Kielniki Quarry

The Olsztyn municipality calls this place an "open book of geology", and it is hard to argue. The disused quarry on Kielniki hill, about 1 km south-east of the castle ruins in Olsztyn near Częstochowa, lays bare the inside of a Jurassic hill: limestone walls with lenses of ancient sponge reefs, faults, sinkholes and the mouth of a cave discovered during quarrying. It is a stop on a geological educational trail and a good addition to a visit to the castle.

History of the quarry

Limestone from Kielniki was mainly burned to produce lime for building, and Olsztyn had several lime kilns. Quarrying stopped in the 1970s to protect nature and because it endangered the nearby castle ruins. What remains is a large, flat-bottomed hollow enclosed on three sides by very steep walls.

Today the quarry is a protected geosite and a tourist attraction. A waymarked trail with information boards, set up on the initiative of the Polish Geological Institute, runs through it. The full trail is about 5 km long and takes around 3 hours.

What to see in the quarry

• Bioherms – lens-shaped structures in the walls, the remains of sponge colonies on the floor of the Jurassic sea.
• Faults – a dense network of tectonic fractures, best seen in the western wall.
• Kielniki Cave – its entrance is at the foot of the highest, western wall. It was discovered in the early 1970s during quarrying, follows a single long fissure and consists of three small chambers formed by collapsed blocks. Flint nodules exposed by water can be seen on its walls.
• Sinkholes on the quarry floor, filled with brick-red sediment known as "terra rossa".
• Blocks with dripstone – large blocks at the foot of the walls carry mushroom-shaped dripstones and flowstone from caves destroyed by quarrying.
• Fossils – mostly brachiopods and sponges, less often crinoids and sea urchins, and occasionally ammonites.

A second cave, Jaskinia Magazyn, lies at the south-eastern foot of the hill. The municipality points to both as examples of underground karst.

The geological trail from Olsztyn

The walk starts at the foot of Castle Hill, at the first board describing the geology of the Kraków-Częstochowa Upland. The trail then heads east past the Ostra Góra group of limestone outcrops and across sandy terraces with views of Góra Cegielnia. According to the regional tourism portal Śląskie Travel, the blue-marked route to the cave has an information board on ulica Kościelna, next to the historic granary.

Tripto tip

• Footwear: the ground is rocky, and you should only enter the cave in comfortable sports shoes. Bring a warm layer in summer, as the cave is cool.
• Safety: do not climb the quarry walls or approach their edges from above.
• Time: an hour is enough for the quarry, while the whole trail with the castle takes about half a day.
• Fossils: look at them on site and leave them for the next visitors.
• Nearby: the castle ruins on Castle Hill in Olsztyn and the wooden granary on ulica Kościelna.