The Machupicchu Historic National Sanctuary is found over a great granite orogenic structure baptized by Dr. Isaiah Bowman as the " Vilcapampa Batholith" that outcrops over about 400 km² (154 mile²). Its formation belongs in the scale of geological time to the Paleozoic or Inferior Primary and may have an approximate age of 250 million years. The Vilcapampa Batholith's white-gray granite is an intrusive igneous rock (magma cooled off in great profundities inside the earth); it is mainly compound in average by 60% of feldspar, 30% of quartz, and a 10% of mica. That granite has interlaced equigranular texture and possesses from 6° to 7° of hardness in the MOHS scale with a resistance of 1200 Kg/cm². Likewise, in this region there are some other rocks corresponding to the Inferior Paleozoic; such as schist, quartzite and metamorphic conglomerations that might have an age from 350 to 450 million years. Machupicchu (like most of the Quechua names of towns and different sites in the region) is a compound word that comes from machu = old or ancient, and picchu = peak or mountain; therefore, Machupicchu is translated as "Old Mountain". The famous mountain that is seen in front, and appears in most of the classical views of the site is named Waynapicchu (Young Mountain). Unfortunately the original names of the mentioned sectors are lost, Machupicchu, Waynapicchu and some other proper names used today are contemporary ones; ascribed probably by farmers living in the region before Bingham's arrival. However, according to studies about some XVI century documents, the original name of the whole area might be "Picchu".