Vol. 54.] EOCENE DEPOSITS OF DEVON, 235 



Great Haldon, the plateau-gravel, which here reaches a height of 

 over 800 feet, was re-examined. This gravel turned out to be 

 almost identical in composition with that of Black Down in Dorset. 

 It, also, is mainly composed of large boulders of ' annealed ' or 

 toughened Chalk-flint, weathered to a considerable depth and often 

 containing Upper Chalk fossils. Mixed with these is much Green- 

 sand chert, with radiolarian chert and veined Palaeozoic grits like 

 those so conspicuous farther east. At Haldon Palaeozoic rocks 

 are somewhat more common, in larger pieces, less worn, and 

 Purbeck rocks are naturally absent ; in other respects the Haldon 

 and Dorset gravels are of identical composition and appearance, 

 containing similar seams of white clay and rough quartz- sand. 

 The alteration of the large Chalk-flints to the core is an important 

 point, for in Pleistocene deposits the contemporaneous weathering 

 seldom extends to a greater depth than ^ inch. Eocene deposits, 

 on the other hand, always show a curious change in the pebbles, 

 which, even if only exhibiting conspicuous weathering to a moderate 

 depth, are annealed and toughened to the centre. The compo- 

 sition, general character, and position of the Haldon gravels all 

 point to their being of the same age as the gravels in Dorset 

 which, for reasons already given, ^ I consider to belong to the 

 Bagshot Series. 



The reference of the high-level gravel of Haldon to the Bagshot 

 Series naturally raises in a new form the question of the supposed 

 Upper Greensand age of the gravels surrounding the Tertiary basin 

 of Bovey at Combe, Milber Down, Wolborough, and Staple Hill. 

 Combe lies about 2 miles west of Little Haldon, and about the same 

 distance north of Kingsteignton. On the high road 5 mile south of 

 Combe Hill Cross a pit has been opened for road-material and 

 sand ; it shows : — 



Feet. 



Coarse gravel of well-rounded large Chalk-flints, toughened "^ 

 and weathered to the centre ; much small quartz ; Palaeozoic grits, | 

 coarse and fine; radiolarian chert (common), and red jasper )- 12 

 (one pebble) ; greenstone and ash ; Grreensand chert (one large | 

 block). ; 



Buff-coloured sand with much schorl 3 



The occurrence of rolled Chalk-flints and Greensand chert 

 makes it impossible that the gravel can be of Cretaceous age ; the 

 sand also corresponds in character with that associated with the 

 lignite of Bovey, not with the Cretaceous sand of Haldon. The 

 deposit agrees closely with the gravel capping Haldon, except that, 

 resting on Palaeozoic strata, and lying west of most of the Cretaceous 

 deposits, the proportion of old rock in the gravel is considerably 

 greater. 



The supposed outlier of Greensand at Milber Down yields similar 

 results, for the pits all contain varying quantities of Chalk-flint 



1 Op. yaw, ctY. pp. 491, 492. 



