Some Expermenls on the Comlustlon of the Diamond. 429 



coralline (species unknown to me) is often met with. Near Dun- 

 raven large fossil nautili, and at Llanbletliian delicate casts of 

 cornua amnionis in calcareous spar. Shells of several other genera 

 occur less frequentlv. The breccia above mentioned occurs, I 

 believe, close to the blue lias at the mouth of Cadorton river. 



Small ovsters, nearly in a recent state, occur in the seams of 

 clay between the layers. 



Sutton Stone. 



The Sutton or Silton stone which occurs near the Dunraven 

 caves is of a greyish-white colour, and contains cockles, muscles 

 and scollops converted into silex. The rock makes but indifferent 

 lime, as it contains much siliceous matter. It bears the weather 

 well, as the copings of Swansea Castle, Neath Abbey, &c. evince. 

 The Sutton stone overlies the masses of rock which rise round 

 and in front of the caves. These masses are calcareous, but 

 mixed with much argil of a reddish brown or black colour ; and 

 it is curious, that this species of rock occurs no where else in 

 Glamorganshire. 



Coal Basin, 

 This important formation with its valuable beds of different 

 coals, and argillaceous iron ore, has been well described by Mr. 

 Martin. (Pliil. Trans. 1806.) It comprises all the tract lying 

 N. of a line drawn eastward from Taybach, along the hills be- 

 hind Bridgend and Lantrissent to the extremity of the county. 

 The iron ore is most abundant round Merthyr and at the upper 

 part of Heath Valley. The picturesque scenes in the vales of 

 Tawey, Neath, Dgmore, Rondda and Taaf, lie within its range. 

 The mountain lime rises to the north of the basin at Castell 

 Morlais near Merthyr. A valuable bed of siliceous freestone is 

 met with at Coity ; it lies between-^he coal basin and mountain 

 lime ; it is also worked near Pyle. At Sutton If mile W. of 

 Dunraven a valuable bed of calcareous freestone much used for 

 ornamental masonry rests upon tlie lias near its junction with 

 the mountain lime. 

 Dec. 3, 1814. 



LXVII. Some Experiments on the Combustion of the Diamond 

 . and other carbotiaceous Substances. By Sir Humphry 

 D.wY, LL.D. F.R.S. V.P.R.L* 



OiNCE it has been shown by various accurate experiments, that 

 the diamoud and conmion carbonaceous substances consume 

 nearly the same quantity of oxygen in combustion, and produce 



• lioiu tlic Philosophical Triwisaclions for 1811, pari ii. 



a gas 



