810 REPORT— 1890. 
Algeria and Tunis abounds with choice marbles, the richest of which are those of 
Kleber, near Oran. The Mediterranean coast of Spain is nearly one continuous 
mass of marble, producing whites of excellent quality, which were used for 
building the Alhambra, and also all shades of reds, yellows, and greens. 
Rich red marbles of all sorts and mixtures are also found near the French 
coast of this sea. Italy is now the chief marble-producing country of the world; 
the quarries of Carrara and Monte Altissimo Serravezza produce more annually 
than all the rest of the quarries put together, and the various islands of this 
country possess valuable quarries, those of Sicily being of especial value. 
10. The supposed Volcanic Eruption of Cape Reykjanes. 
By Tsurest Anderson, M.D., B.Sc., and H. J. Jounston-Lavis, M.D. 
Tt is currently believed in Iceland, and was stated in some of the public prints 
at the time, that a volcanic eruption or earthquake had taken place at Cape 
Reykjanes in October 1887, by which a large new Gia or chasm had been formed 
separating a large rocky promontory, almost deserving the name of a mountain, 
from the main Cape on which the lighthouse stands. This chasm, at least 50 feet 
wide, was pointed out to the authors from a passing steamer, the captain declaring 
he remembered the rocks before they were rent asunder. Here, then, appeared a 
case of the formation of one of the Gids or chasms which form such a characteristic 
feature of Icelandic geology. ‘There are several such on the Reykjanzs peninsula, 
huge chasms, several feet wide and of unknown depth, stretching for miles across 
the lava deserts of which the district is composed. In this district they usually, 
though not always, have a throw of a few feet or yards, but one of those at 
Thingvalla, more in the centre of the island, the Allmanagia, has a throw of about 
100 feet. In this instance the authors are satisfied that the Gia is due to the 
unequal settling of a crust of lava, formed on the surface of a still fluid mass, 
which has found an outlet and flowed out after the solidification of the surface. 
They are not prepared, however, to say that this explanation will hold in the case of 
all the rifts on the Reykjanzs peninsula. Consequently, any clear case of the for- 
mation of a fresh Gia in strata long cooled and solidified would have been of great 
theoretical importance. 
From a careful examination of the locality it appears that no formation of a 
fresh Gid has taken place, but that certain small portions of the rock on which the 
lighthouse stands have been loosened, partly by ordinary denudation and partly by 
earthquakes, which are frequent here, and fallen on to the beach. The strata of 
partly consolidated volcanic ash, &c., are quite continuous in the end of the small 
cove or recess between the two large rocks above referred to. 
Photographs were shown on the screen illustrating these points and showing 
several real and spurious rifts, and the structure of the lighthouse rock, which is 
the remains of a dissected volcano. 
11. On Lepidophloios and Lepidodendron. 
By Wn. Casu, F.G.S., F.L.S., F.B.M.S., and Jas. Lomax. 
The genus Lepidophloios appears to have been established by Sternberg at a 
time when our knowledge of Carboniferous plants was based, for the most part, 
upon merely superficial characters and not upon the anatomical structure of the 
plants themselves. The two genera, Lepidodendron and Lepidophiotos, though 
long known to hold close affinities, are clearly separated by well-marked characters. 
In Lepidodendron the leaf-cushions are fusiform or quadrate, varying much in 
form, even in the same species, according to their posicion on the stem and 
conditions of growth. Situated on the cushions and generally above the centre is 
the leaf-scar proper, whose upper and lower boundary lines are usually more or less 
convex and unite in lateral angles. Within the leaf-scar are three punctiform 
cicatricules, the central of which is alone connected with the vascular system, the 
two lateral being probably glandular. The cones in some species are borne at the — 
