Vol. 62.] ANNIVERSARY ADDRESS OF THE PRESIDENT. CXX111 



500 feet above the main valley, descends at Hobgrumble Gill to 

 join it. Sections along Bleaberry-Tarn valley and Gillercombe 

 are drawn to true scale, vertical and horizontal, in figs. 10 & 11 

 (pp. cxxi & cxxii). 



It will be seen that many of the valleys of the district have been 

 deepened by 500 to 1000 feet since the time when the tributary 

 valleys had grades adjusted to those of the main valleys— a very 

 appreciable proportion (in some cases considerably more than one 

 third) of the entire depths of the valleys. 



YI. Depression of the Outskirts of the District. 



At the time of the deepening of the main valleys with the 

 production of hanging valleys, the country must have stood much 

 higher than it does at the present day, and was probably connected 

 with the Isle of Man, St. George's Channel being then dry land. The 

 exact height above present level is unknown, but various buried 

 valleys filled with Drift give some indication of the minimum 

 height. 



In the Memoirs of the Geological Survey, Explanation of Quarter- 

 Sheet 91 N.W. (the southern part of the Furness District), is 

 a record of a boring at Park House Iron-mine near Dalton-in- 

 Furness, where 537 feet of ' pinel ' (Glacial Drift) was pierced before 

 the solid rock was reached, the top of the bore being about 150 feet 

 above sea -level, and rock occurring at the surface at no great 

 distance on either side. 



At this time the submergence of the Morecambe-Bay depression 

 and the Solway portion of the Eden-Valley depression must have 

 occurred ; and in the former area the old valleys which were, as 

 already stated, formed along wedge-like masses of Carboniferous 

 rocks let down among the Lower Palaeozoic rocks, were converted 

 into the estuaries of the Duddon, Leven, Winster, and Kent. These 

 estuaries have since been largely silted up and converted into the 

 peat-mosses which, backed by the Lakeland fells, form so promi- 

 nent a feature of the southern part of the district. 



More oscillations have since occurred, which are indicated by the 

 raised beach near Silverdale, but these are not important as bearing 

 upon the general features of the district. If the uplift of the dome 

 occurred chiefly in Miocene times, and the depression in pre-Glacial 

 times, this would limit the chief period of formation of the valleys 

 of Lakeland to Miocene and Pliocene times. 



