Orthocerový lůmek, Natural monument in Lochkov, Czech Republic.

Orthocerovy Quarry is a protected natural monument in Lochkov with exposed limestone containing Silurian rock layers. The site displays numerous fossils of ancient marine life, particularly cephalopods and other sea creatures from hundreds of millions of years ago.

The quarry was declared a natural monument to protect the reference geological profile for the international stratotype of the Ludlow-Přídol boundary (Upper Silurian). The site is also a rich fossil deposit, notably of cephalopods of the genus Orthoceras, which gave the monument its name.

The quarry is a place where geologists and nature enthusiasts study the layers of the past and understand how the landscape formed. The exposed rock walls tell the story of ancient seas that once covered this land.

The quarry is accessible from the village of Lochkov near Prague and can be viewed on foot from nearby roads. Visit during dry, sunny weather to see the rock layers and fossils most clearly against the exposed walls.

Among the specially protected plants recorded here are Anthericum liliago, the branching lily, and Centaurea triumfettii, the mountain cornflower, both found in the shrubby growth of hazel, privet and cotoneaster. The quarry is small and lies close to the Radotín cement plant, so its fauna is considered unimportant.