TRANSACTIONS OF SECTION OC. 479 
coalfield may be divided, the Central or Ashby area of so-called unproductive 
measures yielded no fossils, either plant or animal, and the age of the beds, 
whether Lower or Middle Coal Measures, remains an open question. The 
Eastern or Cole Orton area presents serious difficulties to the collector, being 
for the most part a concealed coalfield worked under a thick Triassic cover, and 
the results obtained were merely of local interest. Attention was finally concen- 
trated on the western or Moira area, where the sequence is more complete than 
in the rest of the coalfield, and exposures are much more numerous. Many 
fossiliferous horizons were discovered, which yielded a rich flora, several rare 
Crustacea, some fragmentary fish-remains, numerous freshwater lamellibranchiata, 
and above all an abundant marine fauna from several different horizons and 
many localities. Unfortunately, no indication of the well-known Ganister 
Coal Marine Bed (Alton Coal of Nottinghamshire) has yet been found in 
Leicestershire. 
The thickest Marine Bed, which also fas the richest fauna, occurs in the 
higher portion of the Middle Coal Measures about 260 yards above the Moira 
Main Coal; it crops out at many places in the Moira, Swadlincote, Church- 
Gresley, and Woodville district, and the outcrop has been laid down on the 
6-inch scale. 
Such mapping is of value since for want of an index bed it has hitherto been 
impossible to map any seam of coal above the Main Coal owing to the variable 
character of the beds in the higher portion of the Coal Measures, and the 
structure of this part of the coalfield was, therefore, imperfectly understood. 
Using this Marine Bed as an index bed, we can now fix the position in the 
sequence of the Moira Sandstones and Grits and of the valuable series of pot, 
pipe, and fireclays on which the prosperity of this district so largely depends. 
The main interest of this Marine Bed is that in stratigraphical position and in 
faunal contents it is comparable with the Gin Mine Marine Bed of the North 
Staffordshire coalfield, with the Mansfield Marine Bed of the Yorkshire and 
Nottinghamshire coalfield, and with the Pennystone Ironstone Marine Bed of 
Coalbrookdale. 
The following is a correlation of the Productive Coal Measures of the East 
Midland coalfields, based upon the chief marine transgressions :— 
Yorkshire and Nottinghamshire West Leicestershire Warwickshire 
Coalfield Coalfield Coalfield 
‘Mansfield Marine Bed | Pottery Clay Marine | Doubtful 
Bed 
Strata, 930 feet Strata, 750 feet Strata, : 
thickness | Middle 
Middle and | varine Bed 300 feet 
Marine Bed above 
unknown \Coal 
Marine Bed / Measures. 
reve Coal) below the Top Hard the Main Coal above the 
easures. 
coal Seven-foot 
Strata, 1,600 feet Strata, thickness un- Coal 
known 
Marine Bed above the Doubtful Absent 
Alton (Ganister) 
coal 
In conclusion, it was shown that in colour, mode of weathering, and other 
characteristics these Marine Beds are in every way comparable with modern 
‘Blue Muds.’ 
4. On Systems of Folding in the Paleozoic and Newer Rocks. 
By Grorce Barrow. 
In a paper published by the Geologists’ Association the author has given a 
brief outline of the nature of the crystalline area of the Highlands and shown 
that it consists of three great lenticular masses of thermally altered rocks. It 
