68 NATURAL SCIENCE. JAN., 
the natural history of successive periods; but from this broad point 
of view all sorts and conditions of life and of land and water would 
have to be considered. 
In the present work the author endeavours to picture the changes 
in the distribution of land and water, over the area now occupied by 
the British Islands, during each of the great epochs of time which 
make up our geological sequence. His task is a most difficult one, 
for few geologists have been tempted to draw boundary-lines to mark 
the former limits of formations, however well they may be acquainted 
with them. It is one thing to picture in the imagination former 
general geological conditions; it 1s quite another thing to draw the 
outlines of land and water and to fill in conjectural rivers and lakes. 
The subject, like discussions on theology, is apt to lead to almost 
endless diversity of opinion, for (as the author admits) the materials 
for forming a definite judgment are so imperfect. 
That his work is appreciated, is shown by the issue of a second 
edition, in which the author has added over a hundred pages of 
further information. Altogether there are fifteen plates drawn to show 
the geography of different epochs. Three of these are new, six 
remain the same as in the first edition, and six have been subject to 
alteration. Several other small maps and sections are printed with 
the text. One of the principal alterations is in the map of the 
Ordovician period (Arenig Epoch); we notice also that a small lake 
is introduced into the Devonshire and Cornish area, in the map that 
represents the Permian period. 
Whatever value the maps may possess, there can be no doubt 
that the author has brought together, in a most painstaking way, a 
large amount of material bearing on the physical geography of our 
bygone ages. He concludes with a chapter on the Supposed Per- 
manence of Continents and Oceans, and with an appendix on the 
Sub-oceanic Crust. 
Les ALPES FRANCAIS, LES MONTAGNES, LES EAuUX, LES GLACIERS, LES PHENo- 
MENES DE L’ATMOSPHERE. [Bibliothéque Scientifique Contemporaine.] By 
Albert Falsan. Pp. 288. Illustrated. Paris: J. B. Bailliére et Fils, 1893. 
Price 3fr. 50c. 
In a little volume of 280 pages, Monsieur Falsan hasgiven a readable 
account of the French Alps, their geology, physical geography, and 
meteorology. The author’s extensive experience and well-known 
writings will attest his competence to speak on the subject, and we 
need only add that the condensation from larger works has been 
carefully and judiciously made. The nature of Monsieur Falsan’s 
special studies leads to marked prominence being given to the glaciers 
and ancient glacial phenomena, and to the Tertiary geology of the 
Alps. The chapters on these subjects are particularly good, and to 
them the geologist will naturally turn. 
A CATALOGUE OF BRITISH JURASSIC GAsTEROPODA. By W. H. Hudleston, F.R.S., 
and Edward Wilson, F.G.S. Pp. xxxiv., 148. London: Dulau and Co., 1892. 
Price 7s. 6d. 
Tuts work, although it embraces a comparatively small section of 
our British Fossils, is a most important addition to that series which 
we hope will eventually replace the famous Morris’ Catalogue. Nearly 
forty years have elapsed since the second edition of Morris’ work was 
published. In that volume only five species of Gasteropoda are 
