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Thornton Quarry

ROCKHOUNDING PERMISSION REQUIRED DOCUMENTED

Where: Illinois · North America · approx. 41.57, -87.61 (vicinity only)

Why this spot: Giant Silurian reef quarry south of Chicago

What turns up: reef corals, brachiopods, trilobite parts

Access: Permission required.

Active quarry; entry only on scheduled club trips.

Open in Mudlark Map →

Satellite view, historic-map overlays, tide/flow context and field notes are in the app. Exact research detail is part of Pro.

Pins are approximate by design. This page is historical research, not permission to dig. Check ownership and local law first.