It is of course very necessary to learn the names of plants, and be able to describe them according to a system; but no one should be satisfied without employing the microscope to elucidate minute structures, and acquiring at least the rudiments of vegetable physiology and morphology.

EXPLANATION OF PLATE XCVI.

FIG. 1. Deutzia Scabra, stellate leaves on flower-bud. (Mag.) 2. Gum Cistus, sepal hairs. (Mag.)

3. Coleus leaf, hairs and glands. (Mag.)

4. Hypericum pulchrum leaf, with marginal glands. (Mag.)
5. Azalea anthers. (Mag.)

6. Rhododendron anthers. (Mag.)

7. Berberis Darwinii anthers, with lids. (Mag.)

8. Narrow-leaf Bay anthers, with lids.

filaments and anthers. (Mag.)

10. Canna anther and stigma, with petal-like expansions. (N. S.) 10 A. Portion of stigma in section. (x 200).

11. Fuchsia anther, with petal-like expansion. (N. S.)

THE PHYSICAL GEOGRAPHY OF THE MEDITERRANEAN DURING THE PLEISTOCENE AGE.

By W. BOYD DAWKINS, M.A., F.R.S.

[PLATE XCVII.]

IN

*

a preceding essay we have seen that north-western Europe was elevated, during the Pleistocene Age, to an extent of at least 600 ft. above its present level, so that Ireland was united to Britain, and Britain was joined to the mainland of Europe, proof of this elevation being dependent upon the soundings on one hand and the distribution of the fossil mammalia on the other. Such a change must necessarily have affected the whole physical conditions of the area, since the substitution of a mass of land for a stretch of sea and the higher altitude of the land would tend to produce climatal extremes of considerable severity. It is indeed no wonder that, during this time of continental elevation, the hills of Wales, Yorkshire, Derbyshire, Cumbria, and Scotland should have been crowned with glaciers, or that there should have been a migration to and fro of animals, comparable to that which is now going on in Siberia and the northern portions of North America. I propose in the present essay to apply the same modes of investigation to the Mediterranean area. The condition of southern Europe at that time has a most important bearing on any conclusion which may be drawn as to the Pleistocene climate in France, Germany, or Britain. For if it be proved that a mass of land then extended where the Mediterranean sea now rolls, the extension would increase both the heat of the summer and the cold of the winter in central and north-western Europe.

The geological evidence that the Mediterranean region has

"On the Pleistocene Climate and the Relation of the Pleistocene Mammalia to the Glacial Period."-P. S. Review, Oct. 1871.

been subjected to oscillations of level during the Tertiary period, is clear and decisive. Professor Gaudry has proved, in his work on the fossil remains found at Pikermi, that the plains of Marathon, now so restricted, must have extended, in the Meiocene Age, far south into the Mediterranean, to have supported the enormous troops of hipparions and herds of antelopes, the mastodons, and large edentata, revealed by his enterprise. The rocky area of Attica, as now constituted, could not have afforded sustenance for such a large and varied · group of animals, nor would the broken hills and limestone plateaux have been inhabited by hipparions and antelopes, if their habits at all resembled those of their descendants living at the present time. It may, therefore, reasonably be concluded that Greece, in those times, was prolonged southwards, and united to the islands of the Archipelago by a stretch of land; and if Africa were then, as now, the head-quarters of the antelopes, it is very probable that one of the lines by which they passed over into Europe, and spread over France and Germany, was in this direction. Nevertheless, it must be admitted, that the changes of level, which have taken place since the Meiocene Age in those regions, are so complicated as to render it almost impossible to restore the Meiocene geography.

In the succeeding, or the Pleiocene Age, the presence of the African hippopotamus in Italy, France, and Germany, can only be accounted for by a more direct connection with the African mainland than is offered by a route through Asia Minor. It would seem, therefore, that then the Mediterranean Sea could not have formed the same barrier to the northern migration of the animal which it does now. In many regions, however, the present land has sunk beneath the sea; and marine strata, of Pleiocene Age, are accumulated in the Val d'Arno, Sicily, and southern France.

In treating of the physical conditions of the Mediterranean area in the Pleistocene age, I shall first of all take the evidence of the mammalia, and then compare it with that offered by the varying depth of the sea at the present time, following out an idea suggested by the late Dr. Falconer in a speech before the British Association in 1863. The mammalia of the Iberian peninsula will be taken first.

The researches of Captain Broome, Professor Busk, and of Dr. Falconer,* in the bone caves of Gibraltar, carried on through a long series of years, have established the fact, that African animals lived in considerable numbers on and around that

"Falconer Palæont.Mem. " vol. ii. Busk, "International Congress." "Prehistoric Archæol." Norwich.