176 Reviews—New Survey Maps and Memoirs. 
_ D.Se., and D. A. MacAutsrer, A.R.S.M. 1906, price 8s., 94 inches 
by 6 inches; pp. iv-+ 131, with 6 plates (photographic process) 
and 23 figures. Pages 1- 90 are devoted to Geology ; pp. 91-119 
form Appendix I, Mines; pp. 120-122 form Appendix ils 
Bibliography ; pp. 128-181, "Index. In explanation of Sheet 346. 
MONG the recent publications of the Geological Survey are Sheets 
346 (Newquay) and 352 (Falmouth) of the New Series of one 
inch to one mile (g3360) colour-printed maps of England and Wales, 
both dated 1906, price 1s. 6d. each. ‘The area comprised in Sheet 352 
extends from Gerrans Bay on the east to (and inclusive of) Camborne 
on the west, from Porthtowan on the north to Falmouth Bay on the 
south. The formations represented are 1n ascending order. I. The 
Mylor Series; in the south-west of the map it occupies almost two- 
thirds of the area represented, if we disregard the great granite 
masses intrusive in it. The Mylor. Series encloses the various green- 
stones, the greater portion of the elvan dykes, and, in conjunction 
with the eranites, almost the whole of the mineral lodes. II. The 
Falmouth Series occurs in several minor and three considerable areas— 
(1) between Porthtowan and Reskajeage Downs; (2) between St. Day 
and Truro; (3) on the coast of Falmouth Bay. II1. The Porthscatho 
Series occupies a large area in the east and extends in a mile-wide 
band along the north of the area. IV. The Veryan Series is restricted 
on the map to a triangular tract of about half a square mile on 
Gerrans Bay. 
In the legend of the map the preceding formations are merely 
bracketed together as Lower Paleozoic, but in the corresponding 
memoir they, together with the Lower Devonian Grampound Beds, 
which form a mile-wide strip along the northern margin of the map 
area, are grouped together as Killas, viz. slate deposits. 
A deposit of quartz gravel, occupying an area less than half a mile 
in length and about a quarter of a mile in breadth, occurs near 
Polcrebo, in the heart of the granite district, and is mapped as 
Pliocene. ‘‘ Raised Beaches, Head, Alluvium, and Blown Sand” 
complete the list of sedimentary formations. Perhaps the most 
interesting feature of the map is the rudely circular Carnmenellis boss 
of muscovite-biotite granite, about 9 miles in diameter, which occupies 
the south-west of the map. Like the two smaller adjacent granite 
masses of Carn Brea and Carn Marth, it is surrounded by an aureole of 
metamorphism. Intrusions of greenstone (largely referable to the 
group of epidiorites), elvan, or quartz-porphyry dykes, the latter 
generally trending about east-north-east (like the mineral lodes), anid 
mica traps or minettes are also shown. The numerous mineral lodes 
of the area are almost entirely confined to the western district, and are 
mainly restricted to the neighbourhood of the granite, but continue to 
occur for a distance of 4 miles eastward of the granite. 
A section below the map shows the structure of the country along 
a line from west-north-west to east-south-east, from Reskajeage Downs 
through Dolcoath Mine, Carn Brea, and Carnmenellis granite to 
Falmouth and Pendennis Point. 
Sheet 346 (Newquay) shows the country immediately to north of 
that represented in Sheet 352, and includes Watergate Bay, Newquay, 
