The River Smithford to Lyell 



When the wind is blowing strongly it will carry with 

 it grains of all sizes up to the maximum which a wind of 

 its particular velocity is capable of moving, and then as 

 the breeze subsides the coarser grains will be dropped 

 first and form a layer, after which finer and finer layers 

 will be formed as the disturbance slowly subsides. 



It seemed to be of interest to compare the red grains 

 observed in the Upper Greensand, and for this purpose 

 a number were picked out by hand from a crushed mass 

 of the rock. On being treated with hydrochloric acid 

 these were found to dissolve completely and to consist 

 entirely of oxide of iron ; our original view that they 

 represented grains of glauconite which had become 

 oxidized would, therefore, appear to be correct. 



The white sand from the Lower Greensand was 

 found on examination with the microscope to consist 

 largely of the small siliceous spicules which occur em- 

 bedded in the living tissues of sponges. 



We next turned our attention to the contents of the 

 hollow flints. On carefully washing these in running 

 water much of the fine dusty matter was removed, and 

 there remained a small heap of chalk granules, some 

 about the size of an ordinary pin's head and some 

 smaller. On applying the microscope we found the 

 granules to be minute shells of animals belonging to the 

 group of the Foraminifera, and amongst others the 

 genus Globigerina was recognized. These minute shells 

 are at present forming chalky deposits on the floors 

 of our great oceans beyond the limits reached by the 

 sand and mud derived from the waste of the land, and 

 as similar shells were to be seen in thin sections of the 

 chalk, it seemed not unreasonable to conclude that we 



