San Miguel Ixtapan, Mexico - PART I: THE INCREDIBLE MAQUETA STONE

A small site in the southern part of the state of Mexico, virtually unknown until it was only partially excavated in the early 1990’s, may hold the evidence of an unknown civilization that flourished at the same time as the mysterious Olmecs and left some incredible stone monuments that have no equals in other parts of Mexico and Mesoamerica.

The small archaeological site of San Miguel Ixtapan is located in the south of the State of Mexico, at the entrance of the Tierra Caliente region that from the highlands of Central Mexico leads down to the Pacific coast. One gets there from the city of Toluca on highway 134 after passing the town of Tejupilco de Hidalgo, or from the popular lake resort town of Valle de Bravo, from which it is only about 70 kilometers (45 miles) distant.

The enigmatic Cerro de la Muñeca, dominating the site of San Miguel Ixtapan from the distance and the subject of many curious legends and local traditions. [Photo by Author]

The site is only one of a handful that has been at least partially explored in the southwestern part of the State of Mexico, an otherwise blank spot on the archaeological map of Mexico. Its discovery only dates to 1985, when a huge sculptured “maqueta” model stone was uncovered by farmers plowing a field near the local cemetery. It was not until 1995 that a small portion of the site, including parts of a large pyramid and a Mesoamerican ball court – only one of three known in this part of Mexico – were excavated.

A view of the 40-meter long ballgame court of San Miguel Ixtapan, one of only three known in the State of Mexico. [Photo by Author].

A sunken patio on the south side of Basement 3. The “Recinto de las Esculturas” (Enclosure of the Sculptures) is found under the roofed structure next to a corbelled chamber also protected by a roof. [Photo by Author].

A panoramic view of the excavated portion of the site of San Miguel Ixtapan from a nearby unexcavated pyramid mound known as “El Calvario”. [Photo by Author].

The earliest traces of human occupation in the area date back at least 12,000 years, in the form of cave paintings in the nearby Sierra de Nanchititla. An unknown culture then occupied the site around 2,000 BCE. To this remote period dates a human burial found on top of a still unexcavated pyramid mound or platform, which contained a mosaic stone mask, another smaller mask made of jadeite with Olmecoid features, and a jade beads necklace, together with human remains that provided a chronological reference date for the burial (Sinaí Gomez, 2012).Since the time of the site’s discovery, several subsequent excavation campaigns have revealed at least five different periods of occupation of the site during the Formative, Pre-Classic, Classic, Epi-Classic and Post-Classic period.

Part of an offering discovered near the summit of an unexcavated mound in San Miguel Ixtapan during electrical works. It includes a mosaic stone mask, a jade necklace, earrings and a small pendant in the shape of a human head with possibly Olmecoid (?) features. A burial associated with the offering has been allegedly dated to 2,000 BCE. The culture that produced these artefacts is completely unknown. [Photo by Author]. 

A detail of the small Olmecoid (?) green stone mask associated with the offering. [Photo by Author]

A set of enigmatic stone idols with crossed arms, part of a larger offering found in the “Recinto de las Esculturas” (Enclosures of the Sculptures) area of the site, dated to the Epiclassic period (650-900 CE) [Photo by Author]

Mezcala culture (700 BCE - 650 CE) stone figurines from the Site Museum of san Miguel Ixtapan. [Photo by Author]

Several Formative period ceramic figurines were also found, dating to between 800 and 200 BCE, showing affinities with the Tlapacoya and Tlatilco artistic tradition of Central Mexico. The discovery of a number of Teotihuacan style artefacts further testify to the site’s occupation during the Classic period, when it either came under direct political control or was influenced by Teotihuacan. After the fall of Teotihuacan, in what is known as the Epi-Classic period (750-900 AD), the site knew its greatest expansion, with the construction of several monumental structures and pyramids rivaling in size other nearby sites like Teotenango and Xochicalco.

After a period of abandonment, the site was then reoccupied by the Aztecs in the Post-Classic period, and remained inhabited until the time of the Spanish conquest.

The site nowadays consists of a large pyramidal platform with a temple and smaller rooms on top in which several sculptures were found, a Mesoamerican ball court, a monumental stairway built of large basalt blocks, and a sunken courtyard. Some very notable sculptures were found in niches and chambers of the main pyramid (also known as Basement 3), including a large stela with a depiction of the rain god Tlaloc, and multiple anthropomorphic figures with unusually crossed arms, a pose quite rare in ancient Mexico and with possible funerary significance.

