ZOOLOGY AND BOTANY 195 



tion of our islands during the Pleistocene glacial 

 period. The study of the distribution of the fossil 

 fauna and flora of the Coal Measures has had an 

 important bearing on the development of some of 

 our concealed coal-fields, rendering it possible in 

 some areas to determine the horizon of a stratum 

 by the study of the fossils obtained from a bore-hole, 

 and so to estimate the probable depth at which 

 a desired seam of coal would be encountered. The 

 systematic study of the fossil flora of the Jurassic 

 rocks of Yorkshire, started by a committee of the 

 Association, has been subsequently continued by 

 other means ; and the investigation of the Old Eed 

 Sandstone rocks of Rhynie, Aberdeenshire, involves 

 that of plant remains which constitute the oldest 

 known land flora. Lastly, reference is due to the 

 collection of photographs of geological interest, 

 which has been supported gratuitously by a very 

 large number of photographers, professional as well 

 as amateur, and has enabled the formation of series 

 of prints and slides which illustrate the various 

 physical features of the British Islands, and have 

 been extensively used for purposes of instruction in 

 universities and schools. 



ZOOLOGY AND BOTANY : EXPLORATION 



Out of all the zoological and botanical researches 

 with which the Association has been identified, we 

 may appropriately choose for chief notice those in 

 marine biology, because they have been so con- 

 sistently supported from the earliest years. Under 

 the auspices of a committee appointed in 1839, ' for 

 the investigation of British marine zoology by means 



