{"id":3189,"date":"2024-10-24T19:00:21","date_gmt":"2024-10-24T18:00:21","guid":{"rendered":"https:\/\/edinburghname.com\/?p=3189"},"modified":"2025-07-02T12:56:22","modified_gmt":"2025-07-02T11:56:22","slug":"the-rocks-beneath-edinburghs-cobbles","status":"publish","type":"post","link":"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles","title":{"rendered":"The Rocks Beneath Edinburgh&#8217;s Cobbles"},"content":{"rendered":"\n<p>Edinburgh is world-renowned for its unique beauty and stunning landscapes. But fewer people are aware of the city&#8217;s fascinating topography, which owes its existence to a diverse range of underlying rocks. The city&#8217;s modern landscape was sculpted by geological erosion, a process especially pronounced during the Pleistocene epoch. Often referred to as the Ice Age, this period began roughly 2.6 million years ago. Find out more at\u00a0<a href=\"https:\/\/edinburghname.com\/en\">edinburghname<\/a>.<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_74 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<label for=\"ez-toc-cssicon-toggle-item-6a4b21abdd9a5\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-6a4b21abdd9a5\"  aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles\/#Edinburghs_Foundational_Rocks\" >Edinburgh&#8217;s Foundational Rocks<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles\/#A_Tale_of_Hard_and_Soft_Rock\" >A Tale of Hard and Soft Rock<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles\/#A_Tropical_Past_Edinburghs_Sedimentary_Story\" >A Tropical Past: Edinburgh&#8217;s Sedimentary Story<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles\/#Echoes_of_a_Lost_Ocean\" >Echoes of a Lost Ocean<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles\/#Edinburghs_Volcanic_Heart\" >Edinburgh&#8217;s Volcanic Heart<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles\/#The_Legacy_of_Smaller_Volcanoes\" >The Legacy of Smaller Volcanoes<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/edinburghname.com\/en\/eternal-3189-the-rocks-beneath-edinburghs-cobbles\/#Magma_Beneath_the_Surface\" >Magma Beneath the Surface<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Edinburghs_Foundational_Rocks\"><\/span>Edinburgh&#8217;s Foundational Rocks<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1600\" height=\"1050\" src=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2.png\" alt=\"\" class=\"wp-image-3190\" srcset=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2.png 1600w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-300x197.png 300w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-768x504.png 768w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-1536x1008.png 1536w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-696x457.png 696w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-1068x701.png 1068w\" sizes=\"auto, (max-width: 1600px) 100vw, 1600px\" \/><\/figure>\n\n\n\n<p>For over 10,000 years, humans have harnessed Edinburgh&#8217;s unique geology and landscape. The terrain has been strategically used for settlements, agriculture, defence, and, naturally, for construction. The Edinburgh area is characterised by two main types of rock: <strong>sedimentary and igneous<\/strong>. Sedimentary rocks were formed from the slow build-up of deposits in shallow seas and river systems. Igneous rocks, on the other hand, were created when volcanic lava cooled on the Earth&#8217;s surface or when magma solidified within the crust.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"A_Tale_of_Hard_and_Soft_Rock\"><\/span>A Tale of Hard and Soft Rock<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>A <strong>key distinction between sedimentary and igneous rocks is their hardness<\/strong>. Igneous rock is generally harder and erodes far more slowly. It&#8217;s for this reason that these rocks form the area&#8217;s hills, most notably <strong>The Pentland Hills and the Seven Hills of Edinburgh<\/strong>. In contrast, sedimentary rock is much softer and wears away more easily, resulting in a gently rolling landscape.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"A_Tropical_Past_Edinburghs_Sedimentary_Story\"><\/span>A Tropical Past: Edinburgh&#8217;s Sedimentary Story<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2.png\" alt=\"\" class=\"wp-image-3193\" srcset=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2.png 1024w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-300x197.png 300w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-768x504.png 768w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-2-696x457.png 696w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Around 350 million years ago, the land that is now Edinburgh was part of a large continent with a warm, humid climate. Erosion wore down mountains to the north, washing sediment into vast river systems that flowed southwards. Over time, the environment transformed cyclically, primarily due to fluctuating sea levels. Geologists point to locations like <strong>Barn\u2019s Ness in East Lothian and the Water of Leith in Stockbridge<\/strong> as clear examples of these changes.<\/p>\n\n\n\n<p>River deltas and lush swamps also played a significant role. River channels collected sand, which over time compacted into the layers of <strong>sandstone that would become a key building material for Edinburgh<\/strong>. In other areas, dense swamp vegetation accumulated and eventually formed coal. At times, the sea level rose dramatically, flooding the central lowlands with warm waters. These seas teemed with life, including corals, brachiopods, and crinoids (sea lilies), whose remains formed the layers of <strong>limestone<\/strong> found in places like East Lothian.