174 Notices and Extracts from the Minutes of the Geological Society. 



to sixteen inches in their transverse diameter. They split with ease trans- 

 versely, into slices of various thickness, and wherever they divide exhibit innu- 

 merable sharp casts and impressions of small bivalve shells, of which the calca- 

 reous matter has altogether disappeared. 



The author also states, that in sinking a well at Tunbridge Wells, at the 

 place called North Grove, a thin seam of coal was found at the depth of 50 or 

 60 feet. 



