GEOLOGY
for example, for, although lead, zinc, barytes, and other minerals are known to occur, the veins are hardly profitable. Lead mining has been carried on at several places, as at Rimmington, near Clitheroe, but very little mining is done now. The Limestone of the Furness district is the great repository of iron ore, which has been deposited in it as the result of chemical replacement.
Iron Ore.—The output of Iron Ore, in the form mainly of hæmatite, in 1903, was 382,271 tons. The hæmatite occurs in masses filling up irregular cavities in the limestone. It is generally believed that the iron owes its position and condition where found to having been carried to the spot by underground waters in solution, and that a gradual displacement took place of the limestone by hæmatite. The original source of the iron was probably the red rocks which overlie the limestone, although it must not be forgotten that iron is a mineral universally diffused and therefore capable of being brought from many sources.
MISCELLANEOUS
Rock salt and brine to the amount of 216,785 tons was obtained in 1903 from the Triassic marls, whilst the older rocks in North Lancashire yielded 20,576 tons of slate and 1,300 tons of igneous rock. Gravel and sand was used to the extent of 50,673 tons.
If we tabulate the minerals and quantities mined in 1903 in Lancashire alone the result is:—
| Tons. | Tons. | ||
| Coal | 24,517,761 | Rock Salt and Brine | 216,785 |
| Clay | 1,418,340 | Gravel and Sand | 50,673 |
| Sandstone | 760,534 | Slate | 20,576 |
| Limestone | 612,427 | Igneous Rocks | 1,300 |
| Iron Ore | 382,271 | Iron Pyrites | 287 |
Giving a total output of 27,980,954 tons, and also finding employment for 102,298 people.
The total value of minerals raised in Lancashire during 1903 much exceeded £10,000,000.
Soil.—Most of the soil of Lancashire is cold, owing to the subsoil being in large part derived from and resting upon the boulder clay. As a result, Lancashire cannot claim a high position for agriculture.
On the limestone, the soil is thin, but usually covered with short, sweet turf, which makes it good for sheep. In the Coal Measures and Millstone Grit districts, the land is mainly cut up into grazing farms, whilst the maritime plain, with its underlying Trias, makes good meadow and pasture land, and here agriculture reaches its highest level.
Dependence of Scenery upon Geology.—In few counties is the relation of scenery to the geology better illustrated than here. North Lancashire, with its hard slates, grits, and interbedded volcanic series, rises into a bare mountainous country, and is geographically part and parcel of the rugged Lake district. Where the Carboniferous Limestone reaches the surface, the country is picturesquely scarred with mural cliffs, supporting an abundant vegetation, whilst the succeeding Millstone Grit and Coal Measure country rises into bleak brown moorlands, intersected by narrow valleys supporting a bare pasturage and grazing ground.
Many of the hills are step-like, owing to the shales weathering away into steep slopes, leaving the sandstone and grit beds standing out in high relief.
The softer Permian and Triassic rocks have been ground down to a low-lying plain, on which by skilful and diligent methods agriculture has made most progress.
ALLUVIAL DEPOSITS[1]
Above a horizontal plane, approximately marked by the 25-feet contour above Ordnance datum, the purely alluvial deposits of Lancashire are found in the river valleys, and are well represented in almost all valley bottoms and in the excavations of the Manchester Ship Canal.
The bottom lands are formed by accretion during flood overflows. Sometimes, as in the Lune, alluvial terraces occur at higher levels cut out of the drift. Outside these limited riverine deposits the soil of the country is largely formed by the subaërial crumbling of the boulder clays and sands, of which a mantle covers the country up to more than 300 feet above Ordnance datum.[2] This sheet of drift spreads over and obscures the pre-glacial topography of the county, so that what in former times was a diversified landscape, standing at a higher level relatively to the sea, is now a somewhat monotonous gently undulating plain—the characteristic feature of south-west Lancashire.
The second physical feature of this portion of the county is of more geological interest,
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