Rock of Gibraltar

The Rock of Gibraltar (from the Arabic name Jabel-al-Tariq) is a monolithic limestone promontory located in the British territory of Gibraltar, near the southwestern tip of Europe on the Iberian Peninsula, and near the entrance to the Mediterranean. It is high. Most of the Rock's upper area is covered by a nature reserve, which is home to around 300 Barbary macaques. These macaques, as well as a labyrinthine network of tunnels, attract many tourists each year. The Rock of Gibraltar, one of the two traditional Pillars of Hercules, was known to the Romans as Mons Calpe, the other pillar being Mons Abila, either Monte Hacho or Jebel Musa on the African side of the Strait. According to ancient myths fostered by the Greeks and the Phoenicians, and later perpetuated by the Romans, the two points marked the limit to the known world, although the Phoenicians had actually sailed beyond this point into the Atlantic, both northward and southward. The Mediterranean Sea surrounds Gibraltar. The Rock of Gibraltar is a monolithic promontory. The Main Ridge has a sharp crest with peaks over 400 m above sea level, formed by Early Jurassic limestones and dolomites. It is a deeply eroded and highly faulted limb of an overturned fold. The sedimentary strata composing the Rock of Gibraltar are overturned, with the oldest strata overlying the youngest strata. These strata are the Catalan Bay Shale Formation (youngest), Gibraltar Limestone, Little Bay Shale Formation (oldest), and Dockyard Shale Formation (age unknown). These strata are noticeably faulted and deformed. Predominantly of shale, the Catalan Bay Shale Formation also contains thick units composed of either brown calcareous sandstone, soft shaly sandstone interbedded with bluish-black limestone, and interlayered greenish-gray marls and dark gray cherts. The Catalan Bay Shale Formation contains unidentifiable echinoid spines and belemnite fragments and infrequent Early Jurassic (Middle Lias) ammonites.