528 Correspondence — Mr. A. R. Hunt. 



Highlands, I believe it to have been produced after the post-Old 

 Bed deformation of the region ; probably long afterwards. In 

 some places it may hy accident agree with the Old lied floor ; but 

 as a whole it must differ from that floor, because the floor was 

 generally deformed after the Old Red strata were laid on it. Such 

 coincidence is against all probabilities. It is altogether unlikely 

 that a peneplain of so ancient a date as Middle Palaeozoic time 

 should have stood nearly level and close to sea-level until so 

 comparatively late a date as just before the uplift that allowed 

 the erosion of the glens. 



It may be noted that the peneplain of the Highlands is of more 

 imperfect form, of more difficult recognition, and hence attended 

 with more uncertainty in explanation, than various other uplifted 

 and dissected peneplains that I have seen : for example, that of 

 the Ardennes and Hunsriick, or that of southern New England, or 

 of western Pennsylvania and Virginia. The Scotch example must 

 have been a rugged one at the best. Local study may perhaps 

 identify certain peneplain areas that were well developed by the 

 denudation that formed them when the region stood lower, and 

 that are not yet altogether obliterated by the denudation that has 

 been initiated since the region has risen to about its present height. 

 The record of such a study I would gladly see. At the same time 

 it might be possible to infer by what sort of uplift the peneplain 

 gained its present order of altitude ; whether by an arching, such 

 as Hayes and Campbell have described for the uplifted peneplain 

 of the southern Appalachians (Nat. Geogr. Mag., Washington, vi, 

 1894, p. 63), or otherwise. It is perhaps to Scotch geographers 

 rather than to Scotch geologists that one must look for a solution 

 of this long-postponed problem ; but the solution will be welcome 

 whencesoever it comes. 



Harvard University, September, 1896. W. M. 1)AYIS. 



THE PARALLEL ROADS OF GLEN ROT. 

 Sik, — If the "parallel roads" are marine raised beaches, they 

 were accumulated between daily tide-marks, and as such are sure 

 to differ in character from beaches accumulated at more or less fixed 

 levels. Secondly, if the beaches wei-e marine and rocky, one or 

 other form of Littorinn could scarcely be absent, and Littorinas are 

 practically indestructible. In the loose sand of one at least of the 

 Devonshire raised beaches, these shells occur in perfect preservation ; 

 Liltorina obtusata is also said to occur in the deposits on Moel 

 Tryfaen. If, then, the beach-deposits of the parallel roads of 

 Glen Roy still survive, and no trace of Idttorina can be found in 

 them, the fact is hard to explain in such a sheltered valley, on the 

 hypothesis that the accumulations are of marine origin. If, in 

 addition to the absence of Littorina the beaches show no signs of 

 being accumulated between tide-marks, the difficulty of accepting 

 their marine origin will be greater still. The best evidence of 

 a raised-beach platform is its sloping towards the water as part 

 of an old tidal strand. Can such inclined planes be detected in the 

 case of the parallel roads of Glen Roy ? A. R. Hunt. 



