NS3678 : Former cornstone workings on Carman Muir
taken 16 years ago, near to Renton, West Dunbartonshire, Scotland
It is located on a west-facing slope, the land gently rising to a wide summit area less than 100 metres to the east of this point. The pit contains several large mounds of stone, as shown here. Although not shown in this photograph, the places where the stone has been quarried can be seen in several places along the edge of the pit; a few other sites of excavation can be found nearby, such as NS3678 : Pit from former limestone quarrying.
A fellow contributor brought to my attention a relevant article by naturalist John Mitchell: "Old Cornstone Workings in Dunbartonshire and West Stirlingshire, with Notes on their Associated Flora" ("Glasgow Naturalist", Volume 22(5), 1995, pp485-494).
According to that article, cornstone, which has the alternative name caliche, is a terrestrial rather than a marine limestone. It was burned to produce lime for use in the cultivation of cereal crops; this was a folk industry rather than a large-scale commercial venture, and the practice rapidly tailed off after the start of the nineteenth century.
The article lists several former cornstone workings, including one at Kipperoch (NS 368 783), corresponding to the site shown in my photograph. The article also mentions the remains of a lime kiln, which I did not locate until later: Link
As the same article explains, former cornstone workings are of ecological importance because the calcium carbonate leached from the rocks gives rise to a less acidic habitat, which can support various plant species that would not otherwise occur in the area (the lime-enriched habitat here is rather different from the surrounding area, which consists, in general, of fairly acidic heathland).
In the background, on the other side of the River Clyde, the area around Port Glasgow and Gourock is visible.
Cornstone (a kind of limestone) was quarried from various locations on Carman Muir, to be burned for lime, but the industry was centred on this particular knoll: a ruined lime-kiln can be seen on its northern side, and there are extensive spoil mounds and signs of quarrying nearby. See Link
See Link (in a Geograph article) for further information, and Link
The topography of the parts of Carman Muir to the south of Cardross Road is determined to a large extent by cornstone deposits, which outcrop in places. Cornstone is an impure granular limestone, a fossil soil. Old quarry pits (probably worked before the nineteenth century) and possible test pits can be seen along the lines of these deposits; they are indicated by light blue marker pins on the annotated satellite view, and the cornstone outcrops are marked by orange pins.
This area, lying to the south of Cardross Road, exemplifies what the British Geological Survey refers to as the Kinnesswood Formation (see Link
Beside and to the north of Cardross Road are outcrops of sandstone rather than cornstone. The sandstone is best seen along a line of outcrops and pits beside the road (these are indicated by reddish marker pins on the annotated satellite view). Another prominent example lies at the ENE end of that line: a large disused red sandstone quarry, the old Fairy Knowe Quarry (later known as Carman Quarry) – Link – at NS36967900. This area beside and to the north of the road exemplifies the Stockiemuir Sandstone Formation (see Link
Both north and south of the road, the strata in this area generally dip at an angle of from 10° to 20° from the horizontal, descending towards the SSE; the Stockiemuir Sandstone Formation that is exposed beside and to the north of the road underlies the cornstone-containing Kinnesswood Formation to the south of the road.
The annotated satellite view also includes markers for various antiquities in the area:
● Ancient cairns: Link
● Circular enclosure: Link (originally reported as a hut circle)
● Carman (house): Link
● Carman (enclosure): Link
● Carman (field system): Link
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- Grid Square
- NS3678, 137 images (more nearby 🔍)
- Photographer
- Lairich Rig (more nearby)
- Date Taken
- Monday, 23 February, 2009 (more nearby)
- Submitted
- Wednesday, 25 February, 2009
- Subject Location
-
OSGB36:
NS 3683 7835 [10m precision]
WGS84: 55:58.2202N 4:36.9654W - Camera Location
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OSGB36: NS 3685 7835
- View Direction
- WEST (about 270 degrees)
