A SURVEY OF THE LOWER TEES MARSHES Ql 



of these changes is confirmed by the presence of enormous 

 sub-fossil oaks of (geologically speaking) recent age. Further, 

 physical changes acting in the reverse direction from these, 

 are hinted at by the great masses of somewhat recent oyster, 

 mussel, and cockle shells lying at no great depth and even on 

 the surface in Greenabella Marsh. 



Two hundred years ago, the sandy estuary, with the mud flats 

 known locally as " slems," had an area approaching fourteen 

 or fifteen square miles. If attempts had previously been made 

 to reclaim portions of this tract they were of no significant 

 extent. The first really valuable reclamation attempted was 

 that of Saltholme and Cowpen marshes in 1740, this being 

 brought about by building a solid earth wall skirting Greatham 

 Creek, aided by one striking in a southerly direction from it. 

 Over a hundred years later, the erection of a massive slag 

 wall has completed the good work, resulting in all, in the gain 

 of about 26,000 acres of former salt marsh, now utilised* as a 

 valuable grazing ground for numerous cattle, and in part as 

 the site of valuable iron and salt works. 



Although the salt industry in its modern guise only dates 

 from 1862, when Bolckow and Vaughan, in boring for water, 

 struck the rock salt, it is a very ancient one locally, as the 

 name Saltholme indicates. Moreover, in documents dating 

 from the 14th and 15th centuries, frequent references point to 

 the manufacture of considerable quantities of salt here ; very 

 probably brine springs and sea water were used as sources. 



Relics of the old salt works are visible on all of the marshes 

 in the form of more or less irregular mounds which, until I 

 had grasped their precise import, puzzled me not a little. 



If one glances at Hewitt's (1832) Chart of Tees Bay, these 

 reclaimed tracts are represented as being intersected by 

 numbers of small streams ; even at that early date this was 

 incorrect, as the earth wall had completely deprived most of 

 these of direct access to the sea. Obviously, for the landward 



* This year (1918) extensive portions are being ploughed up in order to 

 grow grain and other food crops. 



