Tamaulipas Maize

Excavation profile with arrows indicating the location of Maize, La Perra Cave, Sierra de Tamaulipas.

Contributed by John Bergman-McCool

This blog represents the thirteenth entry in a blog series – Peabody 25 – that will delve into the history of the Peabody Institute through objects in our collection. 

If you travel on state routes through the Northeast this time of year, you will likely witness a continuous stream of hand-painted signs advertising sweet corn. On a recent road trip through Maine, the oft-repeating signs got me thinking about all the places I’ve seen corn cultivated: Washington State, Arizona, the Midwest cornbelt and New England. A quick search on the internet reveals that modern corn varieties can be grown in USDA hardiness zones 3-11 (that’s just about everywhere!). Currently corn is an important crop for many economies across the globe (map of world corn production).

With corn seemingly grown nearly everywhere, you may wonder when and where did it first originate? This question has been the subject of debate among scientists for more than a century. Richard “Scotty” MacNeish, former director of the Robert S. Peabody Institute of Archaeology and influential twentieth century archaeologist, played an important role in untangling maize’s history of domestication.

While a doctoral candidate in 1945, MacNeish was sent to Texas and northern Mexico to look for evidence supporting the theory that Mesoamerican migration into North America led to the development of mound building cultures. MacNeish found no link, but he did locate a series ruins, campsites, and dry caves that had the potential for long sequences of human occupation in Tamaulipas, a state in northern Mexico.

In 1948, MacNeish returned for a field season that included the excavation of three cave sites in the Sierra de Tamaulipas. The caves housed a surprising amount of very well preserved botanical remains. During the closing moment of the excavation in Tamaulipas, the crew had all but closed up shop and shipped off their specimens and equipment when three small maize (corn) cobs were recovered from La Perra cave. The excavations in Tamaulipas pushed the age of maize cultivation back to 2,500 BC. The discovery of what was then the earliest evidence of domestication in the Americas would shape the direction of MacNeish’s archaeological research.

Pre Nal-Tel maize fragment from La Perra Cave, Sierra de Tamaulipas.

A little over a decade later, spurred by colleagues in botany, MacNeish would search farther south for earlier evidence of maize cultivation. In 1961, after years of survey in Central America and southern Mexico, MacNeish found promising dry caves in the Tehuacán valley of Mexico. There he led a multidisciplinary team in the excavation of six cave sites. Among the many discoveries were maize remains recovered from layers dating to 4,700 BC. Tehuacán was theorized as the ancient seat of maize domestication.

Radiocarbon dating techniques utilized by MacNeish in Tamaulipas and Tehuacán required large amounts of carbon, frequently charcoal, that would be destroyed during the dating process. The resulting age was then assigned to artifacts (corn, stone tools, bone, etc.) that were found in the same layer as the charcoal. Developments in radiocarbon made in the 1980s meant that much smaller samples were required, reducing the chance that sampled artifacts would be completely destroyed. When this direct method was applied to maize from Tehuacán and squash from Tamaulipas, the results were up to 2,500 years younger than previously thought.

MacNeish’s comments in the margins of Bruce Smith’s 1995 book The Emergence of Agriculture.

The revisions resulted in prickly disputes about the age of domestication in the Americas. Eventually the dust up resulting from the new dating technique settled, due in part to new dates obtained from squash seeds that rooted domestication to an earlier date of 8,000 BC in Mexico.

MacNeish remained resolute that the dates he derived were accurate up until he passed in 2001. In 2012, Archaeologists returned to the cave sites in the Tehuacán Valley in search of maize remains. The team recovered new maize samples that corroborated the younger age for Tehuacán maize.

Recent research within the fields of microbiology and DNA have focused on the teosinte plant and the Balsas River as the probable ancestor and location for earliest cultivation of maize. Analysis of the DNA suggests that the plant was cultivated as early as 7,000 BC.

The fact that MacNeish did not locate the cradle of corn, shouldn’t take anything away from the massive effort he and his colleagues undertook during their search. As for the Tamaulipas maize, MacNeish himself credits his project in Tamaulipas for planting the seeds that would develop into the multidisciplinary approach he would adopt for much of his subsequent career.

Behind the Photograph: “A Good Maine Dinner”

Contributed by Emma Lavoie

Warren K. Moorehead and crew in camp, Penobscot River, Maine, 1912. Photograph by Charles A. Perkins. Robert S. Peabody Institute of Archaeology, Photograph Collection

Ever wonder what lies behind a photograph? Beyond the simple description scrawled on the back of each image? The Peabody collection contains more than 600,000 artifacts, photographs, and documents. The Peabody’s photograph collection, specifically, is extensive and contains many interesting, yet untold stories. To bring these stories and photographs to light, we would like to share them with YOU, fellow readers, in our blog series, Behind the Photograph. You can find these stories using our BehindThePhoto tag on our blog.

The year is 1912, the site is an expedition campsite located along the Penobscot River in Maine. On the right a crew member sits on the ground with his back to the camera, legs stretched out in front of him, ankles crossed, balancing his dinner on his lap. Near the tent we see three individuals close together. One sitting through the smoky haze of the campfire, another standing with his plate in his hands – last to get his meal or maybe in line for seconds? An apron on the third individual identifies the camp cook. To the left two individuals sit on tree stumps with dinner plates on their laps, enjoying “a good Maine dinner,” as the title of this photograph describes. The individual in black, farthest to the left, is none other than Warren K. Moorehead, the Peabody’s first curator and Peabody director from 1924 to 1938.

