1 (5 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 20, 



fts would be expected to bo brought to and deposited in a lake * by 

 a river tio^ving• over decomposed granite. A common variety of 

 granite is frequent in Devonshire and Cornwall, containing — 



Silica 73-04 



Alumina 18-83 



Potash 8-51 



Magnesia 0*83 



Lime 0-44 



Oxide of iron 1*73 



Fluoric acid 0-18 



By looking at the above-mentioned plan of the basin, it will be 

 seen that the clay is continuously deposited in the valley leading to 

 Torquay ; therefore, if a lake once existed, in order to deposit the 

 clay, the current must have run in the direction of Kingskerswell 

 and Torquay, and did not, as now, find an exit to the sea by the way 

 of Teignmouth. 



In corroboration of this view appears the striking fact, that, were 

 the opening in the chain ofc hills surrounding the basin between the 

 hills in the rear of Hackney and Buckland Point (now allowing 

 the Eiver Teign and other streams to escape to the sea by the way 

 of Teignmouth) filled up, the water would accumulate until an ex- 

 tensive lake would be formed, having its outline indicated by the 

 dark line around the margin of the basin on the plan, and discharg- 

 ing its surplus water at the point where now stands Lawe's Bridge, 

 taking the road over the railway above the Torr Station ; from this 

 point the water of the lake would flow, with a rapid current, through 

 a well-marked channel still existing for some distance, past the Torr 

 Eailway-station, and at the foot of the site of Torr Abbey, to the sea 

 in Torbay. 



The height of this bridge above the mean level of the sea (as 

 kindly communicated to me by Mr. Appleton, siuweyor, of Torquay, 

 and taken by him for the Tbrquay Water-supply) is 171 feet ; but, 

 on examining the nature of the ground around this bridge, it is found 

 to be an accumulation of red brick- earth, evidently washed from 

 the immediate neighbourhood, — no doubt choking up the ancient 

 channel of the river for some considerable depth, certainly for 18 or 

 20 feet, as seen in the cutting below the bridge. Deducting 20 from 

 171, we have 151 feet for the height of the surface of the lake 

 above the mean level of the sea. Now this agrees remarkably well 

 with the physical features of the basin. I refer to the fact, that the 

 outline of the lake at that height nearly indicates the outline of the 

 Bovey deposit, no marked member of the deposit being found above 

 that line f ; and also that many of the hills forming the margin of 



* That the area of Bovey-Heathfield and Bellamarsh was once a lake was 

 argued by Mr, Godwin-Austen in 1834 (Geol. Proceed, vol. ii. p. 103): the 

 upper accumulation (" Head') alone, however, was supposed to be referable to 

 such a condition ; the lower sands and clays, which are destitute of chalk-flint 

 detritus, not being included in that lacustrine series, but (at least those near 

 Newton) referred to the Cretaceous series by Mr. Godwin- Austen, Geol. Trans. 

 he. cit. p. 4.51.— Ed. Q. J, G. S. 



t The highest part of the deposit is 151 feet above the mean level of the sea, 

 on Knighton Heatli. 



