Part LV. Szor.i.§2.] EOCENE, 849 
than to that of the lower Eocene. The Mons limestone has thus been 
cited as an illustration of Barrande’s doctrine of colonies. 
Above this deposit comes the “ Systéme Heersien,” so named from its 
development at Heers, in Limbourg. With a total depth of about 100 
feet, it consists of (1) a lower division of sandy beds, with Cyprina 
planata, C. Morrisi, Modiola elegans, and other marine shells, some of which 
oceur in the Thanet sand of England and the Sables de Bracheux: and 
(2) an upper division of marls, containing, besides some of the marine 
shells found in the lower division, numerous remains of a terrestria] 
vegetation (Osmunda eocenica, Chamecyparis belgica, Poacites latissimus, 
and species of Quercus, Salix, Cinnamomum, Laurus, Viburnum, Hedera, 
Aralia, &c.).? 
The “ Systeme Landenien,” corresponding to the Thanet and Wool- 
wich and Reading beds of England and the Sables de Bracheux, Argile 
plastique, and Lignites du Soissonnais of France, is divisible into two 
stages : Ist, Lower marine gravels, conglomerates, sandstones, marls, &e., 
with badly preserved fossils, among which are Turritella bellovacina, 
Cucullza decussata (crassatina), Cardium Edwardsi, Cyprina planata, Cor- 
bula regulbiensis, Pholadomya Konincki ; 2nd, Upper fluvio-marine sands, 
sandstones, marls, and lignites containing Melania inquinata, Melanopsis 
buccinoides, Cerithiwm funatum, Ostrea bellovacina, Cyrena cuneiformis, with 
leaves and stems of terrestrial plants. 
The “ Systéme Ypresien ” consists of a great series of clays and sands 
answering generally to the London Clay, but not represented in France. 
Ji is divided into two stages: 1st, Lower stiff grey or brown clay, some- 
times becoming sandy, and probably an eastward extension of the London | 
Clay. The break between this deposit and the top of the Landenian 
beds below is regarded as filled up by the Oldhaven beds of the London 
basin. The only recorded fossils are foraminifera agreeing with those 
of the London Clay. 2nd, Upper sands with occasional lenticular inter- 
calations of thin greyish-green clays, with abundant fossils, the most 
frequent of which are Nummulites planulata (forming aggregated masses), 
Turritella edita, T. hybrida, Vermetus bognorensis, Pecten corneus, Pectun- 
culus decussatus, Lucina squamula, Ditrupa plana. Out of 72 species of 
molluscs, 45 are found also in the Sables de Cuise and 20 in the London 
Clay. 
The “ Systéme Paniselien,” so named from Mont Panisel near Mons, 
consists chiefly of sandy deposits not markedly fossiliferous, but contain- 
ing among other forms, Rostellaria fissurella, Voluta elevata, Turritella 
Dixoni, Cytherea ambigua, Lucina squamula. Out of 129 species of mollusca 
found in this deposit, 91 appear in the Sables de Cuise and only 36 
pass up into the Calcaire Grossier. Hence the Paniselian beds are placed 
at the top of the Lower Eocene stages of Belgium. 
Middle——This division in the Paris basin is formed by the cha- 
racteristic, prodigiously fossiliferous Calcaire Grossier, which is sub- 
divided as under :* 
1 Briart et Cornet, Mém. Couronn. Acad. Roy. Belg. xxxvi. (1870); xxxvii. (1873) ; 
xliii. (1880). Mourlon, Geol. Belg. 1880, p.192. Hébert (Ann. Sciences Geol. iy. 1873; 
p. 15) has noticed an affinity to the uppermost Cretaceous fauna of Paris. 
2 De Saporta et Marion, Mém. Cour. Acad. Belg. xli. (1878). 
3 Mourlon, Geol. Belg. p. 211. 
+ Dollfuss, Bull. Soc. Géol. France, 3e sér. vi. (1878), p. 269. 
