STONE BLINDS AND DRIVELINES REVISITED – BALTIC SEA ‘BLINKERWALL':

Rollins Pass Driveline, Grand County, CO.,1 mi. of fence, 174 pit blinds & 184 cairns, ca. 6,000 - 3,000 BC, Photograph Peter Faris,  25 July 1987.

One interesting facet of the study of geoglyphs is the fact that many of them are connected to hunting in some way. Some are just simple hunting blinds where the hunter can be concealed while waiting for prey. Some are complex traps for prey, and some are meant to influence the movement of the animals in such a way that benefits a waiting hunter. This last seems to be the case for the recently discovered wall under the Baltic Sea.

Back on 14 February 2015 I published” Stone Blinds and Drivelines – Rollins Pass, CO.” on RockArtBlog, about visiting the vast stone drivelines and hunting blinds on Rollins Pass in the Colorado Rockies with Doctor James Benedict, the noted high mountains archaeologist. Most of the drive lines are now only one or two stones high, any animal could easily step over them, but apparently they are still doing the job today that they were constructed for long ago. “Dr. Benedict stated that one day during one of his recording trips to the site he watched a deer or elk wandering up the slope stop and divert to the side when it came to one of the drive lines, even in their modern broken down and aggraded condition.” (Faris 2015) Apparently their effectiveness depends on the artificial appearance of a straight line in the natural environment. Benedict had estimated that more than a mile of stone walls remain on that location.

3-D model of the west end of the Blinkerwall. Image by Phillipp Hoy, Rostock University, Rostock, Germany.

Now, in 2021, such a construction has been located under the Baltic Sea dating back to before the rise in sea levels at the end of the glaciations period, estimated to be roughly 11,000 years ago there.

“In 2021, Jacob Geersen, a geophysicist with the Leibniz Institute for Baltic Sea Research in the German port town of Warnemünde, took his students on a training exercise along the Baltic coast. They used a multibeam sonar system to map the seafloor about 6.2 miles (10 kilometers) offshore. Analyzing the resulting images back in the lab, Geersen noticed a strange structure that did not seem like it would have occurred naturally. Further investigation led to the conclusion that this was a manmade megastructure built some 11,000 years ago to channel reindeer herds as a hunting strategy. Dubbed the "Blinkerwall," it's quite possibly the oldest such megastructure yet discovered, according to a new paper published in the Proceedings of the National Academy of Sciences—although precisely dating these kinds of archaeological structures is notoriously challenging.” (Ouellette 2024) The assumption is that it functioned with the local reindeer exactly like Dr. Benedict (above) related for the Rollins Pass drive lines. The reindeer would divert and follow the fence to a location where the hunters waited in ambush.

The Blinkerwall, the oldest structure in the Baltic Sea. Illustration by Michal Grabowski.

“The discovery is made up of more than 1,300 stones and roughly 300 larger boulders, and it stretches for more than half a mile along the seafloor. Resting nearly 70 feet underwater in the Bay of Mecklenburg, the wall stands, on average, about 1.5 feet tall. Natural events, such as glacial deposits or other land movements, cannot account for this structure’s existence, researchers report in a study published Monday in Proceedings of the National Academy of Sciences. Instead, they argue, the roughly 11,000-year-old wall was a tool built by hunters to guide and trap reindeer, which tend to travel along straight elements of the landscape, such as cliff sides or streams. ‘Hunters tapped into the natural behavior of the animals and created their own linear feature,’ Ashley Lemke, an underwater archaeologist at the University of Wisconsin-Milwaukee who was not involved with the research, tells Science’s Andrew Curry. ‘It’s not an obstruction, it’s a trail. They follow it to where the hunters are waiting.” (Thorsberg 2024) This preceding description is a very good explanation of how and why such drivelines work.

Scan of the west end of the Blinkerwall.

