2821.] J .Geological Society, 71 



several years, but the existence of copper was not suspected 

 until some labourers who were employed to drain a swampy 

 piece of ground near the top of the hill of Cally, discovered 

 several masses of a rich ore. The mine has been since worked 

 under the direction of a company, and has already produced 63 

 to 70 tons of copper, worth nearly 15/. per ton. The direction 

 of the veins which run east and west of the shaft, that was sunk 

 to the depth of eight fathoms, on the spot where the ore was 

 first found, and seem to incline together, holds forth the prospect 

 of a regular vein in depth 



The ores are of a mixed character, containing the yellow and 

 coated varieties, with some green carbonate. 



A paper " On a recent deposit of Compact Limestone," by 

 Charles Stokes, Esq. MGS. was read. 



On examining a congeries of fragments of recent corals and 

 shells, supposed to be from the Mediterranean, portions of a 

 compact limestone were found enveloping and encrusting the 

 corals and shells ; and as it is well known that corals cannot 

 penetrate substances that are much softer than compact lime- 

 stone, it necessarily follows that this limestone must be a recent 

 deposit. One of the corals, discovered by a fortunate fracture, 

 retains all its beautiful structure, although completely imbedded 

 in limestone. 



An extract of a letter from Mr. Wilham Jack to H. T. Cole- 

 brooke, Esq. VPGS. dated Feb 5, 1820, and communicated by 

 Mr. Colebrooke, was read. 



The island of Penang off the Malay Peninsula is entirely com- 

 posed of granite, varying in the fineness and coarseness of its^ 

 grain, and sometimes in containing hornblende. In the island 

 of Singapore, the rocks are secondary, the principal one is a red 

 sandstone, of which the strata have a considerable dip to the 

 south, or south-eastward, and which changes in some parts to a 

 breccia or conglomerate. A small hill near the town is com- 

 posed of argillaceous ironstone. These are the prevaihng mine- 

 rals along the eastern coast of the Peninsula ; and the last 

 mentioned strata appear to be connected with the alluvial depo- 

 sits of tin, which are so abundant on this coast. The principal 

 mines are at Salengore and Pera, where the tin is found in hori- 

 zontal beds alternating with clay strata, and so pure as only 

 to require to be washed and reduced. Near this tin, the primi- 

 tive and volcanic ranges seem to meet; the former descending in 

 a south-eastern direction through the Malay Peninsula, and the 

 parallel island of Sumatra, from the Himalaya range, until it 

 comes in contact with the volcanic series, which runs from 

 thence nearly east, through Java and the chain of islands that 

 lie off its eastern extremity. 



