210 HIDDEN BEAUTIES OF NATURE 



if fossil-hunting expeditions and rambles in search 

 of seashore treasures were more the order of the day. 

 Such a ramble as this will cure an attack of indi- 

 gestion in quicker time than the best medicine in a 

 chemist's shop. 



Commencing operations immediately to the east 

 of Folkestone Harbour in the greensand beds, we 

 soon find some good specimens of a fossil bivalve 

 known as rhynconella. Every line of the original 

 shell is perfect, although no trace of their former 

 shelly composition can be detected. All has been 

 replaced by brilliant iron pyrites, which give the 

 fossils the appearance of gold. The gault bed close 

 by, nearly ninety feet in height, supplies us with 

 some good crystals of selenite, a transparent variety 

 of gypsum or alabaster, a rock which, when found in 

 large quantities and then burnt to expel the water, 

 leaves a powder known as plaster of Paris. The 

 crystals we have found in their natural condition 

 split into thin leaves, thinner than ordinary note- 

 paper, and are used by microscopists for producing 

 beautiful polariscopic effects. When you become 

 acquainted with the uses of the polariscope you will 

 appreciate the beauty of these selenite crystals much 

 more than you can at present. 



We must not leave Copt Point, the scene of our 

 gault bed, without ' extracting ' from it specimens of 

 the following fossils : natica, belemnites, ammonites, 

 hamites, crabs and inocerami. Owing to the fragile 

 nature of these fossils, it is necessary to take out with 



