146 Correspondence — Mr. Mackintosh, 



development in the same direction. This would lead to the conclu- 

 sion that there had, throughout a long lapse of geologic time, been 

 a general transportation of materials southward from old lands which 

 once occupied the region of the North Atlantic. 



BEACHLESS SEA-COASTS. 



Dear Sir, — Though the true form of the ground can be best 

 judged of by those who are in the habit of viewing it from greater 

 or less distances, such minute observations as those stated by Mr. 

 Green, in January last, are very important. It is, however, to 

 be regretted that so accomplished a surveyor should not be em- 

 powered, by a committee of the British Association, to examine 

 those sea-shores where level beaches are exceptional, and where the 

 slope, above and below mean water-mark, is characterized by every 

 form of escarpmental phenomena. On such shores, rising and falling 

 lines of cliff may not only be observed at certain heights above the 

 sea (where, in some instances, they might be called indirect sea- 

 cliffs, being the effect of coast-slips), but likewise passing under, 

 and from under, the water. Beachless shores are the general rule 

 on the west and north coasts of Ireland, among the Shetland and 

 Feroe Islands, etc. But, though on a smaller scale, they are very 

 characteristic of the coasts of Devon and Cornwall, where, in many 

 places, the base of a line of cliffs consists of a succession of heights 

 and hollows. The minor deviations from a plane presented by many 

 upland lines of cliff may thus be satisfactorily accounted for. To 

 deny that the general inclination of an escarpment can be the effect of 

 elevation is to ignore the established principle that the rise of the 

 land must be in excess of the rise of the bottom of the sea. In bring- 

 ing forward instances of escarpments, it is desirable that the meaning 

 attached to the word should be clearly stated. If an escarpment 

 runs along the strike it must maintain one level throughout, or a 

 succession of different levels. If an escarpment follows the dip of 

 the strata, it cannot run along the strike, and, unless the dip of the 

 table-land above corresponds, no downwardly-operating agent could 

 ever have commenced the work of escarpment-making. If an escarp- 

 ment crosses the dip of the strata it must have been denuded irre- 

 spectively of structure. Wherever the dip of the strata (local or 

 general) is as great as the dip of the escarpment, it is certain that 

 the former must have been unequally upheaved or depressed, or 

 thrown out of their originally horizontal position at some period, and 

 why not after the formation of the escarpment, unless in instances 

 where reasons to the contrary can be assigned ? These considera- 

 tions would seem to bo overlooked by subaerialists, who thus render 

 themselves liable to be misunderstood. 



The Kev. 0. Fisher's letter (p. 34, written before the appear- 

 ance of my letter in the December Number) contains observations 

 wonderfully agreeing with the views I have been advocating in your 



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