• HEMPSTEAD BEDS. 455 



These beds were classed as Lower Miocene by Sir Charles 

 Lyell, as Prof. Heer had recognized from them some species 

 of Plant-remains found also in the lignite of Bovey Tracey : that 

 deposit, however, is now regarded as Eocene.' The plants include 

 Cham, Sequoia, NymphcBa, Carpolithes, etc. 



A Bird, Ptenoniis, has also been found in the strata. The beds 

 consist chiefly of red and green mottled clays, marls, and shales. 

 The base of the lower Hempstead beds is marked by a " Black 

 Band " of carbonaceous clay, nearly two feet thick ; and that of the 

 middle Hempstead beds by a "White Band" of broken and entire 

 shells, 9 inches to 4 feet thick, which forms a conspicuous feature 

 in the cliffs. Panopcva Gibbsii occurs at the base of this White 

 Band, and this middle division has yielded remains of Hyopotamus, 

 besides Turtles, Fishes, etc.* 



PLIOCENE. 



The Pliocene deposits of this country occur chiefly in Norfolk 

 and Suffolk, and they consist of shelly sand, gravel, and laminated 

 clay. 



The term Icenian was proposed for these strata by Dr. S. P. Woodward, 

 because their order of succession was first determined in the Eastern Counties, the 

 country of the Iceni.^ 



The beds are subdivided as follows: — 



! Cromer Forest Bed Series. 

 Norwich Crag Series.* 

 Red Crag. 

 Older Pliocene. — Coralline Crag. 



Mr. S. V. Wood, jun., maintained that the Pliocene period properly inckided 

 the Glacial deposits, because in Norfolk we find a continuous succession of deposits 

 from the Crag and Forest Bed Series upwards into the newer accumulations.* 

 The term Pliocene is, however, generally confined to deposits newer than the 

 Miocene and older than the Glacial period, and in this sense it is here used. 



^ Q. J. xviii. 371 ; Lyell, Student's Elements, 1S71, p. 219; see also J. S. 

 Gardner, Q. J. xxxviii. 12. 



* Bristow, Geol. I. of Wight, p. 90. 



^ Manual of the Mollusca, p. 410. The term Subapennine was given by the 

 Italian geologist, G. B. Brocchi, to those Tertiary strata which lie on the lower 

 part of the Apennines on the sides both of the Adriatic and the Mediterranean, and 

 constitute the older Pliocene strata of Italy. Beds, however, of Miocene as well as 

 Pliocene age have been included under this term. The term Neogene was used 

 by Moriz Homes for the Miocene and Pliocene deposits. See Lyell, Elements of 

 Geol. ed. 6, 1865, p. 207. 



* The term Upper Crag has been used as a synonym for this series ; the term 

 Middle Crag was applied to the Red Crag by A. and R. Bell in 1S71 ; while the 

 Coralline Crag is sometimes known as the Lower Crag. 



* Q. J. xxxvi. 457 ; xxxviii. 667. 



