It is interesting to find that when we ascend higher in the geological series and pass beyond the Wealden strata to the Middle and Upper sub-divisions of the Cretaceous period, evidence of the wide geographical distribution of the Araucarieae is still abundant. Araucarian wood has been obtained in rocks classed as Upper Cretaceous in Egypt, in East Africa, in Dakota, and elsewhere. In the sedimentary rocks of the Tertiary period undoubted examples of Araucaria are less common, though there can be no doubt that the genus was much more widely spread then than it is at the present day. The well-known Tertiary plant-beds of Bournemouth have afforded specimens of foliage shoots which have been described as a species of Araucaria, though in the absence of well-preserved cones or petrified wood we must admit that the data are inconclusive. It is, however, legitimate to regard the striking similarity of the Bournemouth twigs to those of Araucaria excelsa and A. Cookii as constituting a fairly strong case in favour of the persistence of Araucaria in Western Europe up to the earlier stage of the Tertiary period. Araucarian wood of Tertiary age is recorded from India, while branches with broad leaves like those of Araucaria imbricata have been found in Seymour Island and the Magellan Straits, and specimens of Tertiary wood are described from Patagonia. At the other end of the world. Tertiary rocks on the west coast of Greenland have yielded fragments which may be referred with some hesitation to the genus Araucaria.
A few words must be added in regard to the recent discovery by Professor Jeffrey and Dr Hollick of some very interesting Cretaceous specimens in New Jersey of well-preserved cone-scales and foliage shoots of extinct plants closely related to the existing species of Agathis([51]). The American fossils are particularly valuable because their preservation admits of microscopical examination of the tissues. In Cretaceous rocks of Staten Island and in other localities on the eastern border of the northern United States, kite-shaped seed-bearing scales almost identical in form with those of recent species of Agathis are fairly common fossils. Similar specimens have long been known from Tertiary rocks in western Greenland. In the case of some of the American examples each scale bore three seeds instead of a single seed in living species: on account of this difference Prof. Jeffrey and Dr Hollick have adopted a distinct generic name, Protodammara.
The foregoing sketch is necessarily far from complete, but it may serve as an illustration of the light which is thrown on the past history of recent plants by the investigation of the relics of ancient floras. The family Araucarieae now represented by a small number of species which, with the exception of the Andian and Brazilian Araucarias, are restricted to a small region in the southern hemisphere, was one of the most widely spread sections of the seed-bearing plants during the Mesozoic era. Ancestors of Araucaria must have been common trees in the European vegetation in Jurassic and Lower Cretaceous periods, and even as late as the Tertiary period there is evidence that representatives of the family still lingered in the north. One conclusion which seems almost unavoidable is that the species of Araucaria and Agathis that survive, in some cases only in one or two small islands in the South Pacific, have in the course of successive ages wandered from the other end of the world. Their migrations can be partially traced by the fragments embedded in Jurassic and later sediments, but we can only speculate as to the causes which have contributed to the changes in the fortunes of the family; how much influence may have been exerted by changes in physical conditions in the environment, and to what extent the production of more successful types may have been the dominant cause of the decline, it is impossible to say. One thing at least is certain, that few existing plants are better entitled to veneration as survivals from the past than are the living species of Araucaria.
[CHAPTER VIII]
THE MAIDEN HAIR TREE
'...the trees
That whisper round a temple become soon
Dear as the temple's self.'
Keats.