is 
now apparent.’ With regard to the general structure of the hills, 
the author thinks that the disturbances in the Sub-Himalayan rocks. 
‘have no direct connection with the formation of the mountains;’ 
but that they have been caused by ‘ the thrust from the mountain- 
mass consequent on the sinking of that mass: the disturbance of 
the older rocks, however, he thinks to have been caused by eleva- 
tion. 
The last Ee is on Economic Geology, of which there is not 
much to be said, as it would be ‘difficult to find elsewhere an equal 
area of mountain-country so barren of mineral wealth.’ Building- 
stones and slate are to be got in places; gypsum, salt, iron, copper, 
