XXX] V INTRODUCTION. 



In 1903 Geikie writes : " Of the total assemblage of fossils 

 in the ' Lower Greensand/ only a small proportion passes up 

 into the Upper Cretaceous formations, except among foraminifera. 

 . . . .This marked palaeontological break, taken in conjunction 

 with a great lithological change, and with an unconformability 

 which in Dorset brings the Gault directly upon the Kimeridge 

 Clay, shows that a definite boundary line can be drawn betwet-n 

 the lower and the upper parts of the Cretaceous system in the 

 south of England." 



This is in agreement with the more recent and exhaustive 

 classification of Haug (1910), who divides the Cretaceous system 

 into three main divisions, as follows in which the APTIAN (our 

 Lower Greenland) comes in the EOCRETACEOUS : 



( Panien. 

 j Maestrichtien. 

 Neocretace. \ C;imj>;mien. 

 I Santonien. 

 1 Coniacien. 



{Turonien. 

 iiaiiien. 

 Albien. 



r Al'TIKS. 



.A Barmnipn. 



Eocretace. \ . 



Hauterivien. 



I Valauginien. 



Historical accounts of the Englisli Lower Greensand will be 

 found in llolloway 1724, who describes the Fuller's Earth of 

 Woburn, Mantell 1S22, Coinheaiv fc Phillips 1^2, Fitton 

 1827, Mantell 1828 (35), Martin 1*28, Mantell LS:M, Fitton 

 1836, Mantell 18)39, 1844, 1847, Ibbetson & Forbes 1844, 1*4.-,. 

 In the last-named papers the authors gave an exceedingly 

 detailed account of the beds of the Lower Greensaiid, which 

 remained the standard for many years. 



In 1845 Fitton proposed the term Vectine for the Lower 

 Greensand beds, because of their special development in the 

 Isle of Wight. In 1847 he published a detailed and exhaustive 

 paper on the subject. 



Further accounts of the Lower Greensand will be found in 

 Dixon I860, Mantell 1851, Bensted 1802, Bristow 1862, Judd 

 1S71, Topk-y 1875, "Dixon 1878, and Etheridge 1885. Jukes- 



