[7] Bolt's Farm was heavily mined for speleothem (calcium carbonate from stalagmites, stalactites, and flowstones) in the terminal nineteenth and early twentieth centuries.
[10] The name Cradle of Humankind reflects the fact that the site has produced a substantially large number of hominin fossils, some of the oldest yet found, dating as far back as 3.5 million years ago.
In 2008, Lee Berger discovered the partial remains of two hominids (Australopithecus sediba) who lived between 1.78 and 1.95 million years ago in the Malapa Fossil Site.
In October 2013, Berger commissioned geologist Pedro Boshoff to investigate cave systems in the Cradle of Humankind for the express purpose of discovering more fossil hominin sites.
Cavers Rick Hunter and Steven Tucker discovered hominid fossils in a previously unexplored area of the Rising Star-Westminster Cave System that is assigned site designation UW-101.
In November 2013, Berger led a joint expedition of the University of the Witwatersrand and National Geographic Society to the Rising Star Cave System near Swartkrans.
In just three weeks of excavation, the six-woman international team of advance speleological scientists (K. Lindsay Eaves, Marina Elliott, Elen Feuerriegel, Alia Gurtov, Hannah Morris, and Becca Peixotto), chosen for their paleoanthropological and caving skills, as well as their small size, recovered more than 1,200 fossil specimens of an unidentified hominin species.
[16][17] In the last days of the Rising Star Expedition, cavers Rick Hunter and Steven Tucker discovered additional fossil hominid material in another portion of the cave system.
[18][19][20] The hominin remains that fossilised over time at the Cradle of Humankind are found in dolomitic caves, and are often encased in a mixture of limestone and other sediments called breccia.