On a ridge at Crousa Common, near St Keverne, stand two prehistoric stones. One remains upright and measures about 1.6 metres high, while the other lies nearby and measures around 2.9 metres long. The upright stone is roughly square in section and has an Ordnance Survey trigger stone at its base. Although modest in appearance, the stones form part of a wider prehistoric landscape with nearby mounds and other scheduled remains. Further upslope, near the summit overlooking Goonhilly Downs, is a small chambered monument known locally as the Three Brothers of Grugith. It consists of two upright stones supporting a capstone and forms a small open ended chamber. The monument measures roughly 4 metres by 2 metres and stands about 1 metre high. The capstone has faint depressions that may be prehistoric cup marks, although their origin remains uncertain. The structure appears to combine natural and built elements. One side of the chamber is formed by a large earthfast boulder, while another upright slab was placed a short distance away. A capstone rests across the two, creating a kist like chamber or stone coffin. Its form suggests possible funerary or ritual use, although no human remains have been recorded from the site. The Three Brothers of Grugith was excavated in 1872 by William Copeland Borlase. He found a pit beneath the capstone and a single flint flake, but no other artefacts. Borlase also noted signs of an earlier pit below the chamber, which may have been a disturbed grave or an earlier feature. These limited finds leave the monument difficult to interpret, but they confirm that the site attracted antiquarian interest and may have formed part of a broader ceremonial landscape. The surrounding area contains naturally scattered stones, but some arcs of stones may represent deliberate arrangements, such as kerbing, a cairn, or part of a larger prehistoric structure. Recent work by Cornwall Council’s Historic Environment Service has focused on mapping and understanding the exposed stones. As scrub clearance and survey work continue, the site may offer further evidence for how natural geology, burial practice, and prehistoric monument building came together on Crousa Common.