48 Mr. Forster's Notice of a Basaltic Dyke. 



acid, and tested with prussiate of potass, and oxalate of ammonia, 

 indicated the presence of Iron and Lime, the Jbrmer in considerable 

 abundance. 



No. 2. Is a specimen of Basalt from the body of the Dyke where it 

 was intersected by the discovery drift A B (see Plate IX.)— specific 

 gravity 2"674i — colour greyish-black — ^fracture imperfectly conchoidal. 



No. 3. Specimen from the Main Coal Seam, near the bottom of the 

 William pit — specific gravity 1*275. This Coal is of the very finest 

 quality as a bituminous or coking Coal, very free from Sulphur, and 

 well adapted for manufacturing purposes. It contains in 100 parts, 



Carbon or Coke, 71 



Volatile matter, 28 



Incombustible earthy residuum, I'l 



100-1 



No. 4. Specimen from the 8-inch bed of Coal overlying the Basalt and 

 Coke in the William pit. Specific gravity 1'254. Very inferior in lustre 

 to the Main Coal, and containing a considerable proportion of Iron Py- 

 rites. Bituminous, giving a large quantity of very fine gas, by distillation. 

 It contains, in 100 parts. 



Carbon or Coke, 64*7 



Volatile matter, 34* 



Incombustible earthy matter, V3 



100-0 



It is very remarkable that this Coal should immediately repose upon, 

 and be found in actual contact with, the 10-feet beds of Basalt and Coke, 

 and yet retain all the above properties. 



No. 5. Specimen from the 10-feet stratum of carbonized Coal in the 

 William pit. Specific gravity 1 '660. When calcined in a strong red 

 heat there remained 35^ per cent, of a dirty-white, heavy powder, prin- 

 cipally silicious, but containing a minute proportion of Iron. On its 



