March 14th, ISg8^^ PROCEEDINGS. xxvii 



The President read a paper on " The Composition and 

 Structure of Spore- Coals and Bogheads," illustrated by 

 hand spedmens and thin sections under the microscope, by 

 which the fundamental characters were shown which distinguish 

 spore-coals and the class of oil shales known as bogheads. The 

 differences which present themselves were shown to be mainly 

 due to the original plant organisms of whose fossiHsed remains 

 the spore-coals and bogheads were composed. The " better- 

 bed " coal of Bradford and the Tasmanite mineral of Tasmania 

 were selected as examples of coals owing their special properties 

 to spores, or to the reproductive organs of certain cryptogamic 

 plants of doubtful origin, but whose probable relationship is 

 considered by Sir William Dawson to be with the Rhizocarpese. 

 On the other hand, the combustible part of bogheads, such as 

 the Torbane Hill mineral of Scotland, the boghead of Autun in 

 France, and the kerosene shales of Australia, owed their remark- 

 able properties to the vast accumulations of microscpic algae of a 

 very low order, and so far as is yet known, without any actual 

 Hving representatives. Science is indebted for the latter facts 

 to the long-continued investigations into the nature of bogheads 

 carried on by Professors Renault and Bertrand in France. 



Mr. Mark Sykes made a short communication on mimetic 

 forms among Lepidopterous insects, showing some fine charac- 

 teristic specimens of the genus Kalli?7ia, including K. inactus^ 

 K. paralekta^ K. albofasciata^ K. philarchus^ and K. Wardii^ 

 from N. and S. India, Siam, Java, Ceylon, and the iVndaman 

 Islands. 



Mr. Allen exhibited some specimens of an alloy of man- 

 ganese and silver. 



Mr. Broadbent described Sarcina, an organism observed by 

 him in manure water. 



