Ix. PRESIDENT'S ADDRESS. 



There were considerable changes in the geographical conditions 

 of our globe towards the close of the Palaeozoic Age, when the 

 Carboniferous beds were thrown into abrupt folds. Such was 

 the case with the coal-fields of Belgium, of Pas de Calais, and 

 of Somersetshire. The Fauna and Flora of the Permians had died 

 out, and were replaced by new types during the deposition of 

 the Trias beds, which are the earliest of the Mesozoic Period. 

 Both the Trias and the Permian beds were laid down under 

 conditions of marked physical disturbances. Great Reptilians, 

 the precursors of the Mammalia, appeared at the close of the 

 Permian Age and the earlier portion of the Trias. The old 

 floras were replaced by others scarcely more advanced in 

 structure. These mainly consisted of Conifers, Cycads, Ferns, 

 and gigantic Equisetacea. Comparatively few Palaeozoic Cycads 

 are known. They were world-wide in the Mesozoic age, and 

 grew as far north as Greenland; now they are limited to the 

 warmer temperate regions. They were tolerably numerous in 

 the Greensand; after that period the group diminished greatly 

 in importance, but survived in the south of Europe during the 

 Tertiary. Cycads are Exogens, and from the shortness of their 

 stems it is probable they contributed to the undergrowth of 

 the ancient forests. The date of their first appearance is not 

 absolutely free from doubt. They have been referred to the Coal 

 measures ; the Rhaetic beds of Schonen contain them without 

 any doubt. Trunks of Conifers (Araucaria, &c.) are found 

 frequently in the Purbeck beds of Dorsetshire associated with 

 Cycads ; the Greensand supplies Pinea (Stone-pine). The 

 Abietina are the most abundant of the Conifers in the Tertiary 

 and Cretaceous beds. As a rule they can only be determined 

 by their cones, the Pines by their needle-bearing branches. A 

 few cones have been found in the lowest Cretaceous beds of 

 Hainault in Belgium ; their winged^seeds recall to mind the 

 recent Strolus and Cemlra. 



^ The present distribution of Pinus, north of the tropic of 

 Cancer, extends over both hemispheres in one wide zone from 

 the Philippines to the west and north-west coasts of America 



