Washington: Human skeletons estimated to be about 850-years-old have been found by a group of excavators at an archaeological site in Mexico.

The skeletons were found at an archaeological site at Sierra Gorda in the central state of Queretaro during consolidation work of a pre-Hispanic structure - Building 17 of Huastec complex.

Jorge Quiroz, head of the excavation project, said the skeletons can be as old as 1150 DC, about two centuries after Tancama had been vacated by pre-historic locals.

"People who already lived in other places, came back to this city to deposit their dead in some of its structures (necropolis). This hypothesis might only be corroborated with further studies," Quiroz was quoted saying by Artdaily.

According to Cristina Garcia Pura, Doctor in Physical Anthropology, the skeletons have incision marks which might be signs of sacrificial offerings.

"When the incision marks' studies have been made, we will know if they were victims of a sacrifice or if these were skulls that were used as secondary burials (meaning they were removed from another place). All were found grouped together and four of these craniums were linked to the bones of hand and feet among others.

"Although a bio-archaeological study has not yet been made, this type of findings usually belongs to sacrificial offerings, since in that time (500-700 DC) in Mesoamerica, the feet, the hands and the craniums were considered the most important parts of the human body. So they were obliged to use them in burials," Garcia Pura said.

The skeletons have been moved to the Department of Archaeological Comparative Collections of Instituto Nacional de Antropologia e Historia (INAH) in Mexico for a through analysis of the bones, to determine their age, gender and possible sicknesses that might have lead to the individual's demise.