330 MR. A. J. JUKES-BROWNE ON [^-Ug. I904, 



general southerly inclination of Salisbury Plain, of the Dorsetshire 

 Downs, and of the Blackdown Hills. Judging from the elevation 

 of the Older Pliocene deposits in Kent, this change did not take 

 place till later Pliocene time. 



The local change was, of course, the formation of the Bovey 

 syncline ; and there is nothing to tell us exactly when this was 

 formed, whether in Miocene times during the general elevation 

 of the Anglo-Gallic region, or whether it was coaeval with the 

 uplifts of later Pliocene time. I may here point out that I do not 

 regard the synclinal flexure as confined to the Bovey Basin, but think 

 that this basin is only a local downward bulge in the course of a 

 much longer synclinal axis. The curious plain or depression in the 

 granitic area around North Bovey and Moreton Hampstead, where 

 over a tract of about 6 square miles the average level is only 

 800 feet above the sea, and the communication between this and 

 the still lower basin near Chagford, of which mention has previously 

 been made (p. 319), are in a line with the Bovey Basin, and their 

 existence can be understood if they are regarded as due to a north- 

 westerly extension of the Bovey syncline. 



Still farther to the north-west, between Hatherleigh and Marland, 

 there is a tract of clay, sand, and gravel unconnected with any 

 modern river-valley ; and Mr. \V. A. E. Ussher informs me that these 

 deposits bear a strong resemblance to the Bovey deposits. They 

 may, therefore, be of the same age ; and it is a curious fact that a 

 prolongation of the north-western axis above indicated would 

 include this tract. It is also noteworthy that such a line is roughly 

 parallel to the watershed which runs across Devonshire, from a 

 point south of Hartland on the north-west to Tor Bay on the south- 

 east. 



Returning now to the Yalley of the Teign, let us consider the 

 effect which the general tilting and the local flexure might have 

 had upon the streams that we have supposed to exist in Oligocene 

 times. Neither change could have had much effect upon the course 

 of the Upper Teign flowing eastward from Dartmoor to the Exe ; 

 but both changes would have a strong effect upon all streams which 

 ran from north to south, for, by increasing the fall of the ground, 

 they would increase the velocity and the erosive power of the 

 streams. 



Such would be the case with the stream which I have called the 

 Lower Teign, and have supposed to be a tributary of the river 

 that flowed eastward through the Teignmouth Yalley. This little 

 stream was doubtless carving out a valley between the Haldon Hills 

 and the granitic area west of Christow and Hennock throughout 

 Oligocene and Miocene times. The gradual sinking of the Bovey 

 Basin, and the increasing slope thus given to its watercourse, 

 would cause it to deepen the higher part of its valley, and its upper 

 tributaries would cut back deeply into the watershed separating it 

 from the valley of the Upper Teign. 



If that portion of the Teign Valley which lies between Dunsford 



