part 1] SANDS A^D GRAY ELS AT LITTLE HEATH. 4£ 



direction for a quarter of a mile in width. The} r originally covered 

 a much larger area. 



They appear to be of marine origin, and to have been deposited 

 as, and in association with, tidal beaches in comparatively shallow 

 water. They were not deposited until the London Clay and 

 Heading Beds- alike had been denuded from the area that they 

 cover, and are therefore considerably post-Eocene in age. It may- 

 be added that they appear to be uniform with the Pliocene beds, 

 south of the Thames, and this, supported by other considerations, 

 suggests that they are of Pliocene age ; further, their similarity 

 to the High-Plateau Gravels suggests their contemporaneous, 

 deposition also with these gravels. 



If this inference be correct, it follows that the High Plateau- 

 Caravels are also of Pliocene age and of marine origin. 



They are persistently overlain by Griacial deposits, which have 

 moreover ploughed into and disturbed them throughout the area. 



I desire to express my sincere thanks to Mr. George Barrow for 

 the great interest that he has taken in these deposits, and for his 

 valuable assistance throughout my investigations; to Mr. J. F. X. 

 Green, to Mr. W. Humphrey, and to others who have given me the 

 benefit of their experience and the particulars of well-sinkings in 

 the neighbourhood; to Mr. W. R. Locke, the capable Surveyor 

 of the Hemel Hempstead District Council, who has had charge 

 of the workings, and his foreman, Mr. J. Smith, both of whom 

 have assisted me in many ways, and especially in enabling me- 

 to obtain a complete section of the beds down to the Chalk. 

 And, finally, to Mr. A. A. Barron and Mr. J. T. Newman for 

 the photographs that have been used in illustration of this paper. 



EXPLANATION OF PLATES II & III. 



Plate II. 



Eastern side of the pit at Little Heath. On the right are seen High-Level 

 Gravels overlain by loamy sands. On the left are Glacial beds (clay 

 with pebbles) introduced by a superficial fault. (See pp. 33, 36.) 

 Photograph by Mr. J. T. Newman. 



Plate III. 



Western side of the pit at Little Heath. Gravels on the left ; Glacial beds,, 

 introduced by ice-thrust, on the right. These Glacial beds underlie the 

 clay with pebbles. (See p. 35.) Photograph by Mr. A. A. Barron. 



