More than 500 Prehispanic lithic objects and ceramic fragments were discovered in different points of the border between San Luis Potosi and Guanajuato. Among artifacts, arrowheads elaborated by Prehispanic nomadic groups outstand.

With an antiquity range that goes from 1000 BC to 1800 DC, artifacts were found in 37 different sites distributed in 5 areas that correspond, according to historical sources to those occupied in the 16th century by Guachichil and Guamar tribes, part of the cultural region known as Great Chichimeca.

Archaeologist Ruben Manzanilla, from the National Institute of Anthropology and History (INAH), informed that between localized items are lithic tools such as scrappers, knives and projectiles, elaborated mainly with rhyolite of different colors and qualities. Other material found was flint, basalt, quartz and obsidian.

A rock painting with the representation of a heron made with mineral red pigment was located, as well as a petroglyph that may represent a human face.

Among stone items, small projectiles made out of grey and green obsidian stand out, as well as others created with white flint. They correspond to the last occupation stage denominated Tunal Grande (1200-1800 AD).

“According to historical sources, this kind of arrowheads was used by indigenous nomads during Chichimeca War, which was fought against Spaniards in 16th century, because they wanted to conquer the Camino de la Plata (Silver Road) that communicated the New Spain with Guanajuato and Zacatecas.

“Points were sharp, and chroniclers mentioned how they went through mail coats and armors of European soldiers, severely injuring or killing them”, commented the archaeologist.

He mentioned that finding the place where this kind of obsidian was collected is important; “although chronicles indicate Chichimeca groups were disperse, they recognized themselves with different ethnic names, having strong exchange links.

“Finding through which routes, and how the volcanic material was distributed, brings in data regarding who exploited it and about relations of hunter-gatherer groups of Great Chichimeca and Sierra Gorda in Guanajuato and Queretaro”.

The INAH archaeologist declared that earliest historical antecedents of Prehispanic occupation of the zone are found in the 16th century work called Guerra de los Chichimecas, written by Augustinian friar Guillermo de Santa Maria in 1580.

Ruben Manzanilla mentioned that grinding stones elaborated by sedentary groups were found as well; “this fact verifies that hunter-gatherers exchanged product with sedentary people; pray, furs, and stone tools might have been traded for ceramics or polished lithic objects. These activities were historically documented and now they have been verified”.

He declared that in some camps, fragments of Prehispanic ceramic pieces from agricultural groups from Villa de Reyes, San Luis Potosi, were found, confirming there were relations between nomadic and sedentary groups; in this case, it happened between 700 and 900 AD.
In other camps, 16th century Colonial ceramics from Michoacan, and 17th century maiolica from Puebla were recovered.

Manzanilla remarked these findings took place during the construction of El Realito Dam , in the border between Guanajuato and San Luis Potosi: 3 occupation stages were determined, parting from an already-established regional chronology: Venadito Phase (1000 BC-200 AD); Huerta Phase (200-1200 AD) and Tunal Grande Phase (1200-1800 AD).

Lifestyle of hunter-gatherers was always the same, as well as their cultural material, “making difficult to determine the group to which camps were affiliated, Gumar or Guachichil”, concluded the INAH specialist.