thumb|300px|right|Cropmarks at a protohistoric site at [[Grézac, France]]
thumb|300px|right|Cropmarks at a protohistoric site at [[Grézac, France]]
Cropmarks or crop marks are a means through which sub-surface archaeological, natural and recent features may be visible from the air or a vantage point on higher ground or a temporary platform. Such marks, along with parch marks, soil marks and frost marks, can reveal buried man-made structures that are not visible from the ground.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).