Warren K. Moorehead and Maine Expeditions

During this decade, Maine was a popular destination for archaeological field projects sponsored by the Peabody (known then as the Archaeology Department at Phillips Academy Andover.) Warren K. Moorehead’s first expedition to Maine was organized in 1912. The camping image above was taken along the Penobscot River during this expedition. This venture was so successful that Moorehead sent both survey and excavation crews to Maine each summer for the next three years. During this period, crews surveyed a large portion of Maine’s rivers and excavated dozens of sites. Maine remained the primary destination for the Peabody’s field projects for the remainder of this decade. Although Moorehead’s archaeological interests were focused elsewhere after 1920, he continued to send crews to Maine as late as 1926.

Glass Plate Negative

Much of the Peabody photographic collection is fragile. The Maine expeditions took place at a time when photography, as well as archaeology, was undergoing radical change. With the introduction of smaller and less expensive film cameras, the large and cumbersome view cameras with glass plate negatives were quickly replaced. This transition is reflected in the Moorehead photographic collection.

This image is one of 130 glass plate negatives in the Moorehead photographic collection at the Peabody. Most of these glass plate negatives (including this image) are 5 x 7” in size and appear to have been taken with a Rochester Optical Company, New Model (1890) view camera.  There are a few larger negatives in the Peabody’s photographic collection that are about 6 x 8” in size that were taken with an Improved Model Seneca view camera (1906). The Seneca view camera is still located at the Peabody to this day!

1906 Improved Model Seneca view camera at the Peabody

For further reading about Warren K. Moorehead and his archaeological excavations in Maine check out Warren K. Moorehead’s text, The Archaeology of Maine.

Petroglyph National Monument

Contributed by Ryan Wheeler

This summer included a family vacation to parts of Arizona and New Mexico. That meant a drive and some short hikes in Petrified Forest National Park and the Painted Desert, as well as time in Albuquerque and Santa Fe and points in between. Unfortunately, COVID preempted our attendance at the Santa Fe Indian Market, but we are already planning a short visit next summer!

Image of human hand petroglyphs carved on dark volcanic rock at Petroglyph National Monument, New Mexico.
Petroglyphs at Piedras Marcados Canyon, part of Petroglyph National Monument, Albuquerque, New Mexico. Photo by Ryan Wheeler, April 12, 2019.

Petroglyph National Monument is one of the places that I was looking forward to revisiting with my family. Most of the petroglyphs here were made by Native Americans, but there are some added by the Spanish, cowboys, or other visitors. I had a chance to make a visit during the Society for American Archaeology’s annual meeting in 2019, but at that time I had only went to the interpretive center (no actual petroglyphs there, but a great introductory film) and one of the canyons with petroglyphs—Piedras Marcadas, literally “marked stones.” According to the National Park Service, there are about 400 petroglyphs visible at Piedras Marcadas, but that’s only one of three separate locales within the monument. What struck me most during that 2019 visit was the proximity to suburban Albuquerque. The canyon is literally in the backyard of a residential neighborhood! What we learned during our recent visit was that community activism in the 1980s had helped save the petroglyphs and create the monument in 1990—not all that long ago.

View of Albuquerque from Boca Negra Canyon, August 2022.

This summer we decided to visit Rinconada Canyon, which is only about a mile from the Petroglyph National Monument interpretive center. The park service says you can see about 300 petroglyphs at Rinconada. Despite being right off Unser Boulevard, this site doesn’t have a residential development right next door, so it feels a little bit wilder. The loop trail took us past the canyon wall, which is littered with volcanic boulders. The boulders have a desert varnish of blacks and dark browns, making a good surface for the inscribed petroglyphs that expose the lighter colored rock below the surface. One of the most interesting parts of the monument is the decision not to interpret the meanings of the glyphs, though you can learn a little about this from Native Americans interviewed in the interpretive center film. We went early enough that we didn’t get baked.

Macaw and geometric petroglyphs, Boca Negra Canyon, August 2022.

On a bit of a whim, we decided to visit Boca Negra Canyon, the third petroglyph site in the monument. While apparently only having 100 or so petroglyphs that can be viewed by visitors, this was really the most spectacular of the three locales. At Boca Negra you climb up the mesa and really have an opportunity to get close to the petroglyphs. It’s a little more up and down of a hike, but worth it for the views and the chance to see the petroglyphs close up. The geology of the area is fascinating too. The inscribed boulders are the product of a volcanic eruption around 130,000 years ago. Magma poured out of vents and fissures in the area, creating a sheet of basaltic rock over the softer Santa Fe Formation. The softer sediments on which the volcanic rocks were deposited slowly eroded away, leaving the broken boulders.

Petroglyphs at Rinconada Canyon, August 2022.

The petroglyphs at all three monument locations were made by ancestors of the modern Pueblo people, dating between 400 and 700 years ago, though some are much older. The petroglyphs have been dated based on weathering, but also variations in style and content. There are birds, insects, animals, hands, humanoids, spirals, and other geometric forms. The petroglyphs remain culturally significant to Pueblo people and other Native Americans in the region.