Geology and topography have played an important role in the development of Leeds and its surrounding area. Sandstones suitable for all types of construction, clays for brick making, coal for fuel and minerals for iron making were all readily available locally. The rivers Aire and Calder and their tributaries, flowing in narrow, steep sided valleys, provided water for power, industrial processes and as means of transport for raw materials and products.
The site of Kirkstall Abbey, one of the oldest buildings in Leeds, was selected partly due to nearby outcrops of the Rough Rock, one of the gritstones, typical of the Millstone Grit Group, which was used for its construction.
Fig 42 A small quarry in Millstone Grit Group, Rough Rock gritstones. Roundhay Park
As industry developed and towns and villages expanded many small quarries (Fig 42) were opened close to the place where the stone was required but, by the mid-nineteenth century, as demand increased and mechanisation and better transport were introduced, these were replaced by fewer, larger quarries. (Fig 43)
Fig 43 A large quarry in Millstone Grit, Rough Rock gritstone. Woodside Quarry, Horsforth.
The Millstone Grit Group sandstones are strong, coarse to medium-grained and occur in thick beds, making them ideal for building and engineering purposes. Their coarse nature however meant they could not be used where a smooth finish was required or for finely carved, decorative work. For this type of work the Coal Measure Group sandstones,which are generally medium-fine grained, were used.Some of these sandstones were flagstones, that are easily split into thin slabs making them ideal for paving and roofing. Many of the older civic and commercial buildings in Leeds, of which Leeds Town Hall (Fig 44) is an excellent example, show a combination of large blocks of coarse-grained sandstones forming their basal layers with fine grained sandstones, often with ornate carvings, their upper portions.
Fig 44 Leeds Town Hall. Large blocks of coarse-grained gritstones have been used for the lower courses with smaller blocks of finer grained sandstones for those above where a smooth finish and decorative work was required.
Stone was not just used locally but exported to other parts of the country and abroad. Millstone Grit, Rough Rock was particularly sought after and stone from Bramley Fall Quarries (Fig 45) was used for many important projects. Notable ones were the original Euston Station and Millwall Docks in London and docks in Mumbai, India.
Fig 45 Bramley Fall Quarries supplied stone for many prestigious buildings and structures at home and abroad.
Today there are still some quarries producing dimensional sandstone(Fig 46) with much of it being used in restoration of, or extensions to, older buildings.
Fig 46 Bolton Woods Quarry Bradford which still produces dimensional stone.
Being relatively soft, well sorted and made of almost pure quartz, the Permian age, desert sands, were mined in the past as for moulding sand in the iron industry and for glass making.
Coal has been mined in the district, possibly since Roman times, and the occurrence of abundant, easily accessible reserves across the southern part of the district was vital to the growth of its industries and population. Steam replaced waterpower in the woollen mills that had grown along the Aire and Calder valleys and their tributaries, and then provided the power to enable mines to reach deeper reserves and for the transport to convey their products. Initially coal was dug from shallow open pits where it outcropped or was close to the surface. As these shallow reserves were exhausted the coal seams were followed underground, accessed by deeper and deeper mines. Since the 1940’s increasing costs of deep mining and improvements in machinery saw a move to large scale opencast mines. (Fig 47)
Fig 47 St Aidan’s Opencast coal mine. Astley. Leeds. Closed in 2002 and is now a nature reserve.
All mining has now ceased in the district and much of the evidence of its existence cleared. The exception to this is Caphouse Colliery which now, as the National Mining Museum, still provides and insight, including underground experiences, of this once great industry.
Mudrocks and Clays
Brick took over from stone to satisfy the growing demand for houses during late Victorian times. Brick was a much cheaper alternative than stone and the mudrockand clay required were readily available in the Quaternary and Coal Measure Group rocks, which also supplied the coal to fire the kilns. Clays were also used for making pottery and terracotta tiles with Leeds Pottery which made white, ‘Leeds Creamware’ and Burmantofts Pottery which made coloured, glazed tiles and bricks known as ‘faience’, the best known. (Fig 48)
Fig 48 Burmantofts Pottery. Leeds
As in stone quarrying, initially there were many small clay pits and kilns opened adjacent to where the bricks were required but these were replaced by larger operations as mechanisation and transport improved.Today these industries have all but disappeared although there are quarries where reserves have been mothballed.
Ironstones occur in the mudrocks of the Coal Measure Group either as thin beds or nodules. They were dug from quarries and mines and provided the raw material for the iron industry that Leeds became famous for. However, the reserves of were limited, and it was not long before they were exhausted, and ore had to be imported from elsewhere.
The Permian age limestone was worked from many quarries along its outcrop (Fig 49) as a building stone and for burning to make agricultural lime.
Fig 49 Abandoned limestone quarry. Micklefield.
As well as used for building in villages such as Wetherby, Bramham and Aberford, (Fig 50) its attractive pale-yellow colour, ease of extraction and ability to take fine carving made it worth transporting considerable distances in the past. York Minster was largely built of stone from a quarry near Sherburn and it was also used in the construction of Eton College. The same rock, but from quarries in south Yorkshire, was used to build the Houses of Parliament. Today the main use of this stone is for aggregate.
Fig 50 Aberford Almhouses. Built of local dolomitic limestone.
Sands and Gravels
The youngest geological materials are those left by melting ice. Meltwater rivers surging through the Calder, Aire, and Wharfe valleys, and the lakes that once flooded their lower reaches, left thick accumulations of sands and gravels which were dug from open pits as aggregates for the construction industry. Much of this work has now stopped and the flooded quarries (Fig 51) used for recreation or as wildlife reserves.
Fig 51 Flooded gravel pits used for sailing. Otley.
Traditionally the bulk of the district’s public water came from reservoirs with the rest from rivers and boreholes, but with the development of a grid system it can now be transferred from sources much further away. Reservoirs are mostly sited on rocks of the Millstone Grit Group to the north and west of the district with water being transferred to the urban areas by a combination of the rivers that flow from them and pipelines.
Boreholes exploiting water held in porous rocks below the surface (aquifers) mainly supply individual industrial and agricultural customers. In areas underlain by Carboniferous rocks, sandstonesof the Millstone Grit Group form the best aquifers as their water is generally of better quality than that extracted from sandstones of the Coal Measure Group. The Permian limestones in the east of the area form a good aquifer but the water is ‘hard’ (has a high mineral content) and so is not used in public water supply. One advantage of this water however is that it makes good beer – which accounts for the breweries in Tadcaster!