The Pierres du Niton (French for ''Neptune's Stones'') are two glacial erratics in

Lake Geneva , image = Lake Geneva by Sentinel-2.jpg , caption = Satellite image , image_bathymetry = , caption_bathymetry = , location = Switzerland, France , coords = , lake_type = Glacial la ...

, Switzerland, in

Geneva , neighboring_municipalities= Carouge, Chêne-Bougeries, Cologny, Lancy, Grand-Saconnex, Pregny-Chambésy, Vernier, Veyrier , website = https://www.geneve.ch/ Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevr ...

harbor. On the left bank of the lake near Quai Gustave-Ador, they are remnants from the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...

, left by the Rhone glacier. Because of their role in Swiss cartography, the rocks have been declared a " Geotope", a national site of geological heritage.

Geology

Genevan scientist

Horace Bénédict de Saussure Horace Bénédict de Saussure (17 February 1740 – 22 January 1799) was a Genevan geologist, meteorologist, physicist, mountaineer and Alpine explorer, often called the founder of alpinism and modern meteorology, and considered to be the firs ...

identified the rocks as

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...

from the Alps in 1779.

Jean-André Deluc Jean-André Deluc or de Luc (8 February 1727 – 7 November 1817) was a Swiss geologist, natural philosopher and meteorologist. He also devised measuring instruments. Biography Jean-André Deluc was born in Geneva. His family had come to the ...

later described the two rocks as part of a larger group of 24 erratics of similar composition: a granite with large feldspar crystals, slightly violet quartz, and slightly green chlorite. More recent analysis has determined their likely origin in the

Mont Blanc massif The Mont Blanc massif (french: Massif du Mont-Blanc; it, Massiccio del Monte Bianco) is a mountain range in the Alps, located mostly in France and Italy, but also straddling Switzerland at its northeastern end. It contains eleven major indepen ...

, being dated to around 303 million years before present. The Repère ("landmark") Pierre du Niton is the name of the rock which is bigger and further from the shore

History

The word ''Niton'' is derived from the ancient water god Neptune, who was revered by the

Gauls The Gauls ( la, Galli; grc, Γαλάται, ''Galátai'') were a group of Celtic peoples of mainland Europe in the Iron Age and the Roman period (roughly 5th century BC to 5th century AD). Their homeland was known as Gaul (''Gallia''). They s ...

who settled at the lake, as old inscriptions in Geneva and

Lausanne , neighboring_municipalities= Bottens, Bretigny-sur-Morrens, Chavannes-près-Renens, Cheseaux-sur-Lausanne, Crissier, Cugy, Écublens, Épalinges, Évian-les-Bains (FR-74), Froideville, Jouxtens-Mézery, Le Mont-sur-Lausanne, Lugrin (FR ...

indicate.Répertoire des immeubles et objets classés. Service des monuments et sites. République et Canton de Genève. Éditions Georg. Guillaume-Henri Dufour used the Repère as a height starting point by the development of the Dufour maps from 1845 to 1864 in the graduation 1:100 000. At that time the height over sea level was estimated and decreed to be 376.86 m. Up to today, this stone forms the authoritative point of the Swiss height measurement system. However, the height was newly evaluated in 1902 to be 373.6 m over sea level. This is why the data in maps of Switzerland made before 1902 differ by 3.26 m from today's official values. In the

Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...

, these stones may have had a spiritual significance and been used in religious ceremonies. This has been hypothesized due to square holes at the top of the larger stone, discovered in 1660, which seem to have been hewed by Middle Bronze Age (ca. 1500–1200 BC) axes.Arts et monuments. Ville et Canton de Genève. Armand Brulhart et Erica Deuber-Pauli. Éditions Georg.

References

{{coord, 46, 12, 20, N, 6, 09, 16, E, region:CH-GE_type:landmark_source:kolossus-dewiki, display=title Geography of Geneva Glacial erratics in Switzerland Zero-level elevation points