Lanark Marl

The Municipality of the County of Antigonish operated a quarry in Lanark in the mid 1900s to provide marl to farmers for use as fertilizer.

Marl is a rock containing clay and calcium carbonate that is formed from the erosion and weathering of other rocks. As rocks break down, small sedimentary particles (i.e. sand, silt, and clay) pile up. Eventually, these particles can become compacted together to form a new rock.

The type of new rock formed depends on the original rock and the nature of the erosion/weathering. If the new rock contains predominantly clay and calcium carbonate (i.e. limestone), it is called marl.

(Weathering and erosion are similar geological processes, but they are not the same thing. Weathering degrades a rock without changing its location. Erosion, on the other hand, causes rocks, or particles of rock, to be carried away from their original locations and deposited elsewhere. For example, water getting into a rock and splitting it when it freezes is weathering because the rock stays in place. Water carrying pebbles and sand down a river is erosion because the location of the pebbles and sand changes.)

Because of how it forms, a marl deposit can contain marl with a soft, mud-like consistency, the result of more recent erosion/weathering, and marl that is solid rock (older material that has been compacted). The Lanark deposit contained both soft and hard marl.

Some of the Lanark quarry’s marl, which had turned to stone, was removed by blasting but much of it was extracted just by digging it out because it was soft.

The Municipality of the County of Antigonish opened the Lanark marl quarry about 1941. By 1943, the pit had advanced about 65 feet from the quarry’s entrance and it had an average width of about 25 feet. The northern face of the pit was 30 feet high.

The Inspector of Mines visited the quarry in July 1949 after receiving a complaint from Dr. George Smith, a chemist at the Department of Agriculture in Truro, that the quarry had safety issues. Dr. Smith was familiar with the quarry because he had done chemical analyses of samples from it.

At the time of his complaint, the quarry’s walls were 25-30 feet high and were nearly vertical, despite a government requirement that the walls be on a 70-degree angle to prevent any loose material falling and hurting someone.

Dr. Smith also complained that there was a large piece of overhanging rock which could fall. Clay bands in the marl also raised concerns that sections could slough off the sides without warning.

The Inspector wrote to the municipality that the angle of the quarry’s walls had to be fixed before “workmen are permitted to work in the pit.”

Dr. Smith was right to raise these concerns about the safety of the Lanark quarry at that time. Nova Scotia’s mining and quarrying industry has reduced its injury rate by 90% since the Westray public inquiry report was released in 1997, partly by ensuring operations do not make these sorts of design and operational mistakes. We believe the most important thing to come out of a mine is the miner, and our modern safety record reflects this.

A memo dated November 18, 1949, says about 4000 tons of marl were removed that year. A Department of Highways “shovel” (an excavator) extracted 1600 tons of soft marl in three days that fall. The marl was taken from the floor of the quarry and the excavator dug down about eight feet. Another Department of Highways machine extracted another 2000-2500 tons the week before the memo was written.

The November 18 memo said demand for marl was falling off as winter approached so the pit was expected to shut down within days.

The marl quarry was on Marl Road in Lanark. The original house on the property was built in 1876 by carpenter John MacGillivray. It was purchased in 1927 by the Canada Cement Company and ownership was taken over the following year by its subsidiary, the Nova Scotia Gypsum Company. One of the sheds on the property was used by the companies to store explosives for blasting gypsum.

There are extensive gypsum deposits in the area and the Canada Cement Company planned to establish a gypsum quarry because a small amount of gypsum is added in cement manufacturing to control the “setting” of cement. Without gypsum, the cement will harden immediately after mixing in water, leaving no time to transport or place the concrete.

The Canada Cement Company actually built a gypsum quarry in 1928 a little to the north, in Harbour Centre, but never operated it because the company made arrangements to obtain gypsum from the Cheticamp gypsum quarry instead. (See the story of the quarry that never was at See the story of the Cheticamp quarry at

The most common use for marl is as a fertilizer for soils that are deficient in calcium carbonate (aka lime). Nova Scotia has had many marl quarries to provide fertilizer. For example, another marl pit, on the farm of Dan H. MacIsaac in Brierly Brook, also in Antigonish County, produced about 800 tons in 1949. The marl was loosened by bulldozing it before removing it by hand-shovelling.

Our thanks to the Antigonish Heritage Museum ( for their assistance with research. Nova Scotia has many excellent local museums and historical societies that help keep our stories alive. Many of them are focussed on the province’s geology and mining history and are great sources of information.