Geology of the Uniondale area
Last Updated: March 2017
About Geology of the Uniondale area
Whether you are approaching Uniondale on the N9 from George or from Willowmore you can’t help but notice the flat-top hills, or ‘mesas’, as they are technically termed. The locals call these distinctive features ‘die oervlakte’.
The tops of the hills are the remnants of the vast plain of the ancient ‘African Surface’, formed over 460 million years ago when Africa was part of the super-continent called ‘Gondwana’.
The surfaces of these mesas are covered with colourful small pebbles, shaped by time and weather over millions of years to a fairly uniform size. Although delightful for landscape gardening, please be aware that the hills are on private property . It’s also environmentally insensitive (and illegal ) to fill your pockets with these stones!
Another geological wonder to be found in the area, is the delightful 11km Uniondale Poort, which takes one through to Avontuur, Haarlem and the Langkloof.
The original route for bringing timber through to Uniondale from Knysna – die Wapad – was probably built by Thomas Bain as an extension to Prince Alfred’s Pass. As it became impossible to traverse by motorised vehicles, the Uniondale Poort was built circa 1925.
As you drive through the Poort, enjoy the chance to look closely at the Table Mountain sandstone strata so distinctive of the area, twisted sometimes vertically into strange formations, with cliff faces supporting aloes and wild pelargoniums. In the evening light these rock faces positively glow.
Other geological features are the shales and muddy sandstones of the Bokkeveld Group, originally laid down in ancient seas millions of years ago and to be seen on Stoneleigh Golf Course and on many hillsides. The slabs of slate have been put to good use by farmers for building walls and ‘kraals’ for livestock.
Last but not least, we have the spectacular Kammanassie Mountain range, which is an ‘insulberg’ or free-standing series of mountains. The Kammanassie River runs down the valley from Uniondale and irrigates the many farms in the area, which produce unusual fruits for export, like Mediterranean figs and pomegranates, as well as apricots, plums and pears. Seed growing is also a successful crop.