276 Reviews—The South Wales Coalfield, Milford. 
Passing to the Carboniferous rocks, we find the Carboniferous 
Limestone division also developed on the two sides of Milford Haven. 
To the north there is a limited development at Goultrop Roads, which 
is of interest from the point of view of tectonics. On the south side 
the Lower Limestone Shales ( Cleistopora zone) are succeeded by the 
Main Limestone, of which the lowest part only (Zaphrentis zone) is 
developed. The Millstone Grit oversteps the underlying rocks. As in 
the Haverfordwest area, it is separable into three divisions. 
The Coal-measures have a thickness of about 6,200 feet. The 
coals are anthracitic. At the time of the recent survey only one 
small windlass pit was at work, and the coal industry in the district 
seems ‘‘to have reached its zenith about the latter half of the 
eighteenth century’’. The fossil floras indicate that the Coal-measures 
here belong to the Middle ( Westphalian) division. 
A very interesting chapter treats of the Tectonics. One set of 
movements with lines of Caledonian trend is dominant in the north 
of the region, and affects rocks up to and including the Silurian strata, 
though movements occurring after the formation of the Lower Old 
Red Sandstone, and probably in the interval between its deposit and 
that of the Upper Old Red, have lines of Armorican trend, due possibly 
to pressure against a Pre-Cambrian ridge. ‘The Post-Carboniferous 
movements are dominant in the south. Some lines have a Caledonian 
direction, but the principal have an Armorican trend. 
Details are given of the interesting structures developed by the 
various movements. The most striking feature is the overthrust of 
Pre-Cambrian rocks over Carboniferous Limestone as seen in Goultrop 
Roads, accompanied, as before stated, by schistosity in the later rocks. 
This limestone had been observed by De la Beche before the middle of 
the last century. An excellent photograph of the section is given in 
plate iv of the present memoir. 
The superficial deposits are described in. ch. xiv. The South 
Welsh raised beach has been detected on Milford Haven and in 
Skokholm Island. As in the area to the east, there is evidence that 
the ice came from the north-west. Several far-travelled boulders, 
many apparently of Scottish origin, are found in the drifts. These 
drifts indicate that the glaciation extended to the south of Milford 
Haven. In Druidston Haven the Boulder-clay contains marine shells, 
some of which are characteristically Arctic. 
The economic products are described in ch. xv. 
The memoir is illustrated by thirty text-figures, maps, etc., and 
seven plates reproduced from photographs. The maps will be of 
special use at present, as the colour-printed 1 inch map of which the 
memoir is descriptive is not yet published. | 
To the general geologist the district is perhaps even more interesting 
than that to the east, and the Skomer yolcanic rocks, the marine 
Devonian sediments of Milford Haven, and the overthrust of Pre- 
Cambrian over Carboniferous rocks in Goultrop Roads are especially 
noteworthy. Furthermore, as will be seen from an inspection of the 
photographs, the coast scenery is of a very high character, and those ~ 
who love to combine study of geology with appreciation of scenery 
will not regret a visit to the district. To make this successful it will 
