44 THE OLIGOCENE BEDS 



of Eure, Vexin, Valois, Brie, and has such a great development to 

 the south that it is difficult to appreciate its limits. It is found in 

 the valleys of the AUier and the Loire, the Cantal and even in the 

 basin of the Garonne. 



In the Beauce and neighbouring regions the lacustrine lime- 

 stone is divided into two parts, separated by a sandy clay.* The 

 lower limestone, the " Calcaire du Gatmais " of M. de Roys, is 

 about forty-eight feet in thickness. It is devoid of flinty matter 

 near Etampes, and the most characteristic fossils are Limncea 

 Brongniarti, L. cornea, Helix Ramondi, Planorbis cornu and 

 Potamides Lamarcki. The remains of several mammals have been 

 found at La Ferte-Alais. This bed is well developed at the 

 quarry of St. Marc. It is quarried for building stone, amongst 

 other places, between Beaune-la-Rolande and Montargis. In 

 the Blois district the Limncca limestone is about sixty-five to 

 ninety-seven feet in thickness, and Amphitragulus elegans, 

 Dremotherium Feignouxi, Tapirus Poirrieri, and other mammals 

 are found. f 



13. SANDS OF GATINAIS. 



Above the lower limestone just referred to, comes the " //lo/asse 

 du Ga final's" of M. Douville, which is made up of green loam 

 with siliceous sands and sandy Limestone. The total thickness of 

 this local deposit is about forty-eight feet, and south of Etampes it 

 is found between the Beauce Limestone, properly so-called, and 

 the T^ifZ/.r-limestone of the Orleanais, which latter is usually, though 

 not always, regarded by French geologists as belonging to the 

 Miocene (see p. 1 1 1). 



AN OUTLINE GUIDE TO THE PRINCIPAL 



SECTIONS AND FCSSILIFEROUS 



LOCALITES.t 



A DESCRIPTION of the best centres for studying the Tertiary 

 geology of the Paris Basin will, we think, be useful to English 

 geologists ; and, as we have visited many of the best sections, the 

 following hints are chiefly the result of personal experience. 



Several sections may often be conveniently reached from a 

 single place ;,and we shall, therefore, indicate the various localities 

 which may be visited from each of these centres, with the distance 



* DouvilM, Bull. Sac. Geol. Fr., 36. s^r., t. iv. (1876), p. 92. 

 t Exp. Carte Gcol. Fr. Blois sheet. 



+ Kor a complete list of the fossiliferous exposures in the Paris basin consult Stan. 

 Meunier, Gcol. des E)iv. dc Paris, Paris (1875), pp. 447, ct sqi}. 



