416 SPECIAL GEOLOGY. 



COAL OF THE OOLITE. In the district north of the 

 Humber, the lower beds of this formation assume a new 

 character, and the forest marble and great oolite are replaced 

 by beds of sandstone, shale, and carbonaceous matter. The 

 coal, though greatly inferior both in quality and extent to 

 that of the carboniferous group, never exceeding sixteen 

 inches in thickness, is of considerable local value. Fossil 

 plants are found in the sandstones which accompany the 

 coal : and in Gristhorpe Bay a seam of shale 'is traceable for 

 a considerable distance, containing leaves of ferns, Eauiseta, 

 Cycadece, &c., specimens of which are in the British Museum. 

 A similar deposit of coal was discovered at Brora, in Scotland, 

 and was worked, from patriotic motives, by the late Duke of 

 Sutherland ; but, from the great loss incurred thereby, the 

 works are now given up. 



EXEECISES 



ON THE OOLITIC GROUP. 



1. State the derivation of the term oolite. 



2. Describe the general geographical distribution of 

 these beds. 



3. Name their localities in other countries. 



4. Mention the chief authors and collections. 



5. Describe the principal characteristics of the group. 



6. Point out the sub-divisions of the beds. 



7. Mention their respective mineral characters. 



8. State their principal fossil remains. 



9. Describe any fossil objects of extraordinary nature and 

 interest which have been discovered in this group. 



10. Trace on a map and commit to memory the general 

 direction of the strata, and name the counties in which 

 they occur. 



11. Mention their economical and commercial relations. 



12. State any facts of a generally interesting and in- 

 structive nature connected with this group, and consult the 

 foregoing epitome for questions and answers on the principal 

 features of its history. 



