556 Notices of Memoirs—Professor W. 8. Boulton— 
Dr. Gibson, after a detailed survey of the North Staffordshire 
Coalfield, where the Middle and Upper Coal-measures are fully and 
typically developed, asserts that ‘‘no break has been detected in the 
Coal-measure sequence’’;! and a like conclusion is to be drawn from 
the work of the Government surveyors and from borings in the 
Yorkshire, Derby, and Nottingham Coalfield and that of East 
Warwickshire. 
Mr. Henry Kay *? would fix a local unconformity at the base of the 
Halesowen Sandstone of South Staffordshire, and another at the base 
of the Keele Beds (or so-called Lower Permian Marls); while in the 
Coalbrookdale Coalfield the well-known Symon Fault, described by 
Marcus Scott as a great erosion-channel in the Middle or Productive- 
measures, subsequently filled up by the unproductive Upper Coal- 
measures,*® was interpreted by W.J. Clarke in 1901 * as a pronounced 
unconformity, a view which has been generally accepted ever since, 
and which was eagerly seized upon by those who hold that the 
Malvernian disturbance occurred at this time. 
The plate which illustrates Marcus Scott’s paper on the Symon 
Fault *° shows the upper beds plotted out from the lowest workable 
seam in the older measures, which he assumes to be horizontal 
(their original position); while Clarke, using Scott’s data, plots his 
sections from the base of the Upper-measures, which he uses as 
a horizontal datum-line.* Incidentally I may remark that in both 
cases the sections are drawn with a much-exaggerated vertical scale, 
and, of course, correspondingly exaggerated dips. 
In my opinion, both these interpretations are misleading (apart 
from the question of seale), because in neither case is the adoption of 
the horizotal datum-line strictly justified by the facts. In the one 
case the curvature of the basin is made too great, and in the other 
the dips in the Middle-measures are unduly increased ; for, as mining 
plans show, the base of the Upper-measures is by no means horizontal. 
The fact is that the undulations in the measures throughout the 
_ coalfield are extremely slight, there being scarcely any perceptible 
dip in the strata, as noted by Scott, except near what is called the 
‘* Limestone Fault’’, where the dips, as will presently appear, can 
be otherwise accounted for. Furthermore, there is a significant 
absence of faults other than those which affect Middle and Upper- 
measures equally. 
I believe there is another and a simpler explanation of this classic 
disturbance, and one which harmonizes, in part, the views of both 
Scott and Clarke; and at the same time helps to give us a reasonable 
interpretation of the apparently conflicting statements which have 
been made by working geologists respecting the relationship of the 
Coal-measure divisions in the Midlands. 
The Keuper Marls of the Midlands occur either in horizontal or 
1 Q.J.G.S., vol. lvii, p. 264, 1901. 
2'Q.J.G.8., vol. Ixix, pp. 433-53, 1913. 
3 Q.J.G.S., vol. xvii, pp. 457-67, 1861. 
4 Q.J.G.S., vol. lvii, pp. 86-95, 1901. 
> Thid. 
8 Tbid. 
