PLORA OF THE BAGSIIOT FORMATION. 



15 



Alum Bay, are said to bo " identical," and a little further on these places are said to be 

 " on exactly the same horizon," although their relative positions had long previously been 

 pointed out by Prestwich and others. The determinations and correlations are very 

 incorrect, probably from the specimens being mixed, since of 22 species from Bourne- 

 mouth, 13 are said to be identical with those of Alum Bay; but we now know that 

 none of the characteristic forms are common to both horizons. Palms are said to be 

 met with only at Corfe ; yet two species are included in the list of fossils from Alum 

 Bay, in the body of the work, at p. 42. This memoir does not include any species not 

 published in De-la-Iiarpe's previous work; an addendum contains a rough list from 

 Heer of the genera found in the Miocene of Oeningen, which has no apparent con- 

 nection with the subject. 



In 1865 W. S. Mitchell,^ who for some time previously had been working at 

 the Lower and Middle Bagshot Beds, figured a species of Poraiia, which he pro- 

 visionally named P. Vedensis. lie also noticed various new leaves, to which, however^ 

 he declined to attach either generic or specific names. In 1806" he again announced 

 the discovery of further leaf-forms at Alum Bay, without offering any opinion as 

 to the number of species obtained. Some 470 specimens had been collected, and 

 drawings of some were exhibited to the British Association.^ Two years later G, Maw*' 

 expressed the opinion that the Porana of Mitchell, and another flower-like form from 

 Studland, resemble Kydia more than Porana. In 1809 A. Wanklyn described frag- 

 ments of a Gleichenia from Bournemouth, for which he proposed a new genus and two 

 species. In 1870 Mansell-Pleydell noticed the occurrence of plant-remains at Alum 

 Bay, Studland, &c., especially mentioning Gleichenia and Sahal. 



From this time little has been written except the few brief notices in which 

 I have quite recently called attention to the unexpected extent of the Bagshot floras 

 of Hampshire and Dorsetshire. These will be found in the ' Reports of Conferences 

 held in connection with the Loan Collection of Scientific Apparatus in 187G, Section 

 of Physical Geography, &c.,' p. 412; in the text of a lecture given in the latter part of 

 1876, at the South Kensington Museum in a paper read before the " Geologists' 

 Association," January 5th, 1877, published in the fifth volume of their 'Proceedings;' 

 in subsequent papers in ' Nature,'^ and in an article in the ' Popular Science Review ' for 

 July, 1878. 



In Prof. Rupert Jones's second edition of Dixon's ' Geology of Sussex,' 1878, p. 162, 



1 'Geol. Mag.,' vol. ii (186.5), p. 516, figs. 1—3. 



3 .Geol. Mag.,' vol. iii (1866), 476. 



3 <■ Report Brit. Assoc.,' 1866, p. 146. 



* ' Geol. Mag.,' vol. v (1868), p. 74. 



s 'Ann. and Mag. Nat. Hist.,' ser. iv, vol. iii, p. 10, pi. i. 



« ' Flora of Dorset.' 



7 ' Nature,' January 11th, 1877, and following week. 



8 March 29th, August 9th, November 15th, 1877, &c.. 



