634 
Miniature Physical Geography. [November, 
valuable aids than pictures. Now I look upon a little 
streamlet as a working model, supplied by Nature herself, to 
illustrate the actions of great rivers. And I would ask my 
readers to look upon all the observations I am about to bring 
before their notice as small-scale exemplifications of the 
ways of Nature. Taken by themselves they are trivial to a 
degree. Taken in connection with the phenomena they 
exemplify, they may not perhaps be without interest. 
II. The Catchment Basin of Rivers. 
On almost any flat sandy shore one may watch the gradual 
establishment of miniature drainage areas and catchment 
basins. On one occasion, when I had been collecting fossils 
from the tertiary beds at Pegwell Bay, in Kent, I was caught, 
as I crossed the smooth flat left by the receding tide, in a 
heavy thunder-shower. To my eye the surface seemed 
perfectly even ; but as I stood and watched, the rain-drops 
collected into definite channels : these soon formed miniature 
rills, uniting into miniature streams, which ere long in their 
turn united into a miniature river. This kind of illustration 
is, however, so well known that I should not have drawn 
attention to it here had I not been able, in less than an hour 
and a half, to watch the separation of a mud-surface, to all 
appearances quite even, into a number of separate and dis- 
tinct drainage areas, each of which resembled a model of the 
catchment basin of some great river. 
III. The Cutting Sideways of Rivers . 
On almost any stretch of sand the aCtion of a miniature 
river on its banks may be watched. These little streams 
seldom or never flow in a straight course. I have sometimes 
on a sandy shore done my best to make a straight run for a 
little stream, and then, damming up its bed, deflected the 
miniature river into the artificial canal I had thus constructed. 
For a little while the stream would continue to keep a 
straightforward course ; but very soon some slight obstacle 
on one side would throw the main current towards the oppo- 
site bank. The result of this is soon apparent. This bank 
recedes, and, as it does so, it ceases to be a shelving slope , 
and becomes a tiny cliff. It continues to be rapidly under- 
mined by the aCtion of the stream, and the upper portions 
now and again topple over with a little splash into the water. 
In this way a bold curve is formed, which increases in length 
down stream. In the meanwhile, on the opposite shore of the 
