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of man. Hence my stand in a hypothetical gi-avel pit of this character, 

 "which we may suppose to be situated upon the north side of the Stour, near 

 Canterbury. 



The second question now presents itself — whence were these 

 materials derived? 



Clearly from the chalk, ab initio, but in our gravel pit not directly, 

 for the former lies many feet below, and between the two intervene Eocene 

 beds of sand and pebbles ; the latter covered with London clay. The chalk 

 flints composing our quarry, must then have been transported from some 

 other part where chalk reaches the surface. The gravel contains too, 

 some rounded black pebbles, small in size and slightly flattened in shape, 

 very dissimilar to the large rounded boulders of different tints, shaped by 

 the rolling action of the sea upon our present beach. "Where did they 

 come from ? If we are acquainted with the Thanct, Woolwich, and 

 Oldhaven series of the Tertiary beds resting iipon the chalk, but be- 

 neath the London clay, we shall recognise these black pebbles as 

 belonging to some one of them ; but as we may likewise find in the 

 gravel pieces of sandstone and ironstone identical with those in the 

 tertiary beds, it makes the derivation of these materials doubly sure. 



Thirdly : — How were these heterogeneous materials brought to their 

 present position ? We know that the sea is one agent that carries up 

 material into beaches. But these beds are evidently very difl'erent from 

 sea beaches, and there is no evidence of any modern sea having been 

 near ! Rivers we know also heap up the materials carried by 

 their running waters, and if the flow be of sufficiimt depth and velocity, 

 it will also remove and redeposit gravel. Elvers of a torrential 

 character abrade the older beds over which the waters flow, to carry and 

 mix up the materials so similarly to these that we may safely assume this 

 to have been the mode of action. 



But supposing these beds were thus formed, how could the present 

 streams (at a far lower lever and with little velocity), have shaped these 

 ten'aces ? The answer suggested is that at some former period the rivers 

 occupied a much higher position, and that in progress of time they have 

 cut their beds down to the present level. 



Our examination of the gravel pit has then led to several important 

 questions, and the answers may appear conclusive, but they demand that 

 a long period of time should have been occupied by these actions, and 

 under several climatal conditions that no longer exist. For corroboration 

 our typical pit may be compared with existing ones in similar terraces, 

 along the high banks of the rivers Thames, Medway, and Stour, and 

 their contiguous streams, which all present the same characters, and show 

 no signs of unequal elevation or depression. We now invoke the spirits 

 of the geologists to tell us something more. 



First, an examination of the gravels themselves, or the brick earths 

 with which they are associated, (or which often replace them in position) 

 has yielded to the attentive examiner a number of fossils ; amongst these 



