THE EOCENE OF EUROPE AND NORTH AMERICA 151 



The Collective Fauna of the Phosphorites of Quercy 



The beginning of these fissure deposits occurred during Bartonian times; 

 they richly display the life of the Upper Eocene or Ludian stage, and extend 

 into the totally different mammalian fauna of Middle Oligocene or Stampian 

 times, thus representing a very long period of time. They are the most 

 extensive and famous mammal-bearing fissure deposits which have ever 

 been discovered. They are found in Jurassic calcareous fissures, 3 to 6 

 meters in width and 35 meters in length ; the matrix is a phosphate of lime, 

 probably of mineral spring origin. The mammalian fauna is of extraordi- 

 nary richness, beauty, and completeness. Gaillard ^ considers that the 

 phosphorites were formed as a result of alternation of wet and dry seasons, 

 such as we see in the tropics to-day; tricklings of rain water filled crevasses 

 in the rocks and became saturated with the dissolving limestone; this 

 process was followed by the advent of the dry season, a period of evapora- 

 tion, during which the phosphorites were precipitated. The mammals often 

 occur entire, as in caverns to-day. Filhol,' in his monograph, suggested 

 that death was caused by asphyxiation due to poisonous vapors rising from 

 the hot springs. 



The birds of Quercy. — The recent studies by Gaillard ' on the bird life 

 preserved in these fissures throws a very important side light both on the 

 climatic condition of the period and the zoogeographic relations of France 

 at this time, that is, between the Middle Eocene and Middle Oligocene. 

 The birds, like the mammals, of the phosphorites show so little resemblance 

 to those of the present day that very few can be referred to living genera. 

 They are all types fitted to inhabit great warm plains, scattered with groves. 

 They can be referred to the following groups: diurnal and nocturnal birds 

 of prey (Raptores) ; the American vultures (Cathartidae) ; the serpenteaters 

 (Serpentariidse), of which the existing African 'secretary bird' is the only 

 existing form; the storks (Ciconiidae) ; the sandpipers (Totaninae); the 

 rails (Rallidse); the Old- World quails (Perdicinae) ; the Asiatic and African 

 sand grouse (Fteroclidae) ; and the rollers (Coraciidae), cuckoos (Cucuhdae), 

 goat-suckers (Caprimulgidae), and swifts (Cypselidae) of the large group 

 Pico-passeriformes. Entirely lacking are several families of aquatic birds 

 and proloably the true sparrows. It is an essentially tropical assemblage. 

 The descendants of the Quercy birds, or at least such forms as approach them 

 most closely, are now for the most part inhabitants of the equatorial regions 

 of Africa and South America. Thus the serpenteaters, the gangas, or sand 

 grouse, the gallinaceous birds of the genus Palceocryptonyx, the rollers 

 (Geranopterus) , and the touracos (Dynamopterus) lend to the Quercy fauna 

 an African or Indo-Malayan aspect. On the other hand, there are forms 



• Gaillard, C, Les Oiseaux dcs Phosphorites du Quercy. Ann. Univ. Lyon, n.s., I, Sci. 

 Med., no. 23, 1908. 



^ Filhol, H., Recherchcs sur los Phosphorites du Quercy, Paris 1877, p. 127. 



