to be taller and healthier compared to children from lower classes. This is most probably due to better diets and less strenuous labor requirements among the elite class. Trade Records show that Dickson Mounds was part of a complex trade network with many culturally diverse populations from the Plains area, the Caddoan area, and Cahokia by 1200 CE. In particular, Cahokia provided Dickson Mounds with luxury items such as copper ornaments and marine shell necklaces in exchange for food items such as meat and fish. The trade of foodstuffs for luxury goods required individuals at Dickson Mounds to generate a surplus of food, resulting in an intensification of agricultural production, which bore serious health and social consequences. Decline The population at Dickson Mounds is said to have inexplicably vanished during the late thirteenth to mid fourteenth century. Possible reasons for the decline of Dickson Mounds are warfare, climate change, and widespread epidemics. Climate change may have had detrimental effects on agriculture, particularly the cultivation of maize, on which the population had become so dependent for subsistence and trade. The significant expansions of the population as well as trade increased contact and transfer of infectious diseases and could also be possible causes of decline. Commemoration The site was listed on the U.S. National Register of Historic Places in 1972. See also List of Hopewell sites List of Mississippian sites List of burial mounds in the United States List of archaeological sites on the National Register of Historic Places in Illinois References Further reading External links Dickson Mounds website Archaeological sites on the National Register of Historic Places in Illinois Havana Hopewell culture Middle Mississippian culture Native American museums in Illinois Museums in Fulton County, Illinois National Register of Historic Places in Fulton County, Illinois Protected areas of Fulton County, Illinois Mounds in Illinois