Revieiv of Recent Geological Literature. 317 
the marble thus treated assumed a chalky appearance, which was found 
to be due to the destruction bj- polj'sj-nthetic twinning of the continuity 
of the reflecting cleavage surfaces of calcite. Dry deformation at 400°C. 
produced foliation without any trace of cataclastic structure. As in ice, 
the higher temperature produced a greater plasticity of the grains and 
hence the ability to flow around each other. The addition of perco- 
lating water made no difference in the resulting structure. The cata- 
clastic structure was found to have weakened the crushing strength 
of the marble ; foliation to have weakened it very slightly ; but folia- 
tion produced with the accompaniment of percolating water strength- 
ened the stone. 
These deformations are found to be similar to those produced upon 
metals, and analogous structures are found in certain highly contorted 
limestones. It is interesting to note that the presence or absence of 
water made no difference in the structure, but it is possible that the 
pressure was so great as to mask or prevent the pos^ble effects of 
vater. These experiments were admirably planned and executed, and 
they thrown a little light on the difficult problem of the conditions which 
obtain m the deeper zones of the earth's crust. i. h. o. 
The Physiography of Acadia. By Regixald A. D.\ly. 'Bull. Mus. 
Comp. cool., Vol. XXXVIII. Gcol. scr.. Vol. V. Xn. 5. pp. 73-104, 
II pis.) 
This is the first coherent and serious presentation of the physio- 
graph}' of Nova Scotia and adjacent regions. One might wish that it 
were based upon a longer field study than a few days by rail and boat; 
but it is founded also upon an extensive knowledge of physiographic 
forms, and a close study of such maps as have been available. Fur- 
ther research will probably not alter the main thesis of the paper. It 
will, however, fill in many gaps: for the present study is only in out- 
line, and of necessity treats of the broader features of the country. It 
is to be hoped that it will be followed b}^ more detailed work in the 
same area, and an extension to peripheral regions. 
The country is divided into the southern plateau, the Cobequid pla- 
teau, the New Brunswick highlands, and the Triassic lava plateau cm- 
bracing North Mountain, Digby Neck and Long Island — all parts of a 
well made peneplain of probable Cretaceous age ; the Triassic lowlands, 
of Tertiary age ; and the Carboniferous lowlands, also of Tertiary age 
as regards denudation. The denudation is thought to have been sub- 
aerial, although other theories are carefully considered. 
The southern plateau is composed of the metamorphic gold-bearing 
series (Algonkian?) and Siluria and Devonian strata. The author 
omits a series of Cambro-Silurian rocks which are found in the eastern 
half of Nova Scotia. It is stated that each of these has been involved 
in a late Devonian mountain building. As it seems to the reviewer, 
field evidence has not yet shown that the Silurian and Devonian are 
structural units with the .gold series, or that the main mountain build- 
ing was Devonian. On the contrary, before the end of the Devonian, 
the auriferous veins had been injected into the lower member of the 
