If we take up any work treating of fossil plants we shall generally find the difficulties of the subject emphasized and the disadvantages recounted under which the palæobotanist is placed as compared with the palæozoologist. The latter finds rich material preserved in media, and under conditions, in which fossil plants never occur. Animals too, from the nature of their organisation, are far better adapted for preservation in a fossil state than the more delicate and perishable structures of plants. In questions of geological chronology and correlation animals have generally been preferred to plants, both on account of their greater abundance in the stratified rocks, and because they have been considered safer guides. Bunbury, writing on the vexed question of Indian stratigraphy, remarked—“The palæobotanical evidence is far from unequivocal, and, such as it is, might be outweighed by the discovery of a single, well marked and thoroughly characteristic, fossil shell or coral.” This shews what little importance is attached, by some at any rate, to the correlative value of fossil plants.

Palæobotanists have for the most part expressed their confidence in plant evidence. We are not concerned, at present, with the defence of Palæobotany as a valuable aid to Palasozoology in stratigraphical geology, nor with supporting the opinion of some of the more sanguine that plants may indeed be more reliable tests of age than fossil animals.