A SURVEY OF THE LOWER TEES MARSHES 121 



Works vvliere the appearance of higher natural banks (now 

 showing signs of erosion) admits of the approach of cultivation 

 to the very water edge. 



The entire surface of both is broken up by a maze of 

 intricate winding channels and an abundance of pools or pans. 

 As in Saltholme, the remains of saltworks of bye-gone days 

 persist in the shape of detached mounds — one of which is 

 utilised as a garden ! 



Of the two divisions, that to the south offers by far the 

 most valuable opportunities for study both by virtue of its 

 superior area and of its freedom from human interference. 



Its Tides and Channels. 



So deep is the main creek, and so steep are its banks, that 

 only the very highest spring tides cover the whole surface, an 

 average high tide merely scouring the channels, and an 

 ordinary one barely entering them. 



Whilst the channels falling directly into the Fleet possess 

 fairly stable beds as nearly parallel to the- main stream as 

 possible — a circumstance depending on the general direction 

 of the tidal thrust— the secondary channels meander aimlessly 

 across the marsh, ever changing their courses as landslips and 

 similar trivial incidents determine. When such an event 

 occurs, the energy of the advancing tide, taking the line of 

 least resistance, soon scoops out a new path from the lower 

 levels between the hummocks, the irregular disposition of 

 which settles the sinuous course of the newly developed 

 channel, as it presses onward to attain the surface level of the 

 marsh, or to break into a depression pan. 



Casually formed as they are, in the end, nevertheless, they 

 serve to run off surface water, and thus a system of tributaries 

 essentially the same, but on a smaller scale, as the brook and 

 its feeders is set up, only to repeat the process of decay and 

 regeneration outlined above. 



Secondary Changes in Surface Configuration. 



Like all saltmarshes, Greatham Marsh is subject to erosion, 

 but its peculiar configuration renders it specially susceptible 



