Table Mountain rises above Cape Town as a broad horizontal platform bordered by cliffs. Its highest point reaches about 1,086 meters, while the conspicuous northern plateau extends roughly three kilometers from side to side. The summit appears almost engineered, yet no single event sliced the mountain flat. Its shape is the surviving intersection of nearly level sandstone layers, ancient folding, and prolonged differential erosion.
Flat does not mean perfectly even. Bedding surfaces, shallow depressions, drainage channels, and resistant ledges give the summit subdued relief, and its eastern high point stands above the area near the upper cable station. From a distance, however, these variations are small compared with the surrounding cliffs, so the skyline reads as a single level table.
The pale upper cliffs are composed mainly of the Peninsula Formation, historically called Table Mountain Sandstone. This unit belongs to the Table Mountain Group and consists of thick beds of quartz-rich sandstone deposited early in the Paleozoic Era. Burial compacted and cemented the original sand, producing exceptionally hard quartzitic rock that now forms much of the mountain’s upper 600 to 700 meters.
The Plateau Began as Layered Sediment
The Cape Peninsula exposes three broad rock packages. Metamorphosed mudstones and sandstones of the Malmesbury Group are among the oldest. Coarse Cape Granite intruded them about 540 million years ago and now underlies many lower slopes. Above an erosional boundary sits the younger Table Mountain Group, beginning with reddish sandstone and mudstone of the Graafwater Formation and continuing upward into the massive, light-colored Peninsula Formation.
The beds forming the main plateau were deposited broadly horizontally as sand. They were later affected by the compression that created the Cape Fold Belt. In many neighboring ranges, the same rock sequence was tilted into prominent folds. Around Table Mountain, the surviving strata occupy a broad synclinal structure in which layers near the center remain comparatively level.
This creates a reversal of what might be expected from the original fold. A syncline is a downfold, so its center initially occupies a lower structural position than an adjoining anticline. Over immense spans of erosion, however, elevation depends less on the original fold crest than on which rocks withstand removal. Formerly higher folded ground east of the mountain was stripped away, while resistant sandstone in the syncline survived as high terrain.
Resistance Preserved the Table
Quartz dominates the Peninsula Formation and is comparatively resistant to chemical weathering. Strong cement and thick bedding allow it to maintain steep cliffs where less durable material has receded. Softer mud-rich layers and deeply weathered granite are more readily broken down and carried away, helping produce gentler lower slopes and the broad Cape Flats beyond the massif.
The summit should not be pictured as a thin sandstone lid placed over an otherwise unrelated mountain. The resistant formation constitutes a substantial part of the mountain itself. Its nearly horizontal bedding presents broad rock surfaces at similar elevations, while erosion trims their exposed edges backward. The result resembles a cap because the cliff-forming upper unit stands above more easily weathered rocks below.
Some higher layers once continued above the present surface. Remnants of the Pakhuis Formation, containing debris deposited during an ancient glaciation, occur near the top in places. Their limited preservation shows that the modern plateau is an erosional remainder, not the untouched upper surface of the original sedimentary sequence.
Joints Cut the Cliffs Into Blocks
Even resistant sandstone contains fractures. Vertical joints divide the pale cliffs into large columns and slabs, giving the walls their squared appearance. Water enters these openings, chemical alteration weakens mineral contacts, and temperature changes assist physical breakdown. Gravity eventually removes loosened blocks, causing the cliff line to retreat.
Gorges exploit the same weaknesses. Platteklip Gorge cuts deeply into the front of the mountain where runoff and rockfall have enlarged a structural pathway. Other ravines separate buttresses around the plateau and the Back Table. Erosion therefore preserves the overall horizontal cap while steadily dissecting its margins.
Table Mountain’s profile is durable but not permanent. The flatness comes from the orientation and strength of its sandstone, whereas the abrupt sides record the loss of neighboring rock. Each cliff collapse narrows the plateau slightly. What remains is a temporary stage in a much longer transformation from layered sediment, to folded rock mass, to isolated sandstone table.