Correspondence — Mr. Marshall Hall. 333 



sure of the original relative position of the bones. He showed that the Plas Heaton 

 Cave was on a hill rising from the top of the plateau, while the Cefn, Brysgill, and 

 Galltfsenan Caves were in the gorge cut through that plateau, and therefore that the 

 Plas Heaton Cave was probably formed, and might possibly have been first occupied 

 at a much earlier period than the others. As it appeared to pass under that part of 

 the hill which is overlapped by heavy drift, he thought it quite possible that this may 

 have been a pre-Glacial cave, and that by-and-bye we may find evidence of a pre- 

 Glacial fauna in it. 



The Rev. W. S. Symonds mentioned that in some of the pot-holes in the roof of 

 the Cefn cave he bad procured silt containing remains of shells determined by Mr. 

 Jeffreys to be marine. 



Mr. Hughes explained that these shells had probably been washed in from the 

 superficial marine drift of the district. 



Mr. Dawkins, in reply, expressed his belief that though the excavations of the caves 

 in question might have taken place at different periods, yet that their occupation was, 

 geologically speaking, contemporaneous. 



coI^I^Es:po2^^x):E2^rc:B. 



TERRACES OF NORWAY. 



Sir, — As the translator of Professor Kjerulf's pamphlet, and a 

 visitor to many of the terraces he describes, may I be allowed, in 

 answer to Colonel Greenwood, to occupy half a dozen lines ? 



The terraces occupy the whole breadth of valleys, often very wide. 

 The upper surface is almost level, save where a groove is cut by an 

 existing stream. They end, as Kjerulf says, in an abrupt slope, 

 often succeeded by another terrace. 



I especially recommend travellers to go to Aardal, and ascend by 

 loch and river to see the grandest imaginable fall — the Moik Pors. 

 In their journey they will see the terrace formation on a very re- 

 markable scale, and I hardly think they will agree with Colonel 

 Greenwood. In fact, few geological problems have so patent a 

 solution. 



I shall at any time be happy to sketch out a route, embracing 

 some of the more remarkable terraces, for any traveller proposing to 

 visit them. 



, Marshall Hall. 



New University Club, May 9, 1871. 



CONCRETIONARY STRUCTFRE IN PLASTER. 



Sir, — The referen-ce in Notes and Queries of your April number 

 (page 192), to concretionary structure in the plaster of old walls 

 reminds me that years ago, when G. H. K, and myself were colleagues, 

 I used frequently to note it, and he may perhaps remember seeing 

 my rubbings and copies therefrom. 



Some of the best of these were obtained in partly ruined buildings, 

 affording a little occupation during showers, etc. 



Unfortunately the whereabouts of drawings or notes is now 

 unknown, but I can recollect that these markings were not at all 

 uncommon, and were sometimes very perfect. 



