The varying cultures collectively called Mound Builders were prehistoric inhabitants of North America who, during a 5,000-year period, constructed various styles of earthen mounds for religious and ceremonial, burial, and elite residential purposes. These included the Pre-Columbian cultures of the Archaic period; Woodland period; and Mississippian period; dating from roughly 3,400 BC to the 16th century AD, and living in regions of the Great Lakes, the Ohio River valley, and the Mississippi River valley and its tributaries. (15)

Watson Brake: The Oldest Mound Complex in North America:

Watson Brake is the oldest archaeological site  in Louisiana dating from the Archaic period. It is also one of the the earliest complex construction in the Americas. The complex is made of an arrangement of human-made mounds located in the floodplain of the Ouachita River near Monroe in northern Louisiana, United States. Watson Brake consists of an oval formation of eleven mounds from three to 25 feet (7.6 m) in height, connected by ridges to form an oval nearly 900 feet (270 m) across. The analysis of 27 radiocarbon dates indicates that the site was initially occupied around 4,000 BC during the Middle Archaic period. Mound construction began at approximately 3,500 BC, and continued for approximately 500 years. (6)

The first recognised mound-building culture in the North America's is the Adena culture, which existed from around 1,000 BC - 200 BC, in  a time also known as the 'Early Woodland Period'. (1)

Grave-Creek mound:

Grave Creek Mound, Moundsville, (c. 200 BC). The largest of several funerary mounds in the area.

Grave Creek Mound is probably the most famous of the Adena burial mounds, and certainly one of the most impressive (over 600,000 tons of earth). Not only is it the largest Adena mound, but it is the largest conical type of any of the mound builder structures. In 1838, road engineers measured the height of the mound at 69 feet and the diameter at the base as 295 feet. Originally a moat of about 40 feet in width and five feet in depth with one causeway encircled the mound. Construction of the mound took place in successive stages from about 250-150 B.C., as indicated by the multiple burials at different levels within the structure. The building of the mound and moat must have been a massive undertaking, since the total effort required the movement of over 60,000 tons of earth.

The Inscribed Stone from Grave-Creek Mound: When the mound was opened in 1838, by Mr Tomlinson, the owner of the land, he found skeletons, adorned with plates of mica, copper rings and ivory beads, along with 'The Inscribed Stone'. Although this stone has caused much debate since its discovery, it seems that there is little debate over its existence (As it is held by the Smithsonian Institute). It is still today classified officially as an 'anomalous artefact'. A replica is on display in the local museum. The Grave Creek Stone Smithsonian photograph 90-9022 (MS 3146, E.H. Davis Collection, National Anthropological Archives) The Grave Creek Stone Buffalo and Erie County Historical Library (Image Drawn By P.P. Cherry, Wadsworth Ohio, 1877) There have been numerous discoveries of inscribed Adena tablets since the Grave-Creek mound discovery, supporting the supposition that the Grave-Creek Tablets might be authentic (although there is no reference to any with script). This from Wiki: 'The Adena carved small stone tablets, usually 4 or 5 inches by 3 or 4 inches by .5 inches thick. On one or both flat sides were gracefully composed stylized zoo-morphs or curvilinear geometric designs in deep relief. Paint has been found on some Adena tablets, leading archaeologists to propose that these stone tablets were probably used to stamp designs on cloth or animal hides, or onto their own bodies. Its possible they were used to outline designs for tattooing. (1) Article: (P.P. Cherry, 1877) - 'The Grave-Creek Inscribed Stone, with its Vindication'.  (Quick-link)

 

The Ohio Serpent Mound.

Long believed to be a part of the Adena Culture based on the presence of Adena burials nearby. This serpent effigy (the largest in the world) is now attributed to the later 'Fort Ancient' culture. (3). It has been proposed (2) (3), that the serpent mound was an astronomically based, symbolic landscape feature:

'Lunar alignments correspond to six of the seven coils of the serpent effigy. The coils to the right point to the moon's maximum northern, southern, and central rising points, and the coils to the left point to the moons maximum northern, southern and central setting points. As such, the serpent is closely identified with the moon, and with the underworld. The head and oval also point to the sun's maximum northern setting point, during the summer solstice, and appear to show the sun symbolically being "swallowed" by the serpent. The serpent is also aligned to true north via a line travelling from the centre of its coiled tail to the base of its head'. (2)

(More about Archaeoastronomy)

 

Adena Shamanism: Although the mounds are beautiful artistic achievements themselves, Adena artists created smaller, more personal pieces of art. Art motifs that became important to many later Native Americans began with the Adena. Motifs such as the weeping eye and cross and circle design became mainstays in many succeeding cultures. Many pieces of art seemed to revolve around shamanic practices, and the transformation of humans into animals�particularly birds, wolves, bears and deer�and back to human form. This may indicate a belief that the practice imparted the animals' qualities to the wearer or holder of the objects. Deer antlers, both real and constructed of copper, wolf, deer and mountain lion jawbones, and many other objects were fashioned into costumes, necklaces and other forms of regalia by the Adena. Distinctive tubular smoking pipes, with either flattened or blocked-end mouthpieces, suggest the offering of smoke to the spirits. The objective of pipe smoking may have been altered states of consciousness, achieved through the use of the hallucinogenic plant Nicotiana rustica. All told, Adena was a manifestation of a broad regional increase in the number and kind of artefacts devoted to spiritual needs.

(More about Shamanism)

By about 200 B.C., the Adena culture had given way to the more sophisticated Hopewell tradition.

The 'Hopewell tradition' is the name used to describe the common aspects of the Native American culture that flourished along rivers in the north-eastern and mid-western United States from 200 BC to 500 AD. The Hopewell tradition was not a single culture or society, but a widely dispersed set of related populations. They were connected by a common network of trade routes, known as the Hopewell Exchange System.

The great geometric earthworks are amongst the most impressive monuments throughout American prehistory.

 

(Other Images of Hopewell Geometric Earthworks)

(Archaeoastronomy)

Platform (Effigy) Pipes:

The Hopewell tradition is also known for the discovery of several large caches of effigy (or platform) pipes. Most famously, the 136 from Tremper mound, and the cache of nearly 250 animal and human effigy pipes from Mound 8 at Mound City north of Chillicothe They are found broken, or 'killed', in large crematory basins. (4)