time a collision of tectonic plates caused huge sheets of sedimentary rock in what is now British Columbia to become detached and slide eastward to northeastward over their neighbors, piling up to form the southern Canadian Rockies. This left the Paleozoic strata on Mount Rundle dipping steeply to the southwest, so that the southwest-facing side of the mountain forms an extensive dip slope. Geologists consider Mount Rundle to be a classic example of a mountain cut in dipping layered rocks, with the tilted strata giving the mountain its shape. The most recent stage in the history of Mount Rundle began in the Pleistocene epoch about 2 million years ago with the sculpting and gouging of the Canadian Rockies by glaciers, and then by streams and rivers. Finally, after the glaciers retreated for the last time, a series of steep, tree-covered alluvial fans began to grow at the mouths of the deep gulches on the northeast-facing side of the mountain. Commerce Rundle rock or Rundle stone, a natural stone, first quarried on Mount Rundle, is a common dimension stone used in southern Alberta for landscaping and building purposes. It has been used in the construction of the Banff Springs Hotel and several of the Parks Canada buildings. It is fine-grained sandstone dating back to the Triassic Period. Scrambles At the EEOR near Canmore there is a well-known scramble, the Goat Creek hiking trail, with its starting point at parking trailhead, which starts at the Smith-Dorrien/Spray Trail just south of the Canmore Reservoir above Grassi Lakes. This is also the beginning of the Mount Rundle Traverse, a demanding trek to mount all of Rundle's peaks from Goat Creek parking lot to the Banff Springs Hotel. Mount Rundle is one of the most popular scrambles in the area, and is relatively straightforward for experienced hikers. In Banff, the Spray River trailhead for the first peak taking the Mount Rundle Trail, is near the Spray River bridge on the road to the Banff Springs Golf Course. The all-day hike (from 8–10 hours) from the trailhead to the peak is about one-way and has an elevation gain of about to the cliff bank on the first peak and to the summit. Although it is called non-technical, it is considered gruelling by some. About halfway up there is a Central Gully, a huge watercourse with a well-worn path which is a dead end. Cliffs become higher