68 AN EARLY NEOLITHIC KITCHEN-MIDDEN. 



the following observations were made, Lord Eldon having kindly 

 given permission for the necessary excavations. 



While staying at Corfe Castle I devoted most of my spare time 

 to collecting at Blashenwell. The immediate object in spending so 

 much time at that place was the hope that this fossiliferous tufa 

 might throw some light on the obscure history of the wide-spread 

 sheets of unfossiliferous gravel which cover so much of Dorset. 

 This result, unfortunately, was not attained, for the tufa proved to 

 be of later date than I at one time thought ; but on the other hand 

 it turned out to be exceptionally interesting as an ethnological 

 storehouse, as well as from the point of view of the naturalist 

 studying the origin of the existing fauna and flora of Dorset. 



Blashenwell is a farm lying about a mile-and-a-half south-south- 

 west of Corfe Castle at the foot of the ridge formed by the Purbeck 

 strata. The farm buildings are on Lower Purbeck, and the 

 intermittent calcareous spring, which formerly deposited tufa, rises 

 in the stone-beds of the Middle Purbeck, and flows across the 

 Wealden Beds into a brook which runs northward to Corfe. At 

 certain seasons the spring turns a mill at the farm ; at others it is 

 entirely dry. There is another marked peculiarity to which 

 attention must be drawn. The water, once so highly charged with 

 lime salts that they were at once thrown down, now seems never 

 to deposit calcareous tufa, though the water is still exceptionally 

 hard. After examining the spring at all seasons of the year I can 

 find no deposit, and, as will be shown, the formation of the tufa 

 apparently ceased before the Roman occupation. It is difficult to 

 say to what cause the change in character of this intermittent 

 spring was due, but it may be connected with the destruction of 

 the forests which once clothed the slopes above. 



One is inclined on first examining it to refer the tufa to some 

 period when the adjoining valleys were less deep ; but a closer 

 inspection shows that the sheet follows the existing slopes and 

 must have been deposited when the contour of the ground had 

 already taken its present form. Calcareous tufa is seldom thrown 

 down on a dead flat. It is deposited on slopes, or even on the 



