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POPULAR SCIENCE REVIEW. 
The fossil plants and associated seams of lignite, and of 
more or less perfect coal, are intercalated with beds of sand and 
clay of considerable thickness, evidently derived from some 
neighbouring land, and interstratified with them are occasional 
bands of limestone with marine shells. “ On the whole,” says 
Sir C. Lyell, “ the organic remains and the geological position 
of the strata prove distinctly that in the neighbourhood of Aix- 
la-Chapelle a gulf of the ancient Cretaceous sea was bounded 
by land composed of Devonian and carboniferous rocks. These 
rocks consisted of quartzose and schistose beds, the first of 
which supplied white sand, and the other argillaceous mud, to a 
river which entered the sea at this point, carrying down in its 
turbid waters much drift-wood and the leaves of plants. Occa- 
sionally, when the force of the river abated, marine shells of 
the genera Trigonia , Turritella , Pecten , Hamites , &c., estab- 
lished themselves in the same area, and plants allied to Zoster a 
and Fucus grew on the bottom.” * 
But the position of the Aachenian sands in Belgium and the 
north of France, which are at the base of the Cenomanian, has 
been differently assigned, and were the subject of considerable 
discussion at the annual meeting of the Geological Society of 
France at Avesnes (1874).f M. Gosselet refers them to the 
gault. M. de Lapparent, agreeing with the late M. Dumont, 
believes they correspond to the Wealden ; and MM. Cornet and 
Briart consider their formation to have commenced at the close 
of the carboniferous period, and to have continued, with all pro- 
bability, until the termination of the gault. J 
The flora of Aix-la-Chapelie was essentially terrestrial. A 
few algae occur, marine contemporaries of the land vegetation, 
which comprised numerous ferns, of which three of the genera 
are at present living : Asplenium, now European, and widely 
distributed ; Lygodium and Gleichenia, not European, the 
former mostly tropical, and the latter chiefly found in the 
South of Africa and Australia. The coniferae were tolerably 
abundant, including Glyptostrobus, Sequoia, and Araucaria, 
associated with some new types, as Gycadopsis. near to Sequoia, 
and Moriconia related to the Cupressineae in resembling Libo- 
eedrus and Thuiopsis of the present flora. Among the Mono- 
cotyledons, species of Pandanus or screw-pine and other forms 
occur. Of the dicotyledonous angiosperms, which constitute 
more than half of the flora, the Proteaceae — a family now re- 
stricted to South Africa, the Cape, and Australia — are very 
* “Elements of Geology/’ 1874, p. 280. 
t “ Bulletin Soc. Geol. de France,” 1875. 
X “ L’Aachenien et la limite entre le Jurassique et le Oretace dans 
l’Aisne et les Ardennes,” par M. Ch. Barrois. Bull. Geol. Soc. de France, 
3 ser., tome iii. p. 257. 
