THE JURASSIC FLORA OF SUTHERLAND. 703 



The Culgower flora has many features in common with the Upper Jurassic (Wealden) 

 flora of Spitzbergen, the Wealden of England, Germany, and other regions, as also with 

 the older Jurassic flora of East Yorkshire which may be taken as a type of Middle 

 Jurassic floras in various parts of the world. As one would expect in a flora of 

 Kimeridgian age, we find an admixture of Wealden or Upper Jurassic, Middle, and 

 Lower Jurassic species. 



The investigation of the Sutherland Kimeridoian flora reveals facts which are of 

 greater interest from a botanical than from a geological point of view. During the closing 

 stages of the Jurassic era there flourished in the north-west of the European continent 

 a flora which extended into Arctic latitudes : many of the genera which were then 

 prominent no longer exist, but others have left descendants in tropical and sub-tropical 

 floras of the present day. Hausmannia is no doubt closely related to the Indo-Malay 

 fern Dipteris ; Laccopteris and Matonidium may be said to survive in the Malayan 

 genus Matonia ; in G-leichenites we have a type now represented by the recent species 

 of Gleichenia in the southern tropics and south temperate regions ; Todites and 

 probably Cladophlebis denticulata are links with Todea barbara of South Africa and 

 Australia. The Cycadean species, which were conspicuous in the Culgower flora, are 

 connected, more or less closely, with the dwindled family of Cycads, which is now 

 mainly tropical in its distribution. Araucarites and, in all probability, Elatides curvi- 

 folia have their nearest allies in the Norfolk Island Pine (Araucaria exceha) and other 

 species of Araucaria in Eastern Australia, New Caledonia, and adjacent regions. The 

 botanical data collected by Marcus Gunn and others from the Upper Jurassic rocks 

 of Sutherland furnish evidence of striking changes in the geographical distribution 

 of several generic types which have persisted through the ages. 



The more experience one has in the determination of fragmentary fossil plants, the 

 less confidence one feels as to the value of attempts to draw fine specific distinctions. 

 I am well aware that some of my determinations rest on a basis which is far from satis- 

 factory ; I have, however, endeavoured to keep under control the temptation to read 

 into the imperfect records more than they contain. The task of deciphering or piecing 

 together the disjuncta membra of this Kimeridgian flora has not been easy ; but to the 

 interest inseparable from a study of an ancient flora, there has been added the satis- 

 faction of doing what I could to produce a contribution to British Mesozoic Botany 

 which might be worthy of dedication to the memory of Marcus Gunn. 



