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31-542: In 1824, Lanark County was created from part of Carleton County, so that its constituent townships were divided as follows: together with such Islands in the Ottawa River as are wholly or in greater part opposite thereto together with all the unsurveyed lands within the District of Bathurst, and such Islands in the Ottawa River as are wholly or in greater part opposite to the said townships and unsurveyed land In 1838, upon

62-521: A gneiss is a coarse-grained metamorphic rock showing compositional banding ( gneissic banding ) but poorly developed schistosity and indistinct cleavage . In other words, it is a metamorphic rock composed of mineral grains easily seen with the unaided eye, which form obvious compositional layers, but which has only a weak tendency to fracture along these layers. In Europe, the term has been more widely applied to any coarse, mica -poor, high-grade metamorphic rock. The British Geological Survey (BGS) and

93-631: A population density of 25.4/km (65.7/sq mi) in 2021. The county is one of the top centres of maple syrup production in Ontario and describes itself as "The Maple Syrup Capital of Ontario". There are two provincial parks in Lanark County: Murphy's Point Provincial Park on Big Rideau Lake and Silver Lake Provincial Park along Highway 7 near the west end of the county. The Rideau Trail and Trans-Canada Trail both go through Lanark County. There are also several conservation areas run by

124-459: A rare fern, blunt-lobed woodsia . Cliff Bennett provides a list of 26 routes for canoe and kayak exploration of the county. From the census division in the 2021 Census of Population conducted by Statistics Canada , Lanark County had a population of 75,760 living in 31,909 of its 35,441 total private dwellings, a change of 10.3% from its 2016 population of 68,698 . With a land area of 2,986.71 km (1,153.18 sq mi), it had

155-575: Is a stub . You can help Misplaced Pages by expanding it . Lanark County, Ontario Lanark County is a county and census division located in the Canadian province of Ontario . Its county seat is Perth , which was first settled in 1816 and was known as a social and political capital before being over shadowed by what we now know as Ottawa . Most European settlements of the county began in 1816, when Drummond, Beckwith and Bathurst townships were named and initially surveyed. The first farm north of

186-475: Is a gneiss resulting from metamorphism of granite, which contains characteristic elliptic or lenticular shear-bound grains ( porphyroclasts ), normally feldspar , surrounded by finer grained material. The finer grained material deforms around the more resistant feldspar grains to produce this texture. Migmatite is a gneiss consisting of two or more distinct rock types, one of which has the appearance of an ordinary gneiss (the mesosome ), and another of which has

217-518: Is called gneissic banding. The darker bands have relatively more mafic minerals (those containing more magnesium and iron ). The lighter bands contain relatively more felsic minerals (minerals such as feldspar or quartz , which contain more of the lighter elements, such as aluminium , sodium , and potassium ). The banding is developed at high temperature when the rock is more strongly compressed in one direction than in other directions ( nonhydrostatic stress ). The bands develop perpendicular to

248-449: Is classified as schist, while metamorphic rock devoid of schistosity is called a granofels . Gneisses that are metamorphosed igneous rocks or their equivalent are termed granite gneisses, diorite gneisses, and so forth. Gneiss rocks may also be named after a characteristic component such as garnet gneiss, biotite gneiss, albite gneiss, and so forth. Orthogneiss designates a gneiss derived from an igneous rock , and paragneiss

279-516: Is formed under pressures anywhere from 2 to 15 kbar, sometimes even more, and temperatures over 300 °C (572 °F). Gneiss nearly always shows a banded texture characterized by alternating darker and lighter colored bands and without a distinct cleavage . Gneisses are common in the ancient crust of continental shields . Some of the oldest rocks on Earth are gneisses, such as the Acasta Gneiss . In traditional English and North American usage,

310-510: Is one from a sedimentary rock . Both the BGS and the IUGS use gneissose to describe rocks with the texture of gneiss, though gneissic also remains in common use. For example, a gneissose metagranite or a gneissic metagranite both mean a granite that has been metamorphosed and thereby acquired gneissose texture. The minerals in gneiss are arranged into layers that appear as bands in cross section. This

