of Hampshire and Dorsetshire, 2.55 



coal varies from 1,4 to 1,558.* There are frequently ///?j- of day 

 passing through this earthy brown-coal. 



I have seen at West Lulworth, another brown-coal passing into 

 pitch coal, in a black loose quartzose sandstone, in which it makes a 

 very thin layer or seam. It hardly burns with a flame, but chars 

 like wood, emitting an empyreumatic or subacid smell. The spec. 

 grav. of the specimen 1 tried, was 1,340. This last species of com- 

 bustible matter, as well as the former, is used by the poor people as 

 fuel, and they may be both referred, I think, to the spurious coal of 

 Mr. Kirwan ; the range of the specific gravity which he gives, is 

 that of 1,500 to l,600t 



III. Marl. 



This rock occupies a pretty large extent along the coast : I have 

 observed the four following varieties. 



(a) Marl of an earthy semi-indurated texture, which assumes 

 spontaneously polyhedral forms, and contains nodules or kidneys of 

 sulphuret of iron, some of which have undergone a partial decom- 

 position. It has no lustre, the fracture is coarse, the colour of a 

 bluish-grey; it contains numerous specks of mica, it does not effer- 

 vesce with acids, though the presence of lime is readily shewn by 

 chemical tests ; it is composed also of alumina and of a good deal of 

 oxyd of iron ; it adheres slightly to the tongue, and is friable when 

 immersed in water, it soon falls into a powder which is rather rough 

 and dry, it decrepitates on the first impression of the fire, becomes 

 hard, and when heated to redness, turns greyish-yellow. It forms a 

 bed of several fathoms in thickness on the south-western coast of the 



* Kirwan's Mineralogy, vol.ii. p. 61. 

 + Ditto vol. ij. p. 57. 