The front of Basement 3, with another monumental stairway built of large basalt blocks. It is possible to appreciate the different stages and epochs of construction of Basement 3 in the alternation between different masonry styles. [Photo by Author].

The "Patio de las Esculturas" (Enclosures of the Sculptures" located on a terrace of the main pyramid, with two monolithic stone slabs and idols still in the same original archaeological setting where they were found during excavations in the mid 1990's. [Photo by Author]

A view of Basement 3, the largest pyramid at the site, from which it is possible to appreciate the monumental stairway leading up to the ballgame court plaza and a drainage channel on one side of the structure. [Photo by Author].

A detail of some huge basalt blocks that would have formed part of the monumental stairway. [Photo by Author].

The shrine to Tlaloc, on one side of Basement 3, where the Tlaloc stela was found. [Photo by Author].

A stela with an early depiction of the god Tlaloc. [Photo by Author].

A circular stone marker found in the ballgame court of San Miguel Ixtapan and dating to the late Epiclassic period (ca. 650-900 CE). [Photo by Author]. 

The site is also home to a small but very interesting site museum containing a wealth of objects found during the early 1990’s excavations, including ceramics, stone and jadeite ornaments, obsidian knives and points, copper and bronze artefacts (including a remarkable necklace with exquisitely worked human heads and figurines made of copper), as well as stone sculptures, votive offerings and a stone ring associated with the ballgame court. The artefacts show a remarkable range of trade interactions and a definite influence from the Mezcala culture of Guerrero and the Balsas river culture. The location of San Miguel Ixtapan was probably considered strategic on account of the presence of salt mines, still in use since prehispanic times, and of large deposits of columnar basalt providing readily available material for construction.

Part of a megalithic basalt wall and stone arrangement on the opposite site of the ravine from the site museum of San Miguel Ixtapan. [Photo by Author].

Another view of the same basalt stone arrangement employing huge megalithic stone blocks. [Photo by Author]

A monumental andesite pillar, nearly 2 meters high (the notebook is for scale), unfortunately defaced by graffiti, standing on one side of the parking lot of the archaeological site. Originally part of an arrangement of 3 similar pillars, it is the only one still standing. [Photo by Author].

The incredible “Maqueta” Stone model

The “Maqueta” stone is a huge carved basalt stone boulder, measuring some 3 by 4 meters. It was this stone, uncovered by farmers plowing a field, which first called archaeologists to the site in 1985. The huge stone is entirely covered in miniature representations of architectural structures believed to represent a city (whether real or imaginary is a matter of speculation), complete with temples, pyramids, at least five ballgame courts, plazas and sunken courtyards, all connected by avenues and stairways. Similar examples of prehispanic architectural models are known to exist from Xochicalco, Morelos; Plazuelas, Guanajuato; Valle de Bravo, Mexico (see our recent article and story here); Teotihuacan (Mexico), as far as Tikal, Guatemala. Among these, the one of San Miguel Ixtapan is possibly the largest and most complex, comparable to the famous Sayhuite stone of Peru.

The incredible “Maqueta” stone model of San Miguel Ixtapan, carved from a single huge boulder of basalt measuring 3 by 4 meters and believed to contain the representation of a yet unidentified city. Seen from the West. [Photo by Author]

Another view of the same "Maqueta" stone, from the North. [Photo by Author]

The "Maqueta" stone from the North, showing its left portion. [Photo by Author]

The "Maqueta" stone from the North, showing its central portion. [Photo by Author]

        Several attempts have been made to identify the site depicted on the stone, seemingly a hilltop ceremonial center of exceptional scale and complexity, but these attempts have so far proven entirely fruitless. It is possible that the stone portrays a yet undiscovered site, perhaps located in the mountains to the north and east of San Miguel Ixtapan, or that the city depicted was purely imaginary, a votive representation of an idealized place or sanctuary. It may well be a city that is still lost or the drawing of a city yet to be built.

A view of the "Maqueta" stone from the West [Photo by Author].

A set of monumental structures in the lower sector of the “Maqueta” stone, among which it is possible to observe the typical ‘I’ shape of a Mesoamerican ballgame court. The rock-cut temples and structure in the upper part of the picture resemble similar examples of rock-cut monolithic architecture from Malinalco and Acatzingo de la Piedra, also in the state of Mexico [Photo by Author].

Another view of the same sector of the “Maqueta” stone, showing a row of buildings inside what appear to be rock-cut trenches and a large pyramid complex and plaza below, now quite eroded. [Photo by Author].

