2. Helvétien, Middle Miocene

Fortunately for the mammalian palæontologist a large fresh water basin (termed 'Lac de l'Armagnac' by Canu) was formed in southwestern France. Here were deposited the Calcaires de l'Armagnac (300 metres); in the lower levels are the famous Calcaires de Sansan, discovered in 1834; these were placed in the Langhien by LAPPARENT ('85, p. 1198) but are considered at the base of the Helvétien by Depéret; the rich Sansan fauna, containing both large and small animals and many skeletons, was first made known by LARTET ('51), and more recently has been monographed by FILHOL ('91).

Upon a higher level than Sansan, separated by conglomerates (LAPPARENT, '85, p. 1189), are the Calcaires de Simorre (originally compared with the Calcaire de Montabuzard by Douvillé) FILHOL ('91, p. 9) treated the Sansan and Simorre fossils as of the same age; he did not for example separate Rhinoceros simorrensis from R. sansaniensis; the writer finds that the former is specifically different from the latter and is of slightly more recent type. Simorre is thus geologically on a higher level and faunally somewhat younger than Sansan although still within the stage Helvétien, as arranged by Depéret. Parallel with Simorre is Saint Gaudens (Haute Garonne), according to Gaudry and Depéret. At the extreme base of the Helvétien and therefore parallel with Sansan or the 2d Mediterranean (Suess, DEPÉRET, '92, p. 156), are the Lignites de Styrie or the Steiermark Braunkohle (Eibiswald, Wies, Göriach, Voitsberg); the fauna of these outlying lignites of the Mediterranean sea invasion has been fully described by Suess, Peters, Hoernes, Hoffman, Toula. Leiding, in Southern Austria, is said to be of the

same age.

The lignites of Monte Bamboli (Tuscany) are placed by LEPSIUS in the Langhien; their position is doubtful; they are here placed in the Tortonien.

3. Tortonien, Upper Miocene

This is the middle miocene' of Gaudry, Depéret, Gaillard and others who include Pikermi in the Upper Miocene; it is the upper miocene of those who place Pikermi in the Plio

cene.

Grive-Saint-Alban (Isère), explored by JOURDAN between 1845 and 1861, should now be regarded as typical upper miocene. That the mammalian fauna of this stage is distinctly more recent than that of Sansan and Simorre was maintained by DEPÉRET ('87, p. 22; '92, p. clvi) who showed that of 34 species 14 occur in Sansan; GAILLARD ('99, p. 75) has increased the faunal list of LaGrive to 63 species and the new types he records all tend to emphasize the more recent age of this remarkably rich and typical fauna; many of the forms, however, such as Felis, Ursus, Sus, recorded by Gaillard are Pliocene genera, which probably should receive different names.

The best known parallel of La Grive are the sands of Steinheim, Württemberg, in which upwards of 30 species have been recorded (fauna, see LEPSIUS, '92, p. 586); twenty of these species are common with those of La Grive. In Bavaria are the deposits of Günzburg, Ries (Nordlingen) and Georgensgemünd, In Switzerland are the Eningen beds (Obere süsswassermolasse, Molasse d'eau douce supérieure), famous not only for its fauna. but for its remarkable flora. This flora, as monographed by Heer, indicates a climate similar to that of Madeira and Japan; other localities of the upper molasse are Elgg and Käpfnach. In the Paris basin is the Molasse de l'Anjou (DEPÉRET, '92, p. 155); the St. Jean de Bournay; in the Rhone basin the Cucuron (Molasse) and Cabrières (Marnes).

Op. cit., "Les nouveaux mammifères rencontrés à la Grive tendent à donner à la faune de ce gisement une physionomie toute particulière et à la rapprocher davantage de la faune actuelle."

VI. PLIOCENE OF EUROPE

The mammalian faunal base of the Pliocene is defined in its northern facies by the Eppelsheim beds, in its southern facies by the very rich Pikermi deposits-the differences being entirely explainable by climate and latitude. Lepsius, the chief authority upon the geology of the Mayence Basin, holds (in opposition to Schlosser) to the unmixed character of the Eppelsheim fauna and to their unquestionable Pliocene age. The early identifications of Eppelsheim rhinoceroses, etc., with those of Sansan by Kaup and others were erroneous; according to the writer's recent observations they are very distinct. In both the German and Greek beds as maintained also by Eymar, Blanford, Lapparent and Schlosser the Pliocene age is unquestionable.

A new type of horse Hipparion, with very complex teeth and apparently a new comer to Europe, is common to both horizons, so are certain rhinoceroses and Ancylopoda but among the ruminants the hardy deer of Eppelsheim are replaced by antelopes and giraffes in Pikermi. Thus fortunately the beginning of the Pliocene is as sharply determinable by its mammalian fauna as the beginning of the Miocene.

