The Tombstone Mountains are in fact a distinct range within the Southern Ogilvie Mountains. They are famous for their stunning topography, jagged ridges and immense vertical faces of imposing rock, some more than 2000 feet high: hence the name “Tombstones”. Its geological history is quite interesting. The Tombstones were not thrust up from the earth due to plate tectonics, as many mountains are, but rather the story of the Tombstones is a darker affair, having its beginning deep in the earth’s crust. Here hot molten-lava surged into cracks in the earth’s crust and then slowly cooled, creating a fine-grained and quite hard rock known as syenite. As time passed the softer sedimentary rock in which the Tombstones cooled, the “overburden” as it’s called, eroded away to slowly reveal the Tombstones, which due to their hardness were better able to resist erosion. The Tombstone Mountains are situated right at the edge of Beringia, a zone of Alaska and the Yukon that remained ice-free during the periods of glaciation. This ice-free zone was caused by the rain-shadow effect of the tall Costal Mountains of the pacific-northwest. The Tombstones, however, did not escape the ice. The immense sheets of ice scoured the land creating u-shaped valley bottoms and such distinct features as arêtes: thin razor-like ridges formed by the erosive force of parallel valley glaciers. Modern-day access to the park was made possible by the construction of the Dempster Highway, which was begun in 1959 but not fully completed until 1979. The highway is named after Inspector William Dempster of the Royal Northwest Mounted Police, who headed the search for the infamous Lost Patrol. The Dempster Highway is Canada’s northernmost highway, stretching 671 km (417 miles) to the town of Inuvik, Northwest Territories. It is an engineering triumph. Designers had to pioneer new techniques for building on permafrost, such as laying down a gravel pad 1.5- -2.5m (4-8 feet ) in thickness to insulate the permafrost below from the heat of the short, but sometimes intense, summer. Without this thick layer of insulating gravel the highway would literally sink into the ground. The highway is famous for its stunning fall colours, unsurpassed wilderness, and amazing opportunities to view wildlife.