As I spend my days walking up and down the hill of the National Museum of Bermuda, I find myself marvelling at the chisel marks on the limestone cliffs and walls. The entire Bermuda Royal Naval Dockyard was initially quarried out by the hands of enslaved and freed black Bermudian men and later by British convict labourers who first arrived in 1824. Day after day, they blasted rock, quarried stone, and shaped the hard limestone blocks that formed the Dockyard’s massive fortifications and naval infrastructure. While a number of buildings still remain, many fell into disrepair after the Dockyard closed in 1951. Some have disappeared entirely, others were abandoned, and many still stand in various stages of decay, while a number have been restored for tourism, commercial, or heritage purposes. Even though, I’ve always known that limestone lies at the very foundation of the Island’s archipelago I couldn’t help but wonder how limestone also became a building block for Bermuda’s culture, heritage and traditions.
Over 30 million years ago, a deep-sea volcano erupted, creating the Bermuda Seamount, which later eroded and subsided beneath the ocean. Over this submerged platform, marine organisms and wind-blown sands produced the limestone that now forms the Island’s surface creating an archipelago of 181 islands. Commonly known as Bermuda stone, this limestone has shaped the island both geologically and economically. Geologically, it forms the foundation of the islands and underlies the extensive coral‑reef system that naturally protects Bermuda’s coastline. Economically, Bermuda stone became an essential local building material, abundant and workable it became the standard stone for building the Island’s infrastructure.
Limestone has a strong composition, which has proved invaluable in adapting to Bermuda’s sub-tropical climate and penchant for hurricanes. As the limestone is quarried from the earth, it hardens and is able to withstand natural disasters the Island may face. Bermuda stone is naturally porous which allows heat to escape, keeping homes cool in the summer. This was especially useful in the days before the Island became accustomed to air conditioning. Its porous nature is also utilised in Bermuda’s water catchment system, filtering and purifying the rainwater before it reaches the water tank.
A traditional Bermuda roof and chimney, circa 1910–1950s. The stepped limestone roof, central to the Island’s water catchment system, was coated with a white limewash made from local limekilns.
Quarrying and stonecutting on the Island began in the 17th century. Limestone was vital in creating all the fortifications around Bermuda during its tenure as Britain’s primary imperial fortress in the Atlantic, especially the hard Bermuda limestone . The establishment of the Bermuda colony increased the need for permanent structures that could withstand hurricanes, winters, and any potential warfare. The earliest limestone structures would have been fortifications such as Fort St. Catherine, completed in 1614, and government buildings such as the State House, completed in 1620, and currently still standing.
The State House, built in the early 17th century, showcases limestone construction and colonial architecture adapted to the island’s subtropical climate.
By the early 18th century, residents began replacing their wooden houses with limestone ones. Switching to Bermuda Stone was incentivised by the Governor, in part due to its ability to weather Bermuda’s climate but also to dedicate more timber resources to shipbuilding, a key export for the developing Island. At this time, most structures were made of hard limestone, a stronger, less porous type of limestone. By the 19-20th century, most structures in Bermuda are made of softer grade of limestone, known as sandstone.
In modernity, most structures are made of concrete as there are only a few operational quarries on the Island. The process of removing limestone form the ground is called quarrying. Quarrying involved cutting 12-15ft blocks out of a quarry using a chisel and 8ft saws. From there, they would cut the blocks into smaller building blocks. A single stone block could yield 1200-1600 Bermuda stone blocks or 1000 pieces of Bermuda roof slate, which was used in roofing. One quarry could employ between 30 and 40 men.
Historically, quarrying was a job done by enslaved and freed black Bermudian men. It gave them a degree of economic autonomy. While the quarry owner took 10-15% of the quarried stone, the head stonecutter kept the rest to use at his discretion. This allowed them to supplement their income by selling stone and building houses. This led a lot of black Bermudian men towards a career in stonemasonry, which, in turn, shaped the history of Bermuda’s houses. After Emancipation in 1834, Caribbean and Portuguese immigrants joined the stonemason trade.
As quarrying expanded, masons learned to read the Island’s limestone formations, each offering different strengths and levels of workability. The youngest, the Southampton Formation, provided sand for mortar, while the Rocky Bay and Belmont Formations supplied most building stone. The older Town Hill Formation became the favoured source for cut‑stone thanks to its soundness, and the ancient Walsingham Formation, though exceptionally durable, was used sparingly outside the military fortifications like those in Dockyard due to the difficulty of working it. Its density often required blasting rather than the traditional chiseling and long‑saw methods used on softer beds.
These challenges in working different types of stone set the stage for changes in quarrying technology. When quarrying began, stone-cutting technology relied on hand tools such as saws and chisels, which were used until the mid-19th century when building material such as cement clocks gained momentum as a cheaper alternative. This became the new standard for building on the Island until 1960 when British engineer, Walter Horsfield patented a stone-cutting machine capable of cutting 1700 blocks a day with a crew of only three men. Horsfield and his son later founded the Bermuda Stone Company.
In the 21st century, this job is done using two machines: the undercutter and the downcutter, which were created by Bermudian stonemason, Shawn Perrott. Perrott describes the machines as “modified lawnmowers”. The undercutter has a chainsaw attached horizontally which cuts under the limestone block, while the downcutter has a vertical chainsaw which cuts between the limestone blocks. These machines helped to revolutionise the stonecutting industry, decreasing the number of men needed to two or three.
Undercutter in Use
However, with technological progress came increased environmental concerns. In 1965, laws were enacted requiring all quarries to have the proper permits. The regulation of quarries was a blow to the communities that were financially reliant on the trade. Quarries slowly stopped operating, with most becoming privatised. Concrete blocks, which were easier to make and did not require the hassle of quarrying, became the industry standard for building structures on the Island. Today, building with limestone is considered a luxury or a fabled tale.
Though concrete is a more efficient building material, limestone’s distinctive composition is what made Bermuda homes so unique and identifiable. The island is known for its white roofs and colourfully painted limestone houses. In replacing the very building block of Bermuda, do we lose a piece of a heritage? Or do we gain more in protecting the integrity of the Island’s foundation? Whatever the correct answer, limestone has been deeply ingrained in every aspect of Bermuda for millions of years and will still be millions of years from now. So the next time you marvel at a moongate, or a Bermuda stone wall, take a moment and reflect on the importance that limestone held and continues to hold on this Island.
Learn more about Bermuda’s limestone legacy at the Museum’s exhibit STONE: From Bermuda to Charleston, featuring artist and architect John Gardner.