An interesting double pyramid approached by a monumental stairway and facing a small plaza. [Photo by Author].

A detail of the main pyramid complex occupying the center of the “Maqueta” stone with a sunken courtyard approached by monumentalized stairways on three sides. [Photo by Author].

Another sector of the monumental “Maqueta” stone depicting what appear to be various rock-cut chambers and stairways below the main pyramid complex. [Photo by Author].

The depiction of a pyramid approached by a monumental stairway facing a Mesoamerican ballgame court with the typical ‘I’ shape. [Photo by Author].

A detail of the sunken courtyard or plaza to the West of the main pyramid complex, approached by monumental stairways on three sides. [Photo by Author].

The main pyramid complex, consisting of a large three-tiered pyramid, a plaza in front of the main pyramid with lower building or platforms on the sides and a monumental stairway giving access from the level of a lower plaza. The sunken courtyard is to the right of the main pyramid [Photo by Author].

A view from the South and from above of the lower sector of the "Maqueta" stone, showing various groups of buildings. The main pyramid complex is above in the picture. [Photo by Author]

A model temple sculptured on a separate piece of rock, from which it is possible to appreciate the stairway leading up to the temple and altar on top. [Photo by Author].

        There are no definite elements for dating the “Maqueta” stone, but archaeologists mostly favor a date in the Epiclassic or early Postclassic period (ca 900-1200 AD).

        In the second part of this article we will be discussing some of the other evidence of high-precision megalithic architecture in San Miguel Ixtapan.

- CONTINUED IN PART II -

Acknowledgements

We would like to thank archaeologist Victor Osorio Ogarrio, director of the site and archaeological museum of San Miguel Ixtapan for his kind permission to visit the “Recinto de las Esculturas” and for accompanying us on our visit to Rancho “I”.

The opinions expressed in this article are solely the Author’s and do not necessarily reflect the opinions and beliefs of Dr. Osorio, of the National Institute of Anthropology and History (INAH), or of the Secretary of Culture of the State of Mexico.

References

[1] INAH, “Zona Arqueológica de San Miguel Ixtapan”, on January 9, 2008. On-line resource: https://www.inah.gob.mx/zonas/46-zona-arqueologica-de-san-miguel-ixtapan. Accessed on April 20, 2021.

[2] Malmstrom, Vincent H. “Geographical Origins of the Tarascans”. Geographical Review, vol. 85, No. 1, January 1995, pp. 31-40.

[3] Osorio Ogarrio, Victor Ángel and Marco Antonio de León Cortés. “Una posible Diosa Prehispánica en San Miguel Ixtapan, Tejupilco”, Arqueología Mexicana, 158, July-August 2019, pp. 46-51.

[4] “Revista cultural San Miguel Ixtapan”, Expresión Antropológica, no. 1-2 Nueva Serie. Gobierno del Estado de México: Secretaría de Cultura, 1999.

[5] Reyna Robles, Rosa María, La Cultura Arqueológica Mezcala, Instituto Nacional de Antropología e Historia, 2006.

[6] “San Miguel Ixtapan, Estado de México”, Arqueología Mexicana, Especial 35, Estado de México, guía arqueológica, June 2010.

[7] Sinaí Gomez, Rodolfo, “Antecedentes Históricos - Tejupilco”, Municipio de Tejupilco, 2012. On-line resource. Accessed on April 25, 2021 through Archive.org: https://web.archive.org/web/20120327194635/https://www.tejupilco.gob.mx/contenido/index.php?option=com_content&view=article&id=59&Itemid=59

[8] Wikipedia, “San Miguel Ixtapan (Archaeological Site)”. Last edited on December 19, 2020. On-line: https://en.wikipedia.org/wiki/San_Miguel_Ixtapan_(archaeological_site). Accessed on April 20, 2021.

The Lost City of the Eagle

A mysterious Olmec presence in the Mixteca

     Huehuepiaxtla is a small town located in the heart of the Mixteca region, 150 kilometers (100 miles) south of Puebla. Overlooking the town is a huge isolated peak, called by locals ‘La Peña’ – The rock. Tradition has it that the mountain was home to the first inhabitants of the region, who were later turned into stone by the gods.

The municipal president of Huehuepiaxtla, Dr. Florencio Dominguez (left) and our guide German (right) near a section of megalithic stone wall decorated with the image of an eagle on the summit of the Great Rock of Huehuepiaxtla [Photo by Author]

I first became interested in this mysterious site after coming across pictures online of what appeared to be several broken stelas and bas-reliefs [1]. There were also rumors of more extensive ruins near one of the peaks, including great stone walls and a broken obelisk. After contacting the local authorities, the municipal president Dr. Florencio Domínguez was kind enough to arrange for a guide and equipment to climb the peak and document whatever ruins we might find on top.