In time and geographical history the Pliocene period extends between the completion of the Alps and the establishment of the main coast lines of modern Europe, the last touches to these lines being given in the Pleistocene and establishing their modern aspect. Marked throughout by continuous volcanic disturbances. the period included a prolonged land depression in southern Europe and extensive invasions of the sea as shown in the following table:

2. PLAISANCIEN.

I. MESSINIEN.

Maximum marine subapennine invasion, long arms of the sea up the Po and Rhone valleys. Mediterranean extends to the East. (Argiles bleues subapennines). Chiefly marine deI posits.

Renewed advance of the sea, brackish and freshwater conditions. Mediterranean bounded by Sardinia on the east; great Caspian seas and lakes beyond.

Mammalian fauna unknown, except that of Casino at the base of this stage.

Fauna of Pikermi and Eppelsheim.

Climate.—Owing to the warm Mediterranean invasion the climate was mild. DEPÉRET, our chief authority ('93, p. 529), shows that there was no decided change of flora; nevertheless the period was marked by the very gradual advance of northern forest types and by the recession of the more delicate southern types, the palms for example being driven 10 degrees further south. The decisive lowering of temperature came during the early Pleistocene period.

1. Messinien, Lower Pliocene

During the first or Messinien stage the fauna of the lakebound Ægean region (Pikermi), altogether similar to that of Southern France (Mt. Léberon), indicates abundant if not highly watered vegetation and extensive grazing pasturages of central African type. This fauna was widely distributed and highly distinctive; the parallels are numerous and well known.

Orient.

France.

Austro

Hungary.

Spain.

Germany.

Pikermi-typical southern fauna.

Samos (Egean Sea), Maragha (Persia).

Mt. Leberon (Vaucluse).

Molasse d'eau douce supérieure du Rhône (higher than beds of same name in Switzerland).

Cucuron (Couches saumâtres). Puy Courny (Cantal).

Belvédère Schotter, fluviatile gravels (Pontique, Depéret, '92. p. 156, Congeria Beds, Vienna Basin).

Concud (Ebre Valley, near Madrid, a very extensive lacustrine formation), 'Alcoi.

Eppelsheim gravels (4-7 metres), near Darmstadt.

Upper Dinotherium sands, of Augsburg, Neuburg, Delsberg.

Distinctive types of this stage are Pliohylobates (Eppelsheim), Hystrix (Pikermi), Pliohyrax (Samos) Hipparion gracile. Acera

therium incisivum of Eppelsheim succeeds the A. tetradactylum of Sansan; the above are dolichocephalic rhinoceroses, possibly ancestral to Elasmotherium; R. schleiermacheri possibly is a very large successor of R. sansaniensis; R. goldfussi (Eppelsheim), a successor of R. brachypus of la Grive-Saint-Alban; R. blanfordi (Maragha) also represents the short skulled or brachycephalic race; R. pachygnathus is probably an African immigrant. Dinotherium giganteum replaces D. bavaricum. So throughout the Mammalia, besides numerous newly introduced forms, such as Pliohyrax and Orycteropus, there is a marked evolution beyond the upper Miocene types.

2. Plaisancien, Lower Pliocene

As this is chiefly a marine phase the terrestrial mammalian fauna is unknown except in the lignites of Casino (Tuscany) at its base; these are equivalent to the Couches saumâtres à congéries, according to Depéret, and Lapparent. Here are found Hipparion gracile, Sus erymanthius, Antilope massoni, Tapirus priscus, Semnopithecus monspessulanus and other lower Pliocene types. This is the 'pliocène inférieure' of Gaudry, Depéret and others who have maintained the upper Miocene age of Pikermi. Upon a somewhat higher level than Casino are the following marine formations of England in which many cetacean and a few terrestrial types occur; the parallels are:

Coralline Crag (Suffolk), marine, containing Mastodon, Rhinoceros. Red Crag, inferior or Nodule Beds, Marine, containing a fauna equivalent to that of the Astien stage in part.

3. Astien, Middle Pliocene

This stage contains the faune pliocène ancienne' of Depéret, or the older pleiocene fauna' of certain English authors who have not recognized Pikermi as the typical older Pliocene. Typical localities are the following:

Rousillon.

Sables sillicieux gris (25 metres), fluvio-lacustrine, fauna very similar to that of Montpelier.

Montpelier infer. Sables jaunes marins (50 metres), described by Gaudry and representing the Plaisancien faunal stage in part.