Effigy Mounds and Lascaux

The effigy mounds erected between 700 A.D and 1200 A.D placed the world into two categories, that of the upper-world and lower-world. The upper-world consisted of the Thunderbird, the most powerful spirit in this realm, the hawk and other avian species. The lower-world of water consisted of water spirits, often represented as a water panther, who ruled  the lower realm, and then the bear who ruled the terrestrial division of the lower world. Two interesting aspects of these mounds, their locations and way they conform to the land, suggest that they were built to preserve harmony in nature and way of life of Native Americans. 

Considering that many rituals and ceremonies relied on these mounds for significance it is likely that they represented a "general order of existence" much in the same way as religious texts like the Bible and Koran do for today. 

The way that animal representations were used, in my opinion, in mississippian culture is similar to the way we use animal figures for sports teams today. Upper-world beings such as the hawk and peregrine falcon were associated with  power and strength, and subsequently were used in the adornment of warriors as can be noted in cave paintings. Today, animals with characteristics of strength and agility, such as bears and  wolves can be found commonly in sports team names because they represent traits that are desired in the activity.

When it comes to the Lascaux caves, I think the most important difference between it and the effigy mounds is the realism of the animal paintings which lack the obvious mythical aspect of the mounds. This may be an indicator of a less than religious aspect of the Lascaux cave paintings. However the two are the same in that they both represent what was of significance to the two groups and nature also played a large role in the formation of both works.