Upon arriving in Huehuepiaxtla, the summit of the Peña was still entirely shrouded in the morning mist. After the necessary preparations, we approached the cliff from the West. The peak now loomed directly a full 450 meters (1,470 ft) above us and the Rio Mixteco running below. Luckily, no rain had fallen in the past few days, so the rock was quite dry. Florencio explained that had it rained the night or the day before, the rock would have been too slippery to climb. Our guide, German, was an expert climber and one of very few people in town who know the difficult trail to the top.

The Great Rock of Huehuepiaxtla, as seen from the Mixtec River running below and around it. [Photo by Author]

Already at 10:00 am the temperature was nearly 30°C. Near the base of the cliff, we walked through a large flat area, trapezoidal in shape, which appeared to have been artificially leveled with steep embankments on all sides. Some overgrown mounds on the western side suggested this might have been a ceremonial plaza flanked by pyramids.

From there, a small trail led directly to the base of the cliff. Some steps and ledges had been originally carved in the rock, but these were now very worn. The path required to go through some very steep sections of exposed bedrock, which made the climb particularly difficult even in dry weather.

The steep trail leading up to the summit of the Rock of Huehuepiaxtla. [Photo by Author]

Another section of the difficult trail along the exposed cliff face, overlooking the village of Huehuepiaxtla and the Mixtec River below. [Photo by Author]

Along the trail we observed several pieces of obsidian and fragments of pottery. About half-way up, we passed through a set of terraces with massive stone retaining walls. The quality of the visible stonework varied, with some sections composed of huge, finely fitted rectangular stone blocks and others formed of rough boulders. The stone appeared to be a kind of basalt, which was probably sourced locally from the slopes of the great rock itself. 

Dr. Florencio holding a piece of obsidian, probably a small arrowhead, found along the trail to the summit. Note: No artifact was removed during the exploration, and all pieces were returned to their original location. [Photo by Author]

The handle of a broken ceramic vessel. Note: No artifact was removed during the exploration, and all pieces were returned to their original location. [Photo by Author] 

A partially exposed section of a megalithic stone wall about half-way towards the summit of the Great Rock. Some of the larger stones in the picture measure up to 3 meters (10 ft) long. The style of construction is reminiscent of Chimalacatlan and Huaxtla, two early Pre-Classic sites in the state of Morelos.[Photo by Author]

A retaining wall formed of large roughly shaped boulders laid without cement. [Photo by Author]

Some large broken sections of megalithic stone walls, like the one in the picture, suggest the existence of buried monumental structures on this side of the hill. [Photo by Author]

After some more climbing, we finally reached the summit at about noon. The summit consists in fact of a small, mostly level plateau or ridge in between two separate peaks, one to the East and the other to the West. This plateau contained extensive remains of ancient constructions and some overgrown mounds. However, the thick vegetation made it impossible to make out but the general outline of most of the structures.

The small cross located on one of the peaks of the Great Rock of Huehuepiaxtla, overlooking the town and the river below. [Photo by Author]

A rock ledge overlooking the Mixtec River 450 meters below. Note how the rock appears to have been artificially leveled and cut into steps. Several glyphs and rock carvings can be found in this area. [Photo by Author]

Opening our way with machetes through the thick undergrowth we reached the first of the two peaks, where a small cross has been erected that is visible from the town below. From there, it was possible to descend towards a rock ledge directly overlooking the river 450 meters (1,470 ft) below. The ledge appeared to have been artificially leveled and carved into steps or terraces, each just a few meters wide. Various glyphs and symbols were apparently carved on the rock, suggesting that this was in fact a very important point in the sacred geography of the area. Among the glyphs that we could make out were two apparent calendar symbols including the numeral ‘9’ and the figure of an eagle or vulture. The uppermost terrace, where the eagle bas-relief could be seen, was once delimited by a massive megalithic stone wall that emerged directly from the natural bedrock. The joints between the stones looked extremely tight, except for a point where some tree roots had partially dislodged a large vertical block. According to our guide, the peculiar arrangement of the stones around the eagle glyph indicated a hidden passageway. What made the existence of a passage through the rocks very likely was the presence of another bas-relief, depicting a crouching jaguar, which appeared to continue beyond the joint into the wall. From this point, it was also possible to see the entrance of another cave near the base of the cliff. Local traditions speak of vast subterraneans under the Peña. One of these is said to be covered in carvings and mysterious figures, but no entrance to these subterraneans is presently known.

