INTRODUCTION". 29 



Saporta l have described several species of plants from strata of 

 Jurassic age, some of which are probably identical with English 

 species. Several of the ' species ' founded by Saporta on extremely 

 small fragments possess but little value as definite specific types, 

 and it is impossible to form any accurate estimate of the number of 

 East Yorkshire types which may be represented in the Portuguese 

 flora of Jurassic age. 



Equisetum lusitamcum, Heer, figured by Heer and Saporta, may 

 be identical with Equisetites columnaris, and Otozamites angusti- 

 folim, Heer, agrees fairly closely with some of the English examples 

 of Williamsonia pecten (Phill.); among the fragments referred by 

 Saporta to SpJienopteris there are some which recall Coniopteris 

 hymenophylloides and C. quinqueloba ; but it is useless to attempt 

 to base any detailed comparisons on such imperfect data. 



SCANDINAVIA. 



The Rhsetic flora of Scania, in Southern Sweden, contains several 

 species which are closely allied to Lower Oolite types. Nathorst's 

 memoirs on the plants from Palsjo, Bjuf, Helsingborg, and other 

 localities in Scania, are among the most important contributions 

 to our knowledge of Lower Mesozoic floras, and they enable us 

 to obtain a fairly comprehensive view of the characteristics of 

 Rhretic vegetation. Nathorst has himself drawn attention to the 

 numerous points of contact between the Rhaetic flora of Sweden 

 and the later flora of East Yorkshire. 2 The following list includes 

 such species from Nathorst's lists as best illustrate the existence 

 of a Lower Oolite facies in the Swedish flora ; for further 

 information regarding the Scanian plants reference must be made 

 to Nathorst's memoirs, from which the following species have been 

 selected : 3 



Rhtzomopteris Schenki, Nath. Not represented in the British flora, but worthy 



of note as possibly the rhizome of Dictyophyllion. 

 Cladophlebis nebbensis (Brongn.) \ 



C. Heeri, Nath. | cf. Ciadophlebis denticulate, (Brongn.). 



Asplenites, sp. 



1 Saporta (94), vide also Sharpe (50). 



2 Nathorst (80), p. 82. 



3 Nathorst (78 l ) (78 2 ) (78-86). 



