Anomalous landscapes amid local forest

This is quite something. For some reason known only to geologists, the large forest to northwest of Hipolitów and southeast of Sułkowice contains a hilly ridge running through it. Pines, birches and oak trees dominate the hillsides. The contoured sandy soil is exposed to the elements with several areas each of a couple of thousand square metres appearing to be sand pits.

I visited this fascinating landscape last Wednesday and again this morning, catching a train one stop south to Sułkowice and walking home (on Wednesday I did it the other way around – walked out, train back).

Below: a most unusual sight for this part of Mazovia; I am immediately reminded of Oxshott Heath, a frequent family weekend destination in my childhood, and the forests and dunes around Stella-Plage in northern France.

Below: trekking uphill, suddenly the vista opens up to a vast sand pit.

Below: the second sand bowl, to the northwest, this one popular with the quadricyclist community. Aerial images of this feature show that a lake can form at the bottom; it's now totally dried out without a trace. 

Below: after sunset on Wednesday evening, 25 September, the destination of my equiluxial walk. 

Below: and a few minutes later; dusk descends upon the scene. Through the forest I return to Sułkowice in darkness. It's 3km from here to Sułkowice station; I'm in good time to catch the 19:08 train; three minutes later and I'm back in Chynów.

Below: from geoportal.gov.pl, an orthophotographic map of the area showing the raised land snaking across a flat landscape, with the sand pits gouged out from the hillsides. The question is: were these once commercial excavations of building sand? (The sand pit at Oxshott Heath was originally dug to provide filling for sandbags used in WