774 Excursions of the Geological Soc. France, 1878. [December 
at Gournay at the close of the day was an enjoyable event, and 
was enlivened with toasts and speeches.’ 
The excursion of the 11th of September was again in the 
immediate neighborhood of Paris, and had for its object the 
examination of the famous series of the Gypsum. Passing by 
rail to one of the suburban stations, the party followed on foot 
the course of the Seine to the village of La Frette. Here a 
steep bank, having at a distance much the appearance of a ter- 
race, forms the lower part of the boundary of the river valley, 
passing behind the village of Sarcouville and extending along 
the foot of the ridge which here separates the valley of the Seine 
from a valley immediately to the east of it. The escarpment of 
this ledge does not exceed twenty feet in height, but it displays a 
beautiful section of that part of the middle Eocene known as the 
Sables de Beauchamp. As it offers a good illustration of the 
manner in which the Tertiaries of the region of Paris are subdi- 
vided into thin beds, which represent frequent changes in the 
character of the water and of ‘the sediment, I give them as 
explained on the spot by Dr. Vélain. The lowest bed is a marine 
sandstone which becomes brackish in its superior part, and con- 
tains Ostrea cucullaris. Reposing on it is a limestone of lacus- 
trine origin, containing Lymne@a arenularia; in a part of the 
escarpment this bed is wanting. It is succeeded above by a thin 
bed of scarcely adherent sand, containing Melania hordacea, and 
believed to have been deposited in brackish water. Above this 
is a stratum of compact marine limestone containing Cytherea ele- 
gans and Potamides. A lacustrine limestone called the Calcaire de 
Ducy rests on the marine limestone. This bed repeats the second 
bed 6f the series in the possession of the Lymn@a arenularia, the — 
specimens presenting a slight varietal difference. It is this forma- 
tion which contains the oldest remains of Pa/@otherium, as 1 was 
informed. In the locality described, the soil of the ascending 
face of the hill conceals higher beds from view, so that it became 
necessary to pass to other localities in order to study them. 
The party accordingly ascended to the crest of the water shed, 
passing through orchards and vineyards on its slope. The apples 
were abundant, but not of good quality. On the summit stood 
a ruined windmill, forming a landmark, and near it a restaurant 
~ and café commanding a beautiful view of the rich and populous 
valley on its north-east side, and of the hills beyond. From this — 
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