341-506: Is subjected to extreme temperature and pressure and is composed of alternating layers of sandstone (lighter) and shale (darker), which is metamorphosed into bands of quartzite and mica. Another cause of banding is "metamorphic differentiation", which separates different materials into different layers through chemical reactions, a process not fully understood. Augen gneiss , from the German : Augen [ˈaʊɡən] , meaning "eyes",

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372-710: The International Union of Geological Sciences (IUGS) both use gneiss as a broad textural category for medium- to coarse-grained metamorphic rock that shows poorly developed schistosity, with compositional layering over 5 millimeters (0.20 in) thick and tending to split into plates over 1 centimeter (0.39 in) thick. Neither definition depends on composition or origin, though rocks poor in platy minerals are more likely to produce gneissose texture. Gneissose rocks thus are largely recrystallized but do not carry large quantities of micas, chlorite or other platy minerals. Metamorphic rock showing stronger schistosity

403-719: The Mississippi Valley Conservation Authority , the Rideau Valley Conservation Authority , and the Mississippi Madawaska Land Trust. The K&P rail trail goes through the northwest corner of the county. Gneiss Gneiss ( / n aɪ s / nice ) is a common and widely distributed type of metamorphic rock . It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks . This rock

434-634: The Carleton Place Hackberry stand. Also of interest is an old shoreline which crosses the county diagonally, approximately from Almonte in the northeast to Perth in the southwest. This shoreline was formed about 12,000 years ago near the end of the last ice age when much of the Ottawa Valley was inundated by the Champlain Sea . Many areas below this old shoreline are flat clay plains, with occasional outcrops of gneiss or limestone ridges. Some of

465-558: The Rideau was cleared and settled somewhat earlier, in 1790. The county took its name from the town of Lanark in Scotland . Nearly all the townships were named after British public and military figures from the era of early settlement. In 1824, Lanark County was severed from Carleton County in Bathurst District , and it consisted of the following townships and lands: together with all

496-453: The amphibolite or granulite facies. These form most of the exposed rock in Archean cratons . Gneiss domes are common in orogenic belts (regions of mountain formation). They consist of a dome of gneiss intruded by younger granite and migmatite and mantled with sedimentary rock. These have been interpreted as a geologic record of two distinct mountain-forming events, with the first producing

527-538: The appearance of an intrusive rock such pegmatite , aplite , or granite the ( leucosome ). The rock may also contain a melanosome of mafic rock complementary to the leucosome. Migmatites are often interpreted as rock that has been partially melted, with the leucosome representing the silica-rich melt, the melanosome the residual solid rock left after partial melting, and the mesosome the original rock that has not yet experienced partial melting. Gneisses are characteristic of areas of regional metamorphism that reaches

558-466: The area was potash , made from the ashes of the trees burned in clearing. The natural diversity of the landscape supports over 1,200 species of plants in the county flora. Seventeen areas have been documented as outstanding examples of plant diversity; these include Blueberry Mountain, Burnt Lands Alvar, Clay Bank Alvar, Christie Lake, Murphy's Point Provincial Park and Almonte Town Park. The county also has 47 provincially significant wetlands. Some of

589-416: The bottom of the deck in the other direction. These forces stretch out the rock like a plastic , and the original material is spread out into sheets. Per the polar decomposition theorem , the deformation produced by such shearing force is equivalent to rotation of the rock combined with shortening in one direction and extension in another. Some banding is formed from original rock material (protolith) that

620-660: The creation of a Provisional Municipal Council that held its first meeting in June 1861. The United Counties were dissolved in August 1866. Smiths Falls is a separated town and is for municipal purposes not part of the county. It is mostly located in Lanark, while its southern part was annexed from the United Counties of Leeds and Grenville . The county is located in the sub-region of Southern Ontario named Eastern Ontario . Geologically,

651-523: The creation of the Dalhousie District , the townships were reorganized as follows: By 1845, all lands in the District had been surveyed into the following townships: Effective January 1, 1850, Bathurst District was abolished, and the United Counties of Lanark and Renfrew replaced it for municipal and judicial purposes. 45°15′N 76°30′W  /  45.25°N 76.5°W  / 45.25; -76.5 This Ontario location article

