Why High-Level Erratics Matter: A TL;DR Summary

The theory that Stonehenge’s bluestones were transported from the Preseli Hills in Wales to Salisbury Plain by glaciers hinges on the presence of high-level erratics. Here’s why they’re critical.

1. Bluestone Appearance: Erratics or Quarried?

Some bluestones resemble naturally weathered erratics rather than deliberately quarried stones. However, whether the stones were naturally collected or quarried in Wales does not impact the glacial transport theory’s validity. The key question is how they reached Salisbury Plain, not their initial state.

Map of the proposed Irish Sea Ice Stream pathway towards Salisbury Plain, 

showing claimed south and east coast high level erratic areas.

2. Lack of Geological Evidence

For glaciers to have carried bluestones from the Bristol Channel to Salisbury Plain, a massive ice flow would have been required. Such an ice flow should have left clear geological traces, like moraines or high-level erratics—rocks naturally deposited at high elevations, far from their source. Erratics found near sea level along the coast don’t qualify, as they could result from other processes. Despite extensive study, no high-level erratics from the Bristol Channel direction have been found in Somerset, Devon or Wiltshire, and the only potential erratics are the bluestones at Stonehenge itself. This absence of evidence strongly undermines the glacial transport theory.

Conclusion

High-level erratics are crucial to validating the glacial transport theory. Without them, or any other geological evidence, the idea that glaciers moved the bluestones to Stonehenge lacks any factual support, making human transport the logical default explanation.

The full study: https://www.sarsen.org/2025/04/analysis-of-claims-regarding-high-level.html