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Meximieux (Ain) tufas, famous for its characteristic Pleistocene flora: Bamboo, Sassafras, Magnolia, Laurel.

Sables de Trévoux (Saône)

DEPÉRET'S fine memoir upon Rousillon ('90, p. 538, 539) tends to make this locality typical. Characteristic species not found in Pikermi are R. leptorhinus, Mastodon arvernensis, Tapirus arvernensis, Ursus arvernensis.

Types with Messinien or Pikermi affinities are Hipparion, Palæoryx, Hyenarctos, Dolichopithecus. The Asiatic apes are Dolichopithecus and Semnopithecus. The African antelopes are Palæoryx cordieri and P. boodon.

4. Sicilien, Upper Pliocene

This embraces the newer pleiocene fauna' of English authors, the 'faune pleiocène récente' of Depéret. Hipparion disappears, being replaced by Equus stenonis; Rhinocerus etruscus succeeds R. leptorhinus. Macacus florentinus appears, related to the living Gibraltar form. The Proboscidia are represented by the last of the European mastodons, Mastodon arvernensis and M. borsoni; Elephas meridionalis, the great southern elephant and precursor of the mammoth, is found in Italy and the Saône Valley. This species is absent locally (Depéret) in the Sables à Mastodontes of Puy, Coupet, Vialette. The typical locality is in the classic valley of the Arno in Italy, the so-called l'al d'Arno supérieure; its richness contrasts with the general poverty of Italy in middle and lower Pliocene types.

Italy.

France.

Olivola, a little higher than Val. d'Arno. Summit of Pliocene.

Val d'Arno supér. Thick fluvio-lacustrine beds (60 metres). Fauna fully listed by Stefani.

Astésan, Villafranca (San Paola), Tossano.

Sainzelles (Puy) a little higher than Perrier.
Perrier (Issoire) fluviatile gravels.

Montpellier super. (Rhône), fluvio-lacustrine.

Coupet super., volcanic deposits.

Vialette (Haute Loire, near Puy).

Chagny (Saône) fluviatile clays and sands.

Sables à Mastodontes du Puy.

England. Red Crag (Suffolk) Marine.

Norwich Crag (Norfolk) Fluvio-marine.

ANNALS N. Y. ACAD. SCI., XIII, July 19, 1900—3

This arrangement is mainly upon the authority of Depéret.

It is important to note that Boule, another eminent French authority, differs in the arrangement of the Pliocene in particulars which will be discussed later.

To the north, in the Red and Norwich Crags of England, are said to appear the earliest arctic types of shells, the prophets of the glacial period. Also here (Norwich Crag) occurs the earliest giant beaver Trogontherium minus. The roe and stag deer become varied in southern France.

VII. PLEISTOCENE

In the Pleistocene period the fullness of European investigation is in strongest contrast with the indecisive results of American work and in no other period can we anticipate more weighty inductions from Holarctic correlation. The period is distinguished as the Ice Age and by the first recorded traces of man in beds which have been claimed as Tertiary but are properly Quarternary.

The Pleistocene history of Europe is still in a formative stage but it is absolutely evident that a final and positive time scale and subdivision of the early Age of Man is not far distant and that the vast labors of European geologists, botanists, zoölogists, palæontologists and anthropologists will be rewarded with a harmonious theory of all the phenomena of the Pleistocene.

Combined attack by geological and biological methods has nowhere produced more brilliant results. The unaided testimony of the rocks and soils fails to tell us of the successive advances and retreats of the ice but where, owing to the obliteration of surface deposits, geology is in confusion, plant and animal life serves both biology and meteorology like a vast thermometer actually recording within a few degrees the repeated rise and fall of temperature. This record consists of the invading and retreating life waves of river, forest, field, barren ground, steppe, tundre and arctic types with increasing cold, or the reversed order with diminishing cold, in the same localities or geographical areas. There seems to be sufficient evidence for a subdivision of the Pleistocene as shown in the Table below.

UPPER PLEISTOCENE: Post Glacial.

MIDDLE PLEISTOCENE: Glacial.

LOWER PLEISTOCENE: Preglacial.

