OHilEiiOD TALLEY OF THE lEIGX. 423 



in length into the vein at right angles to the side. Fragments from 

 the adjoining Carboniferous beds are imbedded in the elvan ; these 

 are sometimes not quite detached from the native rock, and for the 

 most part retain the angles ; in the larger veins the edges are occa- 

 sionally rounded, as if the mass had undergone attrition ; but the rock 

 does not appear to have undergone any change. Continuous partings 

 occasionally pass through both the elvan vein and the adjacent rock, 

 and such a parting has been found filled with a thin vein of schorl. 

 The elvan veins occasionally cut the quartz veins of the Carboniferous 

 beds. 



Xo traces of undoubted glacial action have been seen in this dis- 

 trict. In examining the gravels a frequent cause of error exists in 

 the great similarity between the disintegrated, or partially decayed 

 portions of granite rock in situ, and the slightly moved angular 

 fragments that form the contour or surface-gravel ; and as a general 

 rule no bed can be regarded as a " granite gravel*' which does not 

 contain fragments that have been evidently rolled or transported. 

 Again, the rounded form of blocks of granite is no evidence of their 

 having been transported, as the gradual decay of the rock not mi- 

 frequently exposes its spheroidal structure, and a rounded mass is 

 seen which at first sight has the appearance of a rolled block. As 

 the gravels lying at the bottom of the valleys near Dartmoor have, 

 it is believed, been all disturbed in the process of streaming for tin, 

 no deductions have been di'awn from them. In the gravels that will 

 be noticed, no animal and, with the exception of the trunks of trees 

 found in one instance in the " contoui' gTavel," no vegetable remains 

 have been found. 



Certain small detached patches of gravel, composed of fr'agTuents 

 of transported rocks, occur on the Carboniferous beds and granite ; 

 these have been regarded as the remains of beds deposited before 

 the reexcavation of the valleys, and are here called the " Old Gra- 

 vels." Proceeding dovm the valley of the Teign, these " Old Gravels " 

 may be noticed at the following places : — By the road-side above 

 Gidley Castle, about 900 feet above the sea-level, angular and 

 rolled blocks, of various descriptions of granite and granitoid rocks, 

 are exposed in a cutting, and are partly formed into a conglomerate 

 by a bed of clay. Near the bridge in Gidley Park, on the hill-side on 

 the left bank of the river, about 680 feet above the sea-level, there is 

 a deposit formed of fine granite or granitoid gravel mixed with rolled 

 and angular fragments of transported granite and elvan, the deposit 

 being occasionally in laminae, and the bed exposed about 25 feet 

 in thickness. Beds of gravel are seen in the section in the river- 

 bank near this place ; but it is uncertain whether these are part of 

 the last-named bed. On the left or western side of the valley of the 

 Week Brook, near Tellum (Elm of the Ordnance Siuwey), about 700 

 feet above the sea-level, a bed of " Old Gravel " composed of rolled 

 and angular blocks of various kinds of granite, quartz rocks, angular 

 vein-stuff, and schorl is seen ; and near Bughead (815 feet above the 

 sea-level) similar transported fragments, overlying a bed of disinte- 

 grated granite in situ, existed in a cutting by the side of the high- 



