To turn for a moment to some of the most obvious connections between palaeobotany and the wider sciences of botany and geology. The records of fossil species must occupy a prominent position in the data by which we may hope to solve some at least of the problems of plant evolution. From the point of view of distribution, palaeobotany is of considerable value, not only to the student of geographical botany, but to the geologist, who endeavours to map out the positions of ancient continents with the help of palaeontological evidence. The present distribution of plants and animals represents but one chapter in the history of life on the Earth; and to understand or appreciate the facts which it records, we have to look back through such pages as have been deciphered in the earlier chapters of the volume. The distribution of fossil plants lies at the foundation of the principles of the present grouping of floras on the Earth’s surface. Those who have confined their study of distribution to the plant geography of the present age, must supplement their investigations by reference to the work of palaeobotanical writers. If the lists of plant species drawn up by specialists in fossil botany, have been prepared with a due sense of the important conclusions which botanists may draw from them from the standpoint of distribution, they will be readily accepted as sound links in the chain of evidence. Unfortunately, however, if many of the lists of ancient floras were made use of in such investigations, the conclusions arrived at would frequently be of little value on account of the untrustworthy determinations of many of the species. In the case of particular genera the study of the distribution of the former species both in time and space, that is geologically and geographically, points to rational explanations of, or gives added significance to, the facts of present day distribution. That isolated conifer, _Ginkgo biloba_ L. now restricted to Japan and China, was in former times abundant in Europe and in other parts of the world. It is clearly an exceedingly ancient type, isolated not only in geographical distribution but in botanical affinities, which has reached the last stage in its natural life. The Mammoth trees of California (_Sequoia sempervirens_ Endl., and _S. gigantea_ Lindl. and Gord.) afford other examples of a parallel case. The Tulip tree of North America and China and other allied forms are fairly common in the Tertiary plant beds of Europe, but the living representatives are now exclusively North American. Such differences in distribution as are illustrated by these dicotyledonous forest trees in Tertiary times and at the present day, have been clearly explained with the help of the geological record. Forbes, Darwin, Asa Gray[39] and others have been able to explain many apparent anomalies in the distribution of existing plants, and to reconcile the differences between the past and present distribution