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682-402: The direction of greatest compression, also called the shortening direction, as platy minerals are rotated or recrystallized into parallel layers. A common cause of nonhydrodynamic stress is the subjection of the protolith (the original rock material that undergoes metamorphism) to extreme shearing force, a sliding force similar to the pushing of the top of a deck of cards in one direction, and

713-501: The distinctive southern animals in the county include five-lined skinks (Ontario's only species of lizard), black ratsnakes and southern flying squirrels . Unusual southern plants include arrow arum , a nationally rare wetland plant found near Mississippi Lake. The south-facing cliffs over Big Rideau Lake , including Foley Mountain , have a slightly warmer climate, and therefore support an unusual southern flora including shagbark hickory , tall cinquefoil ( Potentilla arguta ) and

744-582: The granite basement and the second deforming and melting this basement to produce the domes. However, some gneiss domes may actually be the cores of metamorphic core complexes , regions of the deep crust brought to the surface and exposed during extension of the Earth's crust . The word gneiss has been used in English since at least 1757. It is borrowed from the German word Gneis , formerly also spelled Gneiss , which

775-700: The largest are Blueberry Marsh (north of Perth), the Innisville Wetlands (upstream of Mississippi Lake) and the Goodwood Marsh south of Carleton Place. In addition to David White's list of 17 areas of plant diversity, Paul Keddy lists 17 special places in the county. Both lists have the Burnt Lands Alvar, the Christie Lake Barrens and Murphy's Point Provincial Park . Keddy's list adds areas such as Playfairville Rapids, Lavant/Darling Spillway and

806-418: The last ice age. At the time of settlement, most of the county was covered in temperate deciduous forest; the dominant forest trees included maple , hemlock , oak and beech . Some of the higher ridges in the west of the county were likely once natural fire barrens, with a distinctive fauna and flora. The clearance of forests began with early settlement, at which time one of the important exports from

837-521: The middle amphibolite to granulite metamorphic facies . In other words, the rock was metamorphosed at a temperature in excess of 600 °C (1,112 °F) at pressures between about 2 to 24 kbar . Many different varieties of rock can be metamorphosed to gneiss, so geologists are careful to add descriptions of the color and mineral composition to the name of any gneiss, such as garnet-biotite paragneiss or grayish-pink orthogneiss . Continental shields are regions of exposed ancient rock that make up

868-644: The northern part of the county is in the Canadian Shield and the southern part is in the Great Lakes Basin . The county has two large rivers, the Mississippi and Rideau , each of which empty into the Ottawa River . The landscape is varied including Canadian Shield (with gneiss , granite and marble ) as well as limestone plains, with a variety of tills, sands and clays left from the melting of glaciers in

899-596: The stable cores of continents. The rock exposed in the oldest regions of shields, which is of Archean age (over 2500 million years old), mostly belong to granite-greenstone belts. The greenstone belts contain metavolcanic and metasedimentary rock that has undergone a relatively mild grade of metamorphism, at temperatures of 350–500 °C (662–932 °F) and pressures of 200–500 MPa (2,000–5,000 bar). The greenstone belts are surrounded by high-grade gneiss terrains showing highly deformed low-pressure, high-temperature (over 500 °C (932 °F)) metamorphism to

930-618: The township of Pakenham was transferred from Renfrew to Lanark. Effective January 1, 1850, Bathurst District was abolished, and the "United Counties of Lanark and Renfrew" replaced it for municipal and judicial purposes. The counties remained united for electoral purposes in the Parliament of the Province of Canada , referred to as the County of Lanark, until Renfrew gained its own seat in 1853. The separation of Renfrew from Lanark began in 1861, with

961-431: The unsurveyed lands within the District of Bathurst, and such Islands in the Ottawa River as are wholly or in greater part opposite to the said townships and unsurveyed land When Carleton was withdrawn from the District in 1838, Renfrew County was severed from part of Lanark, but the two remained united for electoral purposes. By 1845, all lands in the District had been surveyed into the following townships: In 1851,

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