Palaeontologie. 47Q 



One of the most striking facts afforded by a study of the 

 Mesozoic fern Vegetation is the former extension and vigorous 

 development of two families, the Dipteridinae and Matonineae, 

 which are now confined to a few tropical regions and repre- 

 sented by six species. The fertile fragment of a frond of 

 Matonldium exposed by a stroke of the hammer in a piece of 

 iron-stained limestone picked up on the beach at Haiburn 

 Wyke (a few miles north of S carbo ro u gh), is hardly distin- 

 guishable from a pinna of the Malayan Matonia pedlnata. 

 Rhaetic and Jurassic ferns referred to the genus Laccopteris 

 afford other examples of the abundance of the Matonineae in 

 the northern hemisphere during the earüer part of the Meso- 

 zoic era. 



The modern genus Dipterls, with its four species occurring 

 In India, the Malayan region, Formosa, Fiji, New Cale- 

 donia, Stands apart from the great majority o\ Polypodiaceous 

 ferns, and is now placed in a separate famiiy — the Dipteri- 

 dinae. Like Matonia it is essentially an ancient and moribund 

 type with hosts of ancestors included in such Rhaetic and 

 Jurassic genera as Dictyophyllum , Caniptopteris, and others 

 which must have been among the most conspicuous and vigo- 

 rous members of the Mesozoic Vegetation, 



Flowering Plauts. Our retrospect of the march of plant- 

 fe has so far extended to the dawn of the Cretaceoiis period. 

 a chapter in geological history written in the rocks that consti- 

 tute the Wealden series of Britain exposed in the Sussex 

 cliffs and in the Weald district of south-east England. One 

 interesting fact as regards the composition of the Jurassic Flora 

 is the absence of any plants that can reasonably be identified 

 as Ängiosperms. In the Wealden flora of England no vestige 

 of an Angiosperni has been found ; this statement holds good 

 also as regards Wealden floras in most other regions of the 

 World. On the other band, as soon as we ascend to strata of 

 sHghtly more recent age we are confronted with a new dement 

 in the Vegetation, which with amazing rapidity assumes the 

 leading röle. It is impossible to say with confidence at what 

 precise period of geological history the Ängiosperms appeared. 



From plant-bearing rocks of Portugal, regarded as homo- 

 taxial with those which British geologists speak of as Wealden, 

 the late Marquis of Saporta named a fragment of a \q.q\ Alis- 

 macites primaeviis, a determination that, while possibly correct, 

 cannot be accepted as conclusive testimony. In Virginia and 

 Maryland there occurs a thick series of strata known as the 

 Potomac formation from which a rieh harvest of plant-remains 

 has been obtained. Prof. Lester Ward has recently shown 

 that ander this title are included several floras, some of which 

 are undoubtedly homotaxial with the Wealden of Europe, 

 while others represent the Vegetation of a later phase of the 

 Cretaceoiis era. From the older Potomac beds a few leaves 



