Rocks (Klipriversberg)

Some rocks from the Klipriversberg, the view of the city skyline and the sewerage pipe that runs through the reserve.

"The lava forming the hills is not uniform but consists of many kinds of volcanic rock. These are ordinary lava flows and are often marked by white inclusions (like pebbles) at the top. They are called Amygdales, and were bubbles caused by the release of gasses in the molten rock which froze into position and were later filled with silica (quartz). Tuffs made up of volcanic ash, fossilised pumice and agglomerates of volcanic cinders can also be seen. At a point near the sewer pipe Collumnar basalts can be seen where the cooling lava shrank to form columns. In places angular crystals in the lava, called Phenocrysts are also visible. These indicate that the lava was cooling and crystallising before reaching the surface" http://www.klipriviersberg.org.za/index.php/geology