34 R. Chambers on Ancient Sea Margins. 



bly ventured to point out. He may be assured that there is m 

 my book no such extensive mistake as he is apprehensive of. 



The terraces and other markings there described are (overlooking 



a few peculiar cases where an explanation has been supplied) all 

 of them, as far as the fidelity of my observations may be de- 

 pended upon, strictly level. They are distinguished from ancient 

 river alluvia, not merely by this powerful feature, but still more 

 decidedly by local situation, their whole form and character, be- 

 ing manifestly not the remains of sheets of water which origin- 

 ally spread-across the whole of certain valleys at the lowest and 

 narrowest point, but the remains of benches of alluvium (if I may 

 so express myself) left in greater or less extent along the side of 

 wide valleys, altogether out of the range of any fluviatile opera- 

 tions (except in the special case of the deltas of side rivulets, 

 which I am here leaving out of view.) In Scotland, the sea 

 line of which is so irregular, a terrace is seen on a line of coast 

 towards the ocean — it turns round and passes also along the 

 country fronting towards a frith : — pass beyond the head of the 

 frith, and you still find the terrace, always level, and always at 

 the same level, where found at all. Let this kind of observation 

 be repeated many times, and what can be concluded but that the 

 part of the valley now far removed from salt water, was once the 

 bed of an estuary prolonged much beyond its present limits ? 

 We may ascend the valley till it becomes narrow enough to have 

 river terraces also ; but these are of a strikingly different char- 

 acter, much more palpable, of declining surface, always near to 

 the river both in horizontal and vertical space — in short, not to 

 be mistaken for the other class of objects by any but a very un- 

 prepared observer. Standing, therefore, on the facts which I 

 have amassed, I deny Mr. Dana's conclusion, that ' the terraces 

 in the higher portions of a country are not satisfactory evidences 

 of as many distinct elevations, nor of the actual height of any 

 elevations the country may have experienced' — and that ' the ter- 

 races towards the sea are more trustworthy.' There is positively 

 no distinction between them, beyond the simple fact that the sea 

 may still be visible from one position and not from the other. 



Mr. Dana's doubts lead him to call for observations of a more 

 searching and exact nature than he supposes to have yet been 

 made, and he lays down certain tests which he deems essential 

 in the investigation. Being conscious of having done only what 

 may reasonably be expected of one individual to open up the 

 enquiry, I desire nothing so much as to see others, both in this 

 country and elsewhere, engage in the same pursuit ; but I demur 

 to some of the tests, and a few of the particulars for examination 

 instituted by Mr. Dana, I deem unnecessary. I confine myself, 

 however, to a denial of Mr. Dana's proposition, that ' the marine 

 origin of a bed [understanding this term to include terraces] is 





