60 REPORT—1863. 
Carboniferous or Mountain Limestone (the oldest group of strata for our consider- 
ation) might be hastily passed over, but for its presenting in this northern district 
a transitional type between Scotland and the south of England no less important in 
its commercial aspect than interesting to the geologist in the various inquiries 
which it suggests. Turn to the Mendips, to Wales, or to Derbyshire, and we find 
the Carboniferous Limestone constituted almost exclusively of actual limestone- 
strata, amounting to from 300 or 400 to above 1500 feet in vertical thickness, and 
never exhibiting other than the smallest traces of beds of coal. But in Yorkshire 
a change sets in: the carboniferous action, if I may so term it, applies the thin end 
of the wedge, and small seams of coal, of but little value, are intercalated among 
the beds of limestone, and are associated with a large proportion of shale and sand- 
stone, stratified with a remarkable regularity. Advancing northward, these seams 
increase in number and importance. Throughout the great moorland region which 
culminates in Cross Tell, the same strata, rising from far beneath our feet as we 
stand here on the lower Tyne, emerge to the daylight, and compose the substance 
of the Pennine chain which, with its lofty and heather-purpled undulations, forms 
the broad dividing ridge of northern England. 
In the region of Weardale and Aldstone Moor, where in the becks and burns, 
and in the grout escarpment which towers above the valley of Eden, excellent ex- 
posures of the strata invite their study, the shales are often very similar to those of 
the coal-measures, though containing but few vegetable remains: the sandstones 
and grey beds frequently exhibit stems and fragments of plants familiar to us in the 
overlying strata, and the coal-seams are crowcoal or anthracite, resting on a bed of 
indurated silicious silt or of clay. 
Northward, however, of the great fault which runs nearly parallel to, but south 
of, the Newcastle and Carlisle Railway, the coal-seams become, and as it appears 
suddenly, bituminous, and the lower division of the limestone admits more numerous 
intercalations of shale, sandstone, and coal; and when we follow it to the upper 
district of the North Tyne, and beyond the river Coquet, the violent folding and 
contortion to which the strata have been subjected bring into view new basins or 
fields of coal. The true position of these is far beneath our ordinary measures, and 
has been recognized as such in Scotland, where they attain a vast importance. In 
the Berwick district, which has been minutely described by Mr. Boyd, it would 
appear that about 400 fathoms of carboniferous-limestone measures have been de- 
tailed below the WhinSill or basaltic bed, and about 100 fathoms above it, including 
in all twelve seams of coal of from two to four feet each. Certain of these, the 
Scremerston seams, appear to be remarkable in haying a limestone roof. For the 
details of another of these basins of the limestone-coals I may refer you to an ex- 
cellent paper by my indefatigable friend Mr. Nicholas Wood, published, as is Mr. 
Boyd’s paper, in the ‘ Transactions of the Institute of Mining Engineers.’ 
Let us pass from the upper beds of the limestone to the next overlying group of 
deposits. The millstone-grit or Farewell Rock, as it is sometimes called by col- 
liers, embraces a series of strata unproductive in coal, and in which conglomerates 
and coarse and silicious grits often preponderate. With this rugged crown many 
of the fell-tops are capped; but before it bends downwards to pass under the first 
strata of the coal-measures, we may frequently find with it strata of shale, and 
sandstone, and fire-clay, roughly similar to those of the true measures, yet present- 
ing to a practised eye peculiarities of structure and colour. 
As we descend eastward from the higher ground of the moorlands, on the edge 
of which the first or Brockwell seam of coal is traced, and as we find new and 
higher seams constantly succeeding, and the strata inclined regularly towards the 
sea, we pass into the midst of that tract which, extending from the river Coquet 
on the north to near the Tees on the south, for 50 miles in length, forms the great 
northern coal-field. The greatest thickness attained by this formation is probably 
not more than 2000 feet. But it would be vain for me, within a limited time, to 
offer _you details of the strata—a subject which has been amply treated by Mr. Bud- 
dle, Mr. Wood, Mr. T, Y. Hall, Mr. Greenwell, and others. “ Let it suffice to say 
that in this thickness there exist, associated with shales of many varieties and with 
fine-grained sandstones, some 57 beds of coal, from an inch thick upwards, com- 
prising in all 75 feet of coal; whilst those which are considered the workable seams 
