GYMNOSPERMtE. 



13 



temperature. Cones are of necessity associated with the fruits in most of the forms 

 known definitely to belong to the Taxodieas. 



Of the Taxeae, Ginkgo or Salisburia occurs in Ettingshausen's list of Sheppey plants ; 

 but it is just possible that the resemblance in the form of the seeds is accidental, for they 

 appear to have a hilum, and are of much smaller size. Eorms of Ginkgo are associated 

 with nearly all the northern floras, from the Jurassic age onward, but seem absent in 

 temperate Europe between the Jurassic and later Miocenes. The Podocarpese, again, are 

 much more numerous than they appear in Ettingshausen's lists. At Bournemouth there 

 are at least two types, one of which, with long articulated leaflets, extends north to Mull 

 and Antrim, and is common in the Middle Eocene of Europe. There are Podocarp 

 berries at Sheppey ; and all the remains of Conifers from Alum Bay are now placed in a 

 single species of Podocarp with dimorphic foliage. 



Of the Araucarieae, Araucaria is certainly represented in our Eocene, and is confined 

 to the upper part of the Bournemouth series. The former connection of this with the 

 Australian region, indicated by this Conifer, is strengthened by Callitris and Podocarpus ; 

 while the remainder of the Conifers? confirm the close connection with America and 

 ^f'"" Eastern Asia, already rendered apparent by the Eerns. The Abietinese have taught but 



little hitherto ; but cones of Pinus have been found near Canterbury, at Heme Bay, 

 the Isle of Sheppey, Bracklesham, Barton, Gurnet Bay, and Antrim. Ettingshausen 

 believed that bodies resembling scales of cones from Alum Bay, and a pair of indistinct 

 acicular impressions from Bournemouth, indicate the presence of Pinus in these floras. 

 Strong evidence that all the freshwater deposits, whence floras are obtained in England, 

 were deposited in running water is afi'orded by the fact that they are so devoid of remains 

 of Pines ; since it is certain, from their common occurrence in the marine formations, that 

 they formed part of our flora throughout the whole Tertiary Period. 



Sir Joseph Hooker has recently expressed the opinion that " Of all the orders of 

 fossil plants of the formations referred to (the Cretaceous and Tertiary strata of North 

 America), the Gymnosperms alone have, as a rule, yielded much trustworthy information ; 

 and this is due to their texture, to the peculiar character of their vegetative and repro- 

 ductive organs, to the frequent adhesions of these to the branchlets, to their gregarious 

 habits, to their wide distribution, and to their close affinity with existing species." But 

 the study is, on the other hand, rendered difficult by the great similarity existing between 

 the foliage of widely separated genera, and the rarity with which fruits are found associated 

 with it, at least in deposits formed in flowing rivers. The relative persistence of the 

 various fruits to the branchlets, the piecemeal manner in which so many cones are shed, 

 and the greater length of time they float compared to the foliage, are points seldom taken 

 into account. Just as we might infer when pinnae of Ferns are found abundantly without 

 any trace of sori that the fertile fronds were separate, so when cones are never mingled 

 with foliage we might suppose that they were shed either piecemeal, or at a different time 

 of year, or else possessed very different powers of flotation. 