Briefly, the glacial story presented in the second column of our Table is as follows: (1) The preglacial stage presents a mingling of south temperate, temperate and northern forms. (2) The long first glacial advance was followed (POHLIG) by the Rixdorf stage, intermorainal, colder than the succeeding Mosbach and Thuringian stages which have a more temperate facies in the recurrence of some of the Forest Bed fauna. (3) The faunal evidence for a colder mid-glacial period is conclusive; the evidence for a second or mid-glacial advance, between the first and last great glacial stages, is mainly biological, that is subarctic are followed by more temperate life forms, as we gather largely from studies of the rodent fauna by NEHRING, STUDER and others. The hypothesis of three distinct glacial advances and of two interglacial retreats rests therefore upon a combination of geological and biological evidence which is not as yet. conclusive. We shall consider it more fully after discussing the fauna. It is supported geologically by observations of Penck and Böhm in the Bavarian Alps. Upon this theory the Pleistocene history with its fluctuations of temperature is epitomized in the following Table. This Table is an attempt to combine the chief results of the masterly work of DAWKINS, POHLIG, Boule, NEHRING, STUDER, WOLDRICH, SCHLOSSER, and others. None of these authors has treated the whole period; yet there is an evident harmony and synthetic trend in their work.

Deposits. Geologically we have to do with the characteristic glacial deposits, boulders, boulder clay or drift, gravels and till. The origin of the fine calcareous loam termed "Loess" distinguishing the upper middle Pleistocene is still under debate; it is partly glacial mud; partly subærial, it is also subsequent to the second glacial stage, and in part postglacial. We find also the river deposits of the lower and mid-Pleistocene (Forest Bed, and Mosbach) as well as of all higher divisions. The mid-Pleistocene was distinguished by volcanic disturbance, as attested in Thuringia by the volcanic travertines and tufas.

There are also

PARTLY THEORETICAL DIVISIONS OF EUROPEAN PLEISTOCENE, AFTER

POHLIG, DEPÉRET, NEHRING AND OTHERS

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lake and sea-beach deposits constituting the lacustrine and ma-
rine terraces. The very characteristic cave deposits, breccias
and earths belong to the upper mid-Pleistocene. Then there are

the younger river alluvia, lake bottoms, aëolian sands, peats and

mosses.

Geographic Changes.-The beginning of the Pleistocene is remarkable for its broad land connections and it represents the last stage of that community of fauna which during the Pliocene distinguished the entire region of Europe, Asia and Africa. The mid-Pleistocene period in Europe is mainly one of continental depression; (1) at the climax of the first glacial advance extensive portions of northern Europe were submerged beneath the sea; (2) at the close of the first interglacial or temperate period (Elephas antiquus stage) occurred the volcanic disturbances in Central Europe and the hot spring formations of Thuringia (Taubach, Weimar); at this time all the old continental connections characteristic of the Tertiary and serving as land bridges for free Holarctic, Oriental and Ethiopian migration began to break up in the following manner: during the early mid-Pleistocene or Elephas antiquus stage (POHLIG) the English Channel broke through the long preëxisting land-bridge between England and France; Great Britain was faunally isolated; similarly the Irish Channel was depressed and Ireland lost its land connection with Wales in the early Pleistocene and with Scotland in the newer Pleistocene.1 In the Mediterranean region, also, at the close of the first interglacial period (Pohlig) the land bridge across Gibraltar, also that between Italy, Sicily and Africa was broken; Malta 2 was isolated as an Island and the great Elephas antiquus dwindled into the small insular type E. melitensis. To the eastward the Mediterranean extended into the Egean plateau, which had previously been terra firma, and the Ægean sea cut off the land connection between Greece and Asia Minor. It is important to note as observed by Wallace and Lydekker, that the arid and desert land connection still existing between Europe and Africa at the Isthmus of Suez constitutes practically a faunal barrier as impassable for most mam

1 According to Scharff, Ireland has yielded only ten Pleistocene species, including the Northern Lepus variabilis and Reindeer and the great Megaceros hiberniæ, which is found in the post-glacial peat moors.

2 Malta shows evidences of two periods of elevation and depression. See POHLIG, also Leith Adams, "The Nile Valley and Malta," London, 1870.

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