422 Reviews — Rev. R. Ashiugton Bullen — Harlijn Bay. 



appear to be absent in the Eorest of Dean, so that the unconformity 

 in question is of considerable importance." ^ 



Tlie unconformity between the Coal Measures and the Lower 

 Carboniferous rocks in the Forest of Dean represents a great gap in 

 the Carboniferous succession. Tlie break appears to be quite as 

 extensive as that which Mr. E. E. L. Dixon has shown to exist 

 in the Titterstone Clee Hills,- and it is doubtless due to the same 

 earth-movement. The tectonic relations of the strata in both the 

 Forest of Dean and the Titterstone Clee Hills, show clearly that 

 a ])owerful earth-movement occurred at some date between Avonian 

 and Upper Coal Measure times. 



It would be premature to attempt any discussion of the bearing of 

 this evidence upon the general tectonic history of Carboniferous 

 times. But in this connexion it is important to note that future 

 research in the Bristol and Somerset Coalfields maj^ enable us to fix 

 accurately the date of the eartli-movement in question. A feature 

 which may prove to be of great significance is the relation of the 

 Pennant Grit to the Carboniferous Limestone in the Clevedon and 

 Clapton district, near Bristol. In 1905, Dr. Vaughan expressed the 

 opinion ^ that a considerable unconformity between the Coal Measures 

 and the Carboniferous Limestone afforded the only possible explanation 

 of the structure of that district. 



I?,E!"^IEAArS. 



Prehistoric Remains in Cornwall. 

 I. — Harlyn Bay and the Discoveries of its Prehistoric Remains. 

 By the Rev. R. A.shington Bullen, F.L.S., F.G.S. Third edition, 

 pp. 173. Harlyn Bay : Colonel Bellers, 1912. Price Is. net. 



HARLYjS" Bay lies to the east of Trevose Head in Cornwall, 

 the Avestern horn of the bay being formed by the corapai'atively 

 hard greenstone (proterobase) of Cataclews Point, and the eastern 

 side by Upper Devonian Slates. The southern and south-western 

 portions of the bay are bordered by Blown Sand, which extends 

 to Constantine Bay, thus isolating the headland of Trevose. As 

 remarked by Mr. Clement Reid, " At Constantine the sand drifts 

 right across the isthmus into Harlyn Bay, where it has overwhelmed 

 an ancient British cemetery . . . The graves at Harlyn are partly 

 dug in blown sand, but they have been overwhelmed by a much 

 thicker sheet of similar material." * 



We commence with a reference to the recent Geological Survey 

 publications, as the attention of Mr. Bullen has evidently not been 

 drawn to them. The first edition of his work was issued in 1901, 



^ E. A. Newell Arber, " On the Fossil Flora of the Forest of Dean Coalfield 

 (Gloucestershire), and the Kelationships of the Coalfields of the West of England 

 and South Wales " : Phil. Trans. Roy. Soc, vol. ccii, B, pp. 270, 277, 1912. 



- Geol. Mag., Dee. V, Vol. VII, p. 458, 1910. 



^ Q.J.G.S., vol. Ixi, p. 228, 190.5. 



* " Geology of the Country around Padstowand Camelford," 1910, p. 89, and 

 Geological Survey Map, No. 33-3, 1910. 



