134] A TOPOGRAPHICAL 



mean title of the ocean. The lime-stone hills may be estimated ai 

 200 to 300 feet above this level, and Corney-hill Rowley at 400 

 feet : a considerable part of the lime-stone is upon the level of the 

 canal, and some beneath it, that to the N. E. of Walsall being 

 nearly on the same level, but none there so much elevated as the 

 Dudley and Sedgeley hills. The coal-pit shafts are generally 

 sunk at near the canal level, but none have, we believe, yet pene- 

 trated so deep as to the level of the sea. 



The lime-stone beds consist of thin layers of the thickness from 

 three to eight inches. In the centre of the hills are large indefi- 

 nite masses, called crog, of good lime-stone. The beds are sepa- 

 rated from each other by substances called ratch and bavin, which 

 are mixtures of calcareous and argillaceous earth. Immediately 

 under the surface of the ground, detached masses of good lime- 

 stone are found in loose earth, which masses are called turf-stone. 

 Some of these beds contain abundance of petrified shells, amongst 

 which is a representation of an animal called by the workmen a 

 locust, by others the Dudley fossil. * 



Strata above the Coal. These are very various in different places, 

 without uniformity; and the depth of the pits are very different. 

 In some places the coal has been got at the surface of the ground 

 in open quarries, in others the pits are 140 yards deep, though the 

 beds of coal are similar in a considerable degree in thickness, qua- 

 lity, and relative position. The strata containing iron ore (called 

 iron-stone,) and those of the finer kind of clay, called fire-clay, 

 pipe-clay, and pot-clay, from its power of resisting heat and its 

 fitness for making tobacco-pipes and glass-house pots, are the next 

 in order with regard to uniformity. As to the other intervening 

 masses of rock, bind, clunch, and especially the upper earths, they 

 vary frequently in the same field, or even at a few yards distance. 

 The following is a list of measures found in digging a coal-pit in 

 Tividale colliery : 



Feet In. 



9. White clunch, 3 3 



10. Grey clunch, 7 3 



11. Red wild stuff, 41 6 



12. Greenish rock, 4 



13. Red Avild stuff, 7 6 



14. Binds, with balls of grey 



rock, 11 



Carried forward, .... 107 1 



Feet In 



1. Soil, 1 



2. Brick clay, 5 6 



3. Brown-coloured roach, (1) 6 



4. Blue clay, 1 



5. Red-coloured roach, 5 



6. Rock, with coal interspers- 



ed, (2) 5 



7. Clunch and iron-stone, (3) 8 3 



8. Smutt, (4) 10 



