Edinburgh Geological Socicty. 569 
be any fact or any conception which is even more significant or more, 
impressive, it is the farther fact that, as regards the method of that 
new birth—so recent, so fresh—with the times before and the times 
after—so clear and close at hand, we have not as yet, so far as the 
physical sciences are concerned, one single ray of light. And yet the 
intelligibility of nature does not fail us. But the kind of intelligi- 
bility which we find lies in an appeal to higher faculties than those: 
which deal with physical conceptions. We can see a reason; but we 
cannot see a cause. The reason which we can see is simply this—that 
up to a certain epoch the house and the home of man was not suffi- 
ciently ready for him. Those creatures which are his best servants, 
and some ot which are the indispensable elements of his culture and 
civilization, had not been introduced. This is a fact, again, which 
belongs to our science. And if there be any other facts touching the 
earliest relics of man which can be found in geological deposits, surely 
these are facts on which we are bound to observe most carefully and to 
reason most closely. Let me go to the point at once. It is almost 
universally assumed that the beds of gravel, of brick-earth, in which 
or under which human implements of the paleolithic type have been 
found, are all river gravels, and fluviatile silts. I question this 
assumption altogether. In order to make it square with facts, it is 
continually necessary to assume that rivers existed where none exist 
now, and that other rivers which do exist have once run along the tops 
of the hills which now enclose them; and further, that in no other 
way can water have overflowed the whole existing drainage. These 
assumptions are always more or less arbitrary, and in some cases are 
demonstrably unsound. The marine gravel with dead shells of exist-— 
ing species found high up on the Welsh mountains, and also found near 
the top of the Midland Watershed of England, render it all but certain 
that the whole of England has been under the sea, in times so recent 
that zoologically they belong to the epoch in which we now live. All 
the older gravels which pre-existed upon the surface so inundated 
must have been then widely broken up and redistributed; and new 
gravel beds must have been formed by the washing away of the finer 
materials from out of stony soils. Accordingly, we find that the 
gravels which are called river gravels are very often full of foreign 
material—foreign, I mean, to the drainage basin of the rivers with 
which they are connected. And here let it be observed that whilst the 
absence of such foreign materials would not disprove marine redistri- 
bution, the presence of them in any one case may be conclusive proof 
of a much wider marine submergence than any affecting only the spot 
on which they are found. The distance to which the sea might scatter 
pre-existing gravels would depend entirely on the violence of currents 
or the gentleness of submersion. But if we find anywhere in gravels, 
high above the lines of existing drainage, quantities of material which 
must have been brought from a great distance, we may be sure that the 
currents which brought them there havesimply run with lessrapidity over 
the areas where no such materials are found. I can testify by my own 
observation that what are called the high level gravels connected with 
the valley of the Thames are full of lumps and pebbles of rock which 
do not belong to the drainage of the Thames valley, but must have 
