102 



THE AGE OF MAMMALS 



/. BASAL EOCENE, FIRST FAUNAE PHASE — MAMMALS SOLELY 

 OF THE ARCHAIC TYPE COMMON TO THE NEW AND OLD 

 WORLDS 



Animals of the First Faunal Zone. — The Basal Eocene life zones in 

 both countries are sharply characterized by the extinction or absence of 

 the giant reptiles, by the survival from the Cretaceous of the large swamp 



Fig. 26. — Basal and Lower Eocene. Thanetian, Cernaysian, Lower Landenian. 

 FRANCE. — Glauconio de 1 la Fere (Aisne), fluvio-marine deposits (6 meters). Gravier 

 marin de 2 Cernfly, near Reims (.5-7 meters). Sables et calcaires de 3 Rillij, near Reims, 

 lacustrine. Sables de 4 Chdlons-sur-Marne (Marne). Sparnacian, Upper Landenian. 

 BELGIUM. — 5 Erque.linnes, near French boundary. FRANCE. — Argile plastique et 

 lignites de 6 Soissons (Aisne), 7 Guny, 8 Muirancourt, near Paris. 9 Saron, near Ste. Maxence. 

 10 Laon (Aisne). 11 Upper Cernay, near Reims. Conglomerat de 12 Meudon, near Paris. 

 Lignites de 13 Vaugirard, near Paris. Travertin de 14 Sezanne (Marne), a calcareous tuff 

 rich in plants. ENGLAND. — Woolwich and Reading Beds, " plastic clay," of 15 Duhcich, 

 16 Croyden, near London, marine and cstuarine (4-28 meters) sands and clays. Lower 

 Ypresian. ENGLAND. — 17 London clay of 18 Heme Bay (Kent), 19 Kyson, north of Har- 

 wich, 20 Harwich (Essex), 21 Isle of Sheppey, mouth of the Thames, marine and estuarine 

 deposit (over 500 feet maximum). FRANCE. —^ Marine deposits of 22 Pourcy, near Reims. 

 Upper Ypresian. FRANCE. — In Marne, near Epernay : 22 Chavot, sables a teredines d'Ay, 

 marine (3-4 meters) , marnes de Cuis. Correlation of Deperet. 



or fiuviatile lizard Champsosaurus (of the order Choristodera or long- 

 snouted Rhynchocephalia). In the Rocky Mountain region this animal 

 is also found in the underlying Laramie formation. Its survival both 

 in the Rocky Mountain region, in Belgium, and in France is one of the 

 most distinctive features of the Basal Eocene, because it is apparently on 

 the verge of extinction and does not reappear in higher levels. 