A mysterious glyph on one of the rocks near the eagle carving. [Photo by Author]

A section of what appears to be a megalithic stone wall with the carving of an eagle and a calendar glyph with the numeral '9'. Note the peculiar arrangement of the stones to the right of the carving, allegedly concealing the entrance to a subterranean. [Photo by Author]

A close-up view of the eagle glyph on the same rock face. The figure of a jaguar can be faintly made out to the right of it. [Photo by Author]

Another glyph near the edge of the rock overlooking the Mixtec River some 450 meters below. The glyph is inscribed inside a circle and is also accompanied by the numeral '9', represented by a bar with four dots. [Photo by Author]

From this rock ledge, we continued along a trail overlooking the precipice in the direction of a small plateau separating the two peaks. There, in a small plaza facing an ancient overgrown pyramid lay one of the most fascinating monuments of antiquity in this parts of Mexico. It was a huge fallen stela, some 3 meters (10 ft) long, carved on one side with the image of an undefinable creature. It had slightly open legs, from which emerged what appeared to be a tail. Hands and feet looked like claws, but the creature appeared otherwise humanoid. The head could be that of a bat, with large pointed ears. The presence of clearly marked breasts suggested that the subject represented was a female. It was a unique type of stela, for the deeply embossed relief and the frontal depiction of the main figure. The stela was probably part of a pair that had been once erected in front of the main pyramid. Another fragmentary stela, now in the main square of Axutla, is also said to have been found at Huehuepiaxtla, and shows a very similar iconography. In this latter case, however, the figure depicted looks clearly human, possibly a dancer. The stela of Axutla is also significantly smaller, and the carving much shallower and less precise.

A large fallen stela in front of the main pyramid on the summit of the Great Rock of Huehuepiaxtla. The figure depicted is vaguely anthropomorphic, with claws in the place of hands and a curious head with pointed ears resembling a bat. [Photo by Author]

Another view of the same fallen stela with a smaller stone block that may have been its base or an offering table, also near the base of the main pyramid. [Photo by Author]

A view of what appears to be the main pyramid of the site, with its partially exposed stone core. [Photo by Author]

After passing the main pyramid, the trail led in the direction of the second peak. About half-way up towards the summit, we found a pair of strange megalithic arrangements. The first apparently consisted of some huge boulders, each probably weighting 1 ton or more, roughly piled up to form some sort of cairn about 3 meters (10 ft) high. A short distance from this first arrangement was a second one, consisting of even larger basalt columns stacked together as to form a fence. I found the resemblance to the famous Olmec megalithic tomb of La Venta particularly striking, especially for the use of prismatic basalt columns. From there, we entered another small plaza delimited on three sides by a stone wall. The wall had entirely collapsed, but the debris still reached up to 1 meter (3 ft) in height. The purpose of the wall was probably to delimit a sacred precinct in front of another very ruined pyramid that occupied the summit of the second peak. A large hole could be seen where a temple would have stood on top of the pyramid, probably dug by looters in search of treasure. From this vantage point it was possible to see at a distance of some 5 kilometers another giant rock, known as the Peña de Tlaxcuapan, where more ancient ruins are said to exist. 

A cairn formed of huge megalithic stone boulders on the summit of the Great Rock of Huehuepiaxtla. It is possible that these stones once formed part of some large fallen structure. [Photo by Author]

A curious megalithic arrangement consisting of several basalt columns, each up to 3 meters (10 ft) high. This is reminiscent of the famous Olmec tomb of La Venta, probably early Pre-Classic. [Photo by Author]

A view of the Rock of Tlaxcuapan from the summit of small pyramid that occupies the second peak of the Great Rock of Huehuepiaxtla. [Photo by Author]

We then began a difficult descent along a small overgrown pathway towards a spot where our guide German claimed a huge broken stela or obelisk could be found. After a turn, we found ourselves in front of an immense stone wall, formed of huge megalithic blocks up to 4 meters (13 ft) long, laid in regular courses without mortar or cement. The wall apparently formed the side of a large stone platform or terrace, on top of which rose a second platform also lined with great megalithic stones. The overall impression was one of extraordinary antiquity. Near the base of the lower platform we found another curious arrangement of basalt columns, each probably 3 or 4 meters  (10-13 ft) long, placed horizontally as to form a kind of bridge. We could not determine whether the columns actually formed part of the roof of some buried structure, but this seemed very likely. A short distance from there we reached the ‘Stone of Sacrifice’. This was in fact an enormous broken stela, which may have stood up to 6 meters (20 ft) tall when still erect, but which now lay broken in four parts. The decoration on the stela betrayed a clear Olmec influence. Although now badly defaced, it probably depicted a ruler crowned by what appeared to be a very elaborate headdress.

