312 
POPULAR SCIENCE REYIEW. 
being partly due to tbe inevitable breakage and disturbance of the rocks 
near the line of fracture, and partly to the fact that rocks of unequal hard- 
ness were often opposed to one another for a great distance in consequence 
of the displacement. This latter cause was specially manifest in the case of 
Derwentwater — one side of which was composed of the comparatively 
yielding Skiddaw slates, and the other of the igneous series of the green 
slates and porphyries. And there were unmistakable proofs that this was 
due to faulting, and 'was not caused by the "u^ant of conformability, which 
the author had recently shown to exist between the two formations in 
question. 
Fossil Plants of Greenland. — In his report presented to the Royal Society 
(April 7), Professor Oswald Heer, in his summary of the botanical results 
of his late arctic expedition, announced the identification of fourteen species 
from Disco Island, among which Platanus Guillelmo} (Gopp.) and Sequoia 
CoutesicB (Hr.) are the most common. Of Magnolia Inglefieldi, a 
species originally identified by means of leaves found at Atanekerdluk, two 
cones were found in the Disco beds, thus corroborating the previous deter- 
mination, and proving that this splendid evergreen ripened its fruit so far 
north as on the parallel of 70^. Seven out of the Disco species occur also 
at Atanekerdluk, and eight agi-ee with those of the Lower Miocene of 
Europe. The age of the deposit is accordingly well ascertained. The col- 
lection from Atanekerdluk contains seventy-three species, of which twenty- 
five are new to Greenland. Some of these are known European forms, 
especially Smilax grandifolia, which, at the Miocene epoch, occurred over the 
whole of Europe. Of Sequoia Langsdorffii, as was to be expected, abundant 
evidence has been accumulated, sho’wing how favourable the conditions of 
climate and soil were to its growth. Among the most interesting specimens 
are the flowers and fruit of a chestnut, the latter in a very imperfect condi- 
tion. The discovery of these proves that the deposits in which they are 
found were formed at different seasons, in spring as well as in autumn. The 
Miocene plants of Greenland have now reached the number of 137 species, 
and those of the Arctic Miocene flora 11>4. Of the Greenland species 46, or 
exactly one-third, agree with those of the Miocene deposits of Europe. 
The determination of the age of the beds as Lower Miocene has accord- 
ingly been confirmed. Four of the species agree with those of Bovey 
Tracey, among them Sequoia CoutesicCj the commonest tree in the latter 
locality. In concluding the first part of his paper, the fiuthor ofiers a resume 
of the grounds on which the determinations of the species have been based. 
Seventeen species are represented by the leaves and organs of fructification 
among the Greenland specimens. Ten species are only represented by leaves 
in Greenland, but their organs of fructification occur elsewhere. Seventeen 
species, of those of which only leaves are found, exhibit, however, such 
marked characteristics, tliat there can be no doubt about their identification. 
Five cryptogams have been satisfiictorily recognised. Accordingly, though 
it must be allowed that the systematic position of many of the plants from 
North Greenland is as yet uncertain, yet the considerable number of abso- 
lutely identified species which can be produced enables us to form a clear 
idea of the Miocene flora of North Greenland. 
Subterranean Lava Tide «. — The idea of a regular tidal flow of fluid lava is 
