98 



PK0E. T. M'XEPTNY HUGHES ON THE 



of the world's history when there were land and rain and streams ; but 

 these superficial deposits would be the first to be destroyed, especially 

 in subsequent submergences, and the chances are that only the latest 

 deposits of that kind are seen exposed in any district. 



At any rate the alluvium and rainwash of the Yale of Clwyd 

 belongs to the age that succeeded the emergence, and is still going on. 



Patches of alluvium can be traced far up into the hill. For 

 example, down the road between Wern and Penybanc, N. of Pouty- 

 rddol, there is a grey gravel, and here and there beds of sand. It 

 was, so far as I could see, all composed of Silurian and Cambrian 

 rocks. 



We have no data for determining the absolute age of the alluvial 

 deposits in the upper part of the Vale. I have a very fine, partly 

 ground neolithic implement, picked up by Mr. Stuart Menteith in the 

 gravel of the Elwy above St. Asaph, and given to me ; but there is no 

 evidence as to whether this was carried on to the gravelly bed of 

 the river from the alluvial gravel which there spread across the 

 valley from side to side, or was dropped in from the surface-soil. 

 The North Wales fenlands of Morfa Rhuddlan were formed where 

 the river spread over the low flat lands ; its velocity was checked, 

 and the transport of gravel ceased. So below St. Asaph, near 

 Rhuddlan and Rhyl, for instance, the gravel banks give way to 

 tidal silt, to which we will refer as the Morfa Rhuddlan beds, and 

 which is probably newer still than some, at any rate, of the gravel 

 near St. Asaph. The course of the river has altered considerably 

 since the water-towers of Rhuddlan Castle were built. 



Sections through the silt have been sunk for various purposes here 

 and there. Por instance, I was informed that when the railway 

 was being made along the coast, they dug out the blue estuarine 

 clay to a depth of 18 feet to make the embankment, and near the 

 bottom of the excavation found the skull of Bos longifrons, and the 

 antlers of Cervus elaphus, which are now preserved in the Cambrian 

 inn at Pensarn. These remains occur here and there all through the 

 deposit. The Balani on the points of another pair of antlers show 

 that it had projected above the surface of the clay for some 

 time. 



On the south of Rhyl a trench cut out for draining-purposes 

 exposed the following section : — 



ft. in. 



a. Surface-soil with broken shells of Buccinum imdatum 



at the base, perhaps artificially carried there. 



b. Blue clay, weathering brown in the upper part, con- 



taining shells of Scrobicularia piperata, with valves 

 adherent 1 0 



c. Peaty silt, no timber 0 6 



d. Peat with trees 15 ft. in length and 1 ft. 6 in. in 



diameter . 2 0 



e. Blue clay 3 0 



On the Morfa Rhuddlan beds rest the sand-dunes and the shingle 

 which form a great natural bulwark against the sea, which is driven 

 fiercely on this coast by the north-west winds. These Eolian beds 



