BOTA 



Geology of Rochester District. 



IN any serious attempt to obtain an intelligent knowledge and 

 understanding of the characteristic peculiarities of any district the 

 first and most important step must be a more or less close study 

 of its geological structure, which is the chief determining factor in its 

 Scenery, Meteorology, Flora and Fauna. To facilitate such study the 

 following Geological Sketch, largely drawn from The Geology of the 

 Thames Basin (Whitaker), has been prepared, showing the various 

 strata occurring in our District, and indicating places where they may 

 be seen and studied. 



Though so limited in area, our District includes a wide range 

 of surface rocks, representative of the various geological formations 

 extending from the Lower Greensand (Secondary or Mesozoic Period) 

 to the Lower Eocene (Tertiary or Cainozoic Period), with local patches 

 of High and Low Level Gravels and Alluvium (Recent). The surface 

 soil, resulting in the main from the disintegration of the very varied 

 underlying rocks, is of course itself also very varied, and as plants 

 have been gradually modified in such a manner as to fit them severally 

 for life in certain kinds of soil and situation in preference to others, the 

 number of species inhabiting the District will be proportionally very 

 large and varied. The effect of varied rock-surfaces on the number 

 of species and their distribution is well shown by the following table 

 from Brewer's Flora of Surrey.'^ I am not aware that such a table has 

 been drawn up for Kent, but as like causes produce like results we 

 may safely take this as a fair guide to the mode of distribution of the 

 Flora of Kent. 



The number of species recorded as having been found in the county (Surrey) 984 



occurring on all formations (j.^., common to all) .. 117 



supposed to be confined to the Valley Alluvium .. 7 



,, ,, Superficial Gravels .. 19 



,, ,, Bagshot Sands .. .. 9 



,, ,, London Clay .. .. 14 



,, ,, Woolwich & Reading Beds 2 



,, ,, Thanet Sand .. .. o 



Chalk 55 



,, ,, Upper Greensand & Gault 5 



,, ,, Lower Greensand .. .. 28 

 ,, ,, Weald Clay & Hastings Beds o 



"Quoted by Whitaker in The London Basiti. 



