72 A. BLTTT. [NO 1. 



(3', 6', 7'), the Osborne, which has the most unmixed fresh-water 

 fauna, corresponds with the two lowest arcs (4', 5')- 



For comparison's sake we will again study in detail the 

 profile from Mery-sur-Oise in the Paris basin and compare it 

 with Stockwell's curve in ascending? order. The beds we will 

 number in the same manner as in the original description, given 

 by Dollfus and Vasseur in Bull. Soc. Geol. de France ser. Ill, 

 vol. VI. Paris. 1878. p. 243 ff. 



Sables de Beauchamp et Mortefontaine etc. (beds 89-111). 

 Arcs 14 and the first half of 15. In these marine (and partly 

 brackish?) beds we have at the bottom a pebble bed, above 

 which come at first 5 sandstones alternating with sand, then a 

 limestone and a calcareous marl with intercalated sand and 

 marl, showing thus 6—7 alternations. 



Above these sands lies the Calcaire de St. Ouen (beds 

 112—142), a fresh-water formation, divided by a marine 

 layer (bed 128) into two subdivisions. The lower, from 

 the top of arc 15 to the top of arc 16, has 4 horizons of 

 hard or siliceous limestones alternating with marls. Then 

 comes the marine bed (128) at the top of 16. (This arc, 

 in the curve of Leverrier, ascends higher than in Stock 

 well's curve). In the upper subdivision we have again 

 hard and siliceous limestones alternating with marls and clays 

 6 times. It thus finishes somewhat to the left of the top of 

 arc 2'. 



Sables de Monceaux (beds 143—145) is a marine sand wit& 

 3 layers of concretions. Arc 2'. 



Marne a Pholadomya (beds 146-154) two marine alter- 

 nations of siliceous limestone with marl. 



Gypse n. 3 (beds 155-158). One alternation of marine 

 marl and gypsum. 



Marne a Lucina bed 159. No alternation. 



The beds 146-159 have, thus, together 3 alternations and 

 correspond to the arc 3'. 



Gypse n. 2 (beds 160-196) marine, at least for a grt»* 

 deal. It should, however be observed, that no fossils are 