"'At this time, the entire population across northern Europe was likely below 5,000 people. One of their main food sources were herds of reindeer, which migrated seasonally through the sparsely vegetated post-glacial landscape. The wall was probably used to guide the reindeer into a bottlenick between the adjacent lakeshore and the wall, or even into the lake, where the Stone Age hunters could kill them more easily with their weapons,' explains Marcel Bradtmoller from the University of Rostock. The last reindeer herds vanished from these regions approximately 11,000 years ago due to climate warming and forest expansion. Consequently, the stone wall was probably not constructed after this period. If this is accurate, it would classify the wall as the oldest human-made structure ever found in the Baltic Sea." (Waters 2024)

The animals are diverted along the construction by its very existence on the site, ending up exactly where the waiting hunters want them to be for maximum advantage in harvesting game. Since reindeer migrate in large groups the harvest could have been quite large, illustrating the effectiveness of such a tactic.

Detailed structure of the Bay of Mecklenburg including the location of the Blinkerwall. Bathymetric data from The Federal Maritime and Hydrographic Agency Bundesamt für Seeschifffahrt und Hydrographie (BSH).

The only other possible explanation for this wall (other than it being a drive line) was what the authors (Geersen et al.) call ‘stone fishing.’ “In the absence of basal complexes and basement rocks in Northern Germany, glacially derived stones were used for construction purposes in this area toward the end of the last millennium. The demand for stones resulted in the birth of stone fishing as a profession. Stone fishing represents an anthropogenic effort to move and conquer boulders from the marine environment using stone pincers and ropes. -  After 1906, stone fishing was prohibited, and the stones were left in place being identified as important habitat and also useful for coastal protection. Because stone fishing (had) concentrated on the near-coastal waters and was not done in the central basins, we consider an anthropogenic movement of the stones for the purpose of stone fishing an unlikely candidate to explain the construction of the Blinkerwall. Furthermore, it seems unlikely that within the 18^th and 19^th century, stone fishers would have been able to place the stones next to each other over a distance of about 1 km given the water depth of about 21 m. Let alone the fact that their intention was to remove the stones rather than place them elsewhere on the seafloor.” (Geersen et al. 2024)

So, logically, the fact that the wall is now under 21 meters of water and that it was constructed by humans, the most likely explanation for it is that it was constructed when that area was still dry land, which dates it to the end of the last Ice Age. A very impressive accomplishment for people back then, and an impressive job of deduction for the authors (Geersen et al. 2024) of the report.

NOTE 1: Some images in this posting were retrieved from the internet with a search for public domain photographs. If any of these images are not intended to be public domain, I apologize, and will happily provide the picture credits if the owner will contact me with them.

NOTE 2: I have not included secondary citations in the References (below). For further information on these reports and all sources you should read the original reports at the sites listed below.

 

REFERENCES:

Faris, Peter, 2015, Stone Blinds and Drivelines – Rollins Pass, CO., 14 February 2015, https://rockartblog.blogspot.com.

Geersen, Jacob, Marcel Bradtmoller, Jens Schneider von Deimling and Harald Lubke, 2024, A submerged Stone Age hunting architecture from the Western Baltic Sea, 12February 2024, PNAS, Vol. 121, No. 8, https://www.pnas.org. DOI.org/10.1073/pnas.231008121. Accessed online 20 May 2024.

Ouellette, Jennifer, 2024, Scientists found a Stone Age megastructure submerged in the Baltic Sea, 14 February 2024. Proceedings of the National Academy of Sciences 2024, DOI: 10.1073/pnas.2312008121, https://arstechnica.com. Accessed online 17 February 2024.

Thorsberg, Christian, 2024, Stone Age Wall Discovered Beneath the Baltic Sea Helped Early Hunters Trap Reindeer, 13 February 2024, https://www.smithsonianmag.com. Accessed online 17 February 2024.

Waters, Conny, 2024, Underwater Drone Images Reveal Oldest Human-Made Structure In The Baltic Sea, 13 February 2024, https://ancientpages.com. Accessed online 14 February 2024.