part 1] THE SECTION AT WORMS HEATH. 



2. The Section at Worms Heath (Surrey). With Remarks 

 on Tertiary Pebble-Beds and on Clay-with-Flints. By 

 William Whitakeb, B.A., F.B.S., F.G.S., late of the Geo- 

 logical Survey. With Petrolooical Notes ly Gteoroe 

 MacDonald Daties, M.Sc, F.G-.S. (Bead April 9th, 1919.) 



Contents. 



Page 

 I. History and Literature of the Worms-Heath Outlier . 7 

 II. Description of the Section 9 



III. Remarks on the Blackheath Beds 11 



(a) London Basin. 



(b) Hampshire Basin. 



IV. Some other Eocene Pebble-Beds 14 



(a) Below the Blackheath Beds. 



(b) Above the Blackheath Beds. 



V. General Remarks on the above-described Beds 19 



VI. Remarks on the Clay-with-Elints 20 



VII. Petrological Examination of the Deposits 22 



I. History and Literature of the Worms-Heath 

 Outlier. 



The occurrence of outliers of the Lower London Tertiaries far 

 away from the main mass, in the Chalk-tract of Surrey, was known 

 to Prestwich, and the sites of some of them were noted by him, 

 though not in his papers read to the Society. 1 But, presumably 

 because he was then dealing with distance from the main mass 

 and not with size, these sites included only small patches, at 

 the top of the Chalk-escarpment of the North Downs and not 

 the much larger outlier with which we are especially concerned, 

 roughly a square mile in area and some way inward from the 

 Chalk-escarpment. 



All these outliers consist wholly of the uppermost of the three 

 divisions of the Lower London Tertiaries, to which the name 

 Blackheath Beds has been given, the underlying Woolwich Beds 

 and Thanet Beds being absent. This was not mentioned by Prest- 

 wich, who was dealing with the Lower London Tertiaries as a 

 whole and not with the divisions thereof, the details of which, 

 moreover, had not been then fully worked out, his third paper on 

 the Series not appearing until 1S54. 



The first recognition of the Tertiary tract of Worms Heath was 

 on Sheet 6 of the Geological Survey Map, published in 1861, 

 though the Surveyor (who need not be named) was mistaken as to 

 the age of the deposit when he first saw the place, some } T ears 

 before that date, the pebble-beds being taken as a peculiar kind 

 of Drift, rather than Eocene, until a greater knowledge of them, 



1 ' Water-bearing Strata around London ' 1851, p. 135. 



