ABSTRACTS OF LECTURES. 69 



measure times, organisms of the same class may have con- 

 tributed to the conversion of wood into coal. Bacteria, 

 fungi, and algae are by the microscope found to occur 

 frequently in coal, and Renault regards bacteria as capable 

 of producing all the necessary chemical changes. 



The concluding part of the lecture dealt with some of the 

 plant remains found in coal and in the coal-measures, special 

 reference being made to the aid which the microscope has 

 given to the discovery of the structure and relationship of 

 the interesting plants (i) Sphenophyllum, forming a link 

 between the horsetails and the lycopods, and (2) Lygino- 

 dendron, forming a link between the ferns and the cycads. 



The lecture was illustrated with a number of lantern slides, 

 some of which were kindly lent by Prof. Lebour. 