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Echoes_of_a_Lost_Ocean\"><\/span>Echoes of a Lost Ocean<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"769\" src=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-3.png\" alt=\"\" class=\"wp-image-3196\" srcset=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-3.png 1024w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-3-300x225.png 300w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-3-768x577.png 768w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-3-696x523.png 696w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Even older sedimentary rocks can be found in the Edinburgh area, remnants of the deep Iapetus Ocean that once lay south of Scotland. This ocean vanished around 420 million years ago when tectonic plate movements brought continents together. The collision folded and buckled the ancient seabed, transforming its deposits into the contorted layers of mudstone and sandstone now visible at locations like <strong>Siccar Point and The Pentland Hills<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Edinburghs_Volcanic_Heart\"><\/span>Edinburgh&#8217;s Volcanic Heart<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>The igneous rocks in the Edinburgh region are the product of intense volcanic activity. The durable igneous rock that forms <strong>The Pentland Hills<\/strong>, south of the city, is over 400 million years old. The magma that erupted to the surface had a varied chemical makeup, leading to the formation of several different rock types, including <strong>rhyolite, basalt, trachyte, and andesite<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"The_Legacy_of_Smaller_Volcanoes\"><\/span>The Legacy of Smaller Volcanoes<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>After a 70-million-year lull, volcanic activity returned to the Edinburgh area. This time, it involved smaller, short-lived volcanoes, mostly basaltic in nature. As these eruptions occurred on a wet landscape, the interaction between hot magma and water caused violent explosions, scattering bombs of lava and volcanic ash across the area. The hilly landscape of central Edinburgh is formed from the remnants of these very volcanoes. Notable examples include <strong>Calton Hill, Arthur\u2019s Seat, and Craiglockhart Hill<\/strong>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Magma_Beneath_the_Surface\"><\/span>Magma Beneath the Surface<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1080\" height=\"1350\" src=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-4.png\" alt=\"\" class=\"wp-image-3199\" srcset=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-4.png 1080w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-4-240x300.png 240w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-4-768x960.png 768w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-4-696x870.png 696w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-4-1068x1335.png 1068w\" sizes=\"auto, (max-width: 1080px) 100vw, 1080px\" \/><\/figure>\n\n\n\n<p>Not all magma reached the surface. Some was trapped underground, where it squeezed between existing layers of sedimentary rock. This created flat, horizontal sheets of a hard, crystalline rock called <strong>dolerite<\/strong>, known as sills. Dolerite was famously quarried at Salisbury Crags. Thanks to its exceptional durability, it was widely used to make <strong>setts for paving Edinburgh\u2019s historic streets<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"512\" height=\"341\" src=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-5.png\" alt=\"\" class=\"wp-image-3202\" srcset=\"https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-5.png 512w, https:\/\/cdn.edinburghname.com\/wp-content\/uploads\/sites\/60\/2025\/07\/image-5-300x200.png 300w\" sizes=\"auto, (max-width: 512px) 100vw, 512px\" \/><\/figure>\n\n\n\n<p>Edinburgh&#8217;s geological heritage is truly one of its greatest assets. These ancient rocks not only provided the foundations and materials for the city&#8217;s growth but also offer a fascinating window into the deep past of Scotland&#8217;s picturesque capital.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Edinburgh is world-renowned for its unique beauty and stunning landscapes. But fewer people are aware of the city&#8217;s fascinating topography, which owes its existence to a diverse range of underlying rocks. The city&#8217;s modern landscape was sculpted by geological erosion, a process especially pronounced during the Pleistocene epoch. Often referred to as the Ice Age, [&hellip;]<\/p>\n","protected":false},"author":456,"featured_media":2334,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[338],"tags":[1881,1882,1892,1883,1893,1885,1889,1886,1884,1887,1546,1880,1891,1890,1888],"moimportance":[],"motype":[325],"moformat":[],"class_list":{"0":"post-3189","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-developments","8":"tag-arthurs-seat-volcano","9":"tag-building-with-sandstone","10":"tag-dolerite-paving-setts","11":"tag-edinburgh-geology","12":"tag-edinburgh-landscape-formation","13":"tag-edinburgh-volcanic-history","14":"tag-edinburghs-seven-hills","15":"tag-geology-of-edinburgh","16":"tag-iapetus-ocean-scotland","17":"tag-igneous-rock-scotland","18":"tag-pentland-hills","19":"tag-salisbury-crags","20":"tag-scottish-geology","21":"tag-sedimentary-rock-edinburgh","22":"tag-siccar-point","23":"motype-eternal"},"_links":{"self":[{"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/posts\/3189","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/users\/456"}],"replies":[{"embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/comments?post=3189"}],"version-history":[{"count":1,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/posts\/3189\/revisions"}],"predecessor-version":[{"id":3205,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/posts\/3189\/revisions\/3205"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/media\/2334"}],"wp:attachment":[{"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/media?parent=3189"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/categories?post=3189"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/tags?post=3189"},{"taxonomy":"moimportance","embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/moimportance?post=3189"},{"taxonomy":"motype","embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/motype?post=3189"},{"taxonomy":"moformat","embeddable":true,"href":"https:\/\/edinburghname.com\/en\/wp-json\/wp\/v2\/moformat?post=3189"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}