A set of huge monolithic basalt columns laid horizontally as to form a sort of bridge, possibly the roof of a tomb. [Photo by Author]

A section of a massive megalithic wall forming the side of a terrace. Some of the stones pictured above measure over 3 meters (10 ft) long, with a weight of several tons. [Photo by Author]

Another view of the same megalithic terrace, formed of massive prismatic basalt columns laid in rows without mortar or cement. Probably early Pre-Classic. [Photo by Author]

More ruined megalithic stone walls, partially covered by vegetation. [Photo by Author]

A view of some other megalithic structures on the upper terrace, also built of huge blocks of prismatic basalt laid without mortar or cement. [Photo by Author]

The great broken stela known as the 'Stone of Sacrifice' at the base of the lower terrace. The fragment on the left shows a badly eroded head and torso, while the larger fragment on the right contains part of an elaborate headdress. The style of the sculpture is typically Olmec. When erect, the stela (now broken in at least four pieces) would have stood at least 6 meters (21 ft) tall. [Photo by Author]

More Olmec-style carvings could be found near the base of the Peña. These appeared to have also been part of another large broken stela. A glyph accompanied by the numeral ‘4’ could be seen on one of the fragments.

Fragments of a large broken stela found near the base of the Rock of Huehuepiaxtla. A glyph with the numeral '4' can be clearly made out in the center of the picture. [Photo by Author]

More fragments of the same broken stela, with apparently Olmec carvings. [Photo by Author]

The rock of Huehuepiaxtla was certainly a very important site in ancient times, and it is a pity that so little is known about it. Everything suggests that this was a major ceremonial center in the Pre-Classic period, probably as early as 1,000 B.C., and may be related to the other Olmec sites in the region, at Chalcatzingo, Chimalacatlan, Huaxtla, Teopantecuanitlán and Juxtlahuaca.

The possibility of a connection between these sites is further suggested by the fact that a line drawn through Chimalacatlán and Huaxtla (as described in a previous article [2]) leads directly to the rock of Huehuepiaxtla. A continuation of the same line crosses the nearby rock of Tlaxcuapan and ends at Apoala. This alignment of five sites, all displaying unusual megalithic architecture, appears to be hardly coincidental.

It is only to be hoped that the Mexican Institute of History and Anthropology (INAH) also gathers an interest in this now forgotten site and helps preserve it from looting for the benefit of future generations.  

A herd bathing in the Mixtec River, at the base of the Great Rock of Huehuepiaxtla. [Photo by Author]

Another view of the Rock of Huehuepiaxtla, standing in monumental isolation in the hilly landscape of the Mixteca. [Photo by Author]

Part of a broken stela, allegedly from Huehuepiaxtla, found in the main square of the town of Axutla. [Photo by Author]

Another stone fragment in the main square of Axutla, possibly from the same stela. [Photo by Author]

References

Unfortunately, no bibliography could be found concerning Huehuepiaxtla and its ruins, as the site is presently unpublished and no mention of it exists in academic literature. 

[1] La Gran Peña, origen de mitos y leyendas en la Mixteca poblana y oaxaqueña, in MunicipiosPuebla.mx, December 22, 2013 – On-line resource: http://municipiospuebla.mx/nota/2013-12-22/acatl%C3%A1n-de-osorio/la-gran-pe%C3%B1a-origen-de-mitos-y-leyendas-en-la-mixteca-poblana-y

[2] Marco M. Vigato, Tamoanchan, in Search of the Lost Cradle of Mesoamerican Civilizations, in Ancient Origins, February 9, 2019 – On-line resource:https://www.ancient-origins.net/ancient-places-americas/tamoanchan-0011452

Also on this blog: The Location of the Mesoamerican ‘Hall of Records’ at Chalcatzingo: http://unchartedruins.blogspot.com/2016/11/the-location-of-mesoamerican-hall-of.html - Note the striking similarity between the profile of the rock of Chalcatzingo and the Peña of Huehuepiaxtla, as if to suggest that these may have in fact been sister sites belonging to the same culture