222 Geological Society. 
Description of a new genus belonging to the natural family 
of plants called Scrophularine, by Mr. David Don, Libr. L.S. 
Mr. Don proposes to name this genus Lophospermum, and in 
this paper points out its affinity to Antirrhinum and Maurandia, 
from both which, however, it is abundantly characterized by 
its flat winged seeds and campanulate corolla. The essential 
characters of the genus are as follows :—Calyx 5-partitus, 
Corolla campanulata: limbo 5-lobo, subequali. Capsula bi- 
locularis, irregulariter dehiscens. Semina imbricata, membra- 
naceo-alata. 
The genus consists of two species, both of them natives of 
Mexico, where they were discovered by the Spanish botanists 
Sessé and Mocinno, and which Mr. Don has named Lopho- 
spermum scandens and physalodes. 
A review of the genus Combretum, by Mr. George Don, 
A.L.S. 
The author here describes thirty-eight species of this inter- 
esting and beautiful genus, exclusive of six doubtful species 
enumerated by Dr. Roxburgh in the Hortus Bengalensis, In 
the Systema Vegetabilium ot Professor Sprengel, which is the 
latest general work, only six species are enumerated. 
GEOLOGICAL SOCIETY. 
March 3.—The reading of Sir A. Crichton’s paper On the 
Tanuus Mountains in Nassau was concluded. 
The great mountain groups forming the Tanuus, are por- 
tions of that vast chain which crosses the Rhine to Valen- 
ciennes; and in the duchy of Nassau they are composed of 
transition and trap rocks: they here separate into two ranges, 
nearly at right angles to each other. ‘The southern chain lies 
on the north of Mayence and Frankfort, and its highest point 
is the Feldberg, 2600 feet above the level of the Mayne. The 
northern chain includes the Westervald, celebrated for its 
brown coal. The strata of the southern face of the former 
chain, consist of tale and quartz-slate dipping north-west ; 
whilst those of the northern face are of grauwacké and clay 
slate, inclining upwards south-east. The summit is a decom- 
posing quartz rock, containing talc and iron, the sides and 
base of the mountain being formed of talc and slate. The 
baths of Schlangenbad are surrounded by slaty quartz: 
quartz conglomerates occur near the foot of the southern 
chain; where also a thick bed of sandstone, resembling our 
new-red-sandstone, rests upon the calcareous deposits of the 
valley of the Mayne, quarries of which are seen at Wisbaden. 
The valley of the Mayne, which is interposed between the 
northern and southern chains, is chiefly occupied by low hills 
of 
