Geology
Lanark County straddles two distinct geological environments:
- To the west and north, the edge of the Canadian Shield (marble, granite and gneiss predominantly);
- To the south and east, sedimentary outliers of the Saint-Lawrence Lowlands (sandstone, limestone, and shale). On top of this lies a thin veneer of glacial debris and unconsolidated post-glacial sediments.
- While every geological setting is unique, the portion of the Shield that is represented in Lanark County is part of what is known as the Central Metasedimentary Belt of Grenville Geological Province - one of the most unusual, diverse and highly studied formations in the world (although perhaps one of the least understood).
- These rocks were formed roughly one billion years ago when two continents collided to form a vast mountain range that would have rivalled today's Himalayas.
- Over the next 800 million years, the Grenville Mountains were levelled by erosion, inundated by tropical seas, scraped bare by glaciers, and flooded by the icy waters of the Atlantic.
- Perth GeoHistory Booklet
| Central to the Perth Museum's geological holdings is the historic collection of Dr. James Wilson of Perth (1798-1881). |
 Dr. Wilson was a medical doctor from Scotland who set up practice in Lanark County in 1821. He brought with him a keen interest in (and a small collection of) rocks, minerals and fossils. As he traveled between house calls in his horse-drawn buggy, he would study the local geology evident in the numerous outcrops along his route and note unusual occurrences. He became such an expert on Lanark County geology that when his Edinburgh schoolmate, William E. Logan, was engaged as the first director of the Geological Survey of Canada in 1842, Wilson was one of the first people he called upon to give him the lay of the land. This amateur/professional relationship continued for many years, resulting in several notable scientific discoveries. |
| The Perth Museum has changed location and focus over the years, but Archibald Campbell would surely be glad to know that the geological holdings he amassed are still being celebrated today. |
 As the Museum's founder and first curator, Campbell's contribution to Lanark County heritage (geological or otherwise) cannot be understated, nor can it be described any better than in his own words. In the letter below, he chronicles how the Museum came to be recognized as the best in its class in Canada, showcasing the country's ninth largest geological collection - including hundreds of his own specimens. Since his geological interests were so broad and his collection so varied, only a few of his personal items in the Matheson House display, but every piece in the room should be considered to be part of his legacy - a testament to his passion for the Earth and for Lanark County. |
| Although entirely coincidental, it is enormously serendipitous that the geological collection of Dr. Wilson should come to reside within the walls of Matheson House. |
 One notable omission in Campbell's account of the museum's beginnings is how exactly Wilson's collection came to be in his care. Roderick Matheson is generally known for being a prominent local merchant and statesman. He was also Wilson's friend and his business partner in what was likely Canada's first apatite producer. When Wilson retired to his native Scotland in 1869, he left his geological collection with Matheson for safekeeping. Years later, Roderick's son, Colonel Allan Matheson, donated the collection to the local library, which later became the first home of the Perth Museum. Campbell didn't live to see the Museum moved to Matheson House, but he would undoubtedly be delighted to know that Dr. Wilson's collection has come home. |
| Wilson & Matheson may have been the first to exploit the economic potential of the large deposits of mica and apatite in the area, but they were certainly not the last. |
 When European settlers first came to this region, they came in part for the promise land. Those who were unlucky enough to wind up with a "farm" on the Canadian Shield found their fields producing more rocks than crops. Wilson's discovery of mica and apatite potential set off a backyard industry in an area where many farmers could scant survive on their agricultural income alone. Within a few years, small pits and trenches appeared in forests and fields across the County. In 1907, William Lees McLaren started what would become one of the largest mica mines in the region. Many of the mica and apatite specimens on display in the Matheson House (and several other items as well) are from McLaren's personal collection. Just as the agricultural promise of Lanark once made way for industry, old mines have become destinations for recreational activity, festivals and tourism. The McLaren mine is now buried beneath a subdivision on, yes, McLaren Street, but the County's gritty past is still alive and well at the Silver Queen heritage mica mine in Murphy's Point Provincial Park (which is also well-represented in the museum display).There are a number of specimens in the rest of the collection from outside Lanark County. Although the Museum's current mandate is to focus on and preserve our local heritage, the scientific and historical significance of Wilson's collection is undeniable and must be maintained in its entirety. There are also many fine specimens in our collection from other parts of the Ontario's Highlands region, which is largely defined by a single geological environment - the Central Metasedimentary Belt. These specimens can be viewed as being representative of Lanark County geology, but we also hope that these pieces will serve to inspire you to follow in the footsteps of Dr. Wilson and continue to explore the untapped potential for discovery that still exists here. |
| Become a Part of "The Rock Cycle" in Perth! |
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From the geoheritage displays at Civitan Court and Matheson House, which celebrate the foundation of Lanark County and the contribution of pioneering citizen scientists like Dr. James Wilson, to the discovery location for an intriguing rock type named after the town of Perth and an underground mine tour at Murphys Point Provincial Park, the Rock Cycle loop will give you a new appreciation of Ontario's Highlands unique heritage - our Geoheritage. |
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Find out more at Perth Museum |
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Visit Perth Museum to see a sample of the collection and to learn more. |
With so many beautiful routes for touring and historic sights to see along the way, Heritage Perth has long been a favoured destination for cyclists. The Perth Chamber of Commerce has taken this a step further by producing a number of rewarding loops for you to explore, but there's one in particular that really "rocks!"