section_path: Scholarly achievements/Geology
section_name: Geology
paragraph_text: Geology
  
  The ancient Greek Aristotle (384 BC–322 BC) wrote in his Meteorology of how the earth had the potential for physical change, including the belief that all rivers and seas at one time did not exist where they were, and were dry. The Greek writer Xenophanes (570 BC–480 BC) wrote of how inland marine fossils were evidence that massive periodic flooding had wiped out mankind several times in the past, but never wrote of land formation or shifting seashores. Du Yu (222–285) a Chinese Jin dynasty officer, believed that the land of hills would eventually be leveled into valleys and valleys would gradually rise to form hills. The Daoist alchemist Ge Hong (284–364) wrote of the legendary immortal Magu; in a written dialogue by Ge, Ma Gu described how what was once the Eastern Sea (i.e. East China Sea) had transformed into solid land where mulberry trees grew, and would one day be filled with mountains and dry, dusty lands. The later Persian Muslim scholar Abū Rayhān al-Bīrūnī (973–1048) hypothesized that India was once covered by the Indian Ocean while observing rock formations at the mouths of rivers.
  
  It was Shen Kuo who formulated a hypothesis about the process of land formation (geomorphology) based upon several observations as evidence. This included his observation of fossil shells in a geological stratum of a mountain hundreds of miles from the ocean. He inferred that the land was reshaped and formed by erosion of the mountains, uplift, and the deposition of silt, after observing strange natural erosions of the Taihang Mountains and the Yandang Mountain near Wenzhou. He hypothesized that, with the inundation of silt, the land of the continent must have been formed over an enormous span of time. While visiting the Taihang Mountains in 1074, Shen Kuo noticed strata of bivalve shells and ovoid rocks in a horizontal-running span through a cliff like a large belt. Shen proposed that the cliff was once the location of an ancient seashore that by his time had shifted hundreds of miles east. Shen wrote that in the Zhiping reign period (1064–1067) a man of Zezhou unearthed an object in his garden that looked like a serpent or dragon, and after examining it, concluded the dead animal had apparently turned to "stone". The magistrate of Jincheng, Zheng Boshun, examined the creature as well, and noted the same scale-like markings that were seen on other marine animals. Shen Kuo likened this to the "stone crabs" found in China.
  
  Shen also wrote that since petrified bamboos were found underground in a climatic area where they had never been known to be grown, the climate there must have shifted geographically over time. Around the year 1080, Shen Kuo noted that a landslide on the bank of a large river near Yanzhou (modern Yan'an) had revealed an open space several dozens of feet under the ground once the bank collapsed. This underground space contained hundreds of petrified bamboos still intact with roots and trunks, "all turned to stone" as Shen Kuo wrote. Shen Kuo noted that bamboos do not grow in Yanzhou, located in northern China, and he was puzzled during which previous dynasty the bamboos could have grown. Considering that damp and gloomy low places provide suitable conditions for the growth of bamboo, Shen deduced that the climate of Yanzhou must have fit that description in very ancient times. Although this would have intrigued many of his readers, the study of paleoclimatology in medieval China did not develop into an established discipline.
  
  The Song dynasty philosopher Zhu Xi (1130–1200) wrote of this curious natural phenomenon of fossils as well. He was known to have read the works of Shen Kuo. Shen's description of soil erosion and weathering predated that of Georgius Agricola in his book of 1546, De veteribus et novis metallis. Furthermore, Shen's theory of sedimentary deposition predated that of James Hutton, whose groundbreaking work was published in 1802 (considered the foundation of modern geology). Historian Joseph Needham likened Shen's account to that of the Scottish scientist Roderick Murchison (1792–1871), who was inspired to become a geologist after observing a providential landslide.