518 _ Reviews—Guide to the Fossil Invertebrata. 
depths of 4,000 to 5,000 feet (as noted on p. 8). This floor rises in 
domes and bosses, and its proximity to the surface is indicated by 
inliers of altered killas or of the metamorphic aureole. The coarse 
and the somewhat later fine-grained granite are duly described; and 
the effects of fluoric and boric vapours that emanated from the granite 
prior to its complete cooling and consolidation are pointed out. The 
‘schorl rock’ and the variety known as luxullianite have been pro- 
duced by these pneumatolytic processes; while most of the mineral 
lodes which occur in the metamorphic aureole surrounding the granite 
are attributed to like agencies. In the luminous chapters on these 
subjects, written conjointly by Mr. Reid and Dr. Flett, there is much 
that advances one’s knowledge of these interesting phenomena. 
An account is given of the possible preservation of Eocene gravel 
under the sea not far from St. Michael’s Mount, and attention is 
directed to the phonolite of the Wolf Rock which is depicted in an 
inset on the colour-printed map, while its actual position is indicated 
in a small map on page 2._ This volcanic rock may be of Tertiary age, 
but we are at a loss to understand why ‘‘no special description of the 
phonolite of the Wolf Rock is needed here.’ Being regarded as 
belonging to the district a description would have been just as 
appropriate as that of the granites and greenstones. We find also 
a somewhat meagre account of the very interesting Pliocene strata of 
St. Erth. Surely a list of the commoner fossils should have been 
given to accompany the instructive description of the physical con- 
ditions under which the deposits were accumulated. 
The Appendix on Mining by Mr. MacAlister contains a full and 
well-illustrated account of the many mines and of the more important 
lodes, with much statistical information. 
An excellent colour-printed map accompanies this memoir. It is 
compounded of Sheets 351 and 358, and the price is 2s. 6d. 
IV.—A GuipE tro tHE Fosstz InvertesRaTE ANIMALS IN THE 
DEPARTMENT OF GEOLOGY AND PAL®ONTOLOGY IN THE BRITISH 
Museum (Naturat History), Cromwett Roap, Lonpoyn, 8.W. 
8vo; pp. 182, with 7 plates and 96 text-figures. London; 
printed by order of the Trustees. Price 1s. 
ONGRATULATIONS to Dr. Arthur Smith Woodward, F.R.S., the 
Keeper of Geology, on the issue of an entirely new guide to the 
Fossil Invertebrata, which we learn from the preface by Sir E. Ray= 
Lankester, the Director, has been written by Dr. Francis A. Bather, 
the Assistant Keeper, with the help of Mr. R. Bullen Newton, 
Mr. G. C. Crick, in the Mollusca; Mr. W. D. Lang, in the Bryozoa 
and Corals; Dr. W. T. Calman, in the Arthropoda. ‘Thanks are also 
given to Mr. S. 8. Buckman, Mr. H. W. Burrows, Mr. C. Davies 
Sherborn, and Mr. B. B. Woodward. 
Commencing with the stratigraphical series in Gallery XI, occupying 
the wall-cases on the west side we find a collection of the various 
kinds of rocks found in Britain, arranged in the order of their age by 
the late Mr. R. Etheridge, F.R.S. Along the top of the case is 
a diagram showing the succession of these rocks from the newest to 
