Geology and Mineralogy. 145 
progress 1s even one-sixteenth of an inch a year, it would take for 
an addition of a single foot to its height one hundred and ninety 
years, and for five feet a thousand years. 
It is here to be considered that the thickness of a growing reef 
could not exceed twenty fathoms (except by the few feet added 
een beach and wind-drift accumulations), even if existing for 
oe of thousands of ears, unless there were at the same 
Ime a slowl progressing subsidence; so that if we know the 
possible rate of increase in a reef, we cannot infer from it the 
ney ae for any particular reef; for it may have been very 
. ; Slower than that. Without a subsidence in progress, the 
eel would increase only its breadth.—Dana’s Corals and Coral 
18. Revue de Géologie pour les années 1868 and 1869, par M. 
tT. Vol. viii, 1872. Paris (Dunod, 
in 
dia, Coal, b : i 
y Thomas Oldham; Geology of the Shillong Plateau 
by H.R. Medlicott; Part 2, the papers on the Kurhurban and 
mantrated by numerous plates; and Ser. vit, Kutch Fossils, some 
lary Crabs, by F. Stoliczka, also illustrated in excellent style. 
Birests , ALFRED C. SELwyn, F.G.S., 
ches Report of Progress for 1870-71, 352 pp., 8vo. 1872.— 
th he Survey, 
“ Progress of the Survey and on the Gold Fields of Quebec 
New 8 é runswick; by Mr. Roxss on Northwestern 
bar runswick; by Mr. Ricuarpson on the country north of 
Co e St. John; by Mr. Venn and 
Me’ putatio; by Mr. Broome on Phosphate of Lime and Mica; by 
alah ELL on the region north of Lake Superior. The most 
orate report is that of Messrs. Bailey and Matthew. Their 
on ame, and of the progress of discovery with reference to it, 
ae up, in succession, the Laurentian areas and rocks, t 
z : itneg or those regarded as probably of this system, the Prim- 
thes under the name of the St. John Group, the Upper Silurian, 
Me evonian, the Lower Carboniferous, the Carboniferous or Coal 
‘sures, and the Triassic or New Red Sandstone. eology 
M. Jour. Sct.—Tarrp Series, Vor. IV, No. 20.—Aveust, 1872, 
10 
