424 Proceedings of the Royal Society. 



"bed consists of layers of clay and very fine sand, two feet thick. 

 The second bed is of plastic clay-marl, containing many small wa- 

 ter-worn pebbles, chiefly of clay-slate, two feet thick. The third 

 is a stratum so filled with broken and comminuted bones, as apparent* 

 ly to consist entirely of that material, two feet thick. It is in this 

 bed that all the bones mentioned, except those of the bears, are 

 found. Immediately below is the fourth bed, consisting of plastic 

 marl-clay, with many water-worn pebbles of slate and compact fel- 

 spar, with angular pieces of limestone ; this is also two feet thick. 

 The fifth bed consists of fine sand, which seldom contains any peb- 

 bles. It rests on the floor of the cavern, and has usually a depth 

 of four feet. In one part of the cave, however, Dr Gumming de- 

 tected below this bed a floor of hard stalagmite, about sixteen feet 

 square ; and on breaking it up, bones of bears were found mingled 

 with sand and large water-worn pebbles of the rocks already men- 

 tioned. 



One of the most interesting observations which occurred to the 

 author during his investigation was, that the stratified earthy mate- 

 rials filling tlie cave were not deposited horizontally, but had an 

 evident dip, which he remarked was in the same direction and ap- 

 parent inclination as that of the limestone rock itself. The impor- 

 tant inference he drew from this is, that the stratified materials 

 "were deposited in the cave before the limestone received its present 

 position ; and he conjectured, that the animals whose remains are 

 here preserved may iiave existed even before the last great distur- 

 bances of our carboniferous system of rocks. Should similar phe- 

 nomena be observed in other caves, it would perhaps carry back 

 the existence of mammiferous animals to geological epochs more 

 ancient than generally supposed ; and account for the occurrence 

 of diluvial materials in similar situations, without the startling sup- 

 position of extensive degradations of solid rocks, by causes appa- 

 rently inadequate to produce them. 



Another cave exists in tiie same neighbourhood, in which bones 

 have also been found. It is near the village of Pont Newydd. In 

 its bottom was found a collection of hyaena bones, in a mass of 

 calc-sinter and gravel, four feet in thickness. 



The author illustrated his paper by a view of the Clifl's of Cefn, 

 and by a plan and sections of the principal cave. 



2. Experiments on the Growth of the Fry of the Salmon, 

 from the exclusion of the Ova to the age of seven 

 months. By Mr John Shaw. 



This interesting memoir is published in the present volume of 

 this Journal. 



January 1. 1838.— Dr Abercrombie, V. P. in the Chair. 

 The following communication was read: — 



On the Terrestrial Mechanism of the Tides. By John 

 Scott Russell, Esq. 



Under the title Terrestrial Mechanism of the Tides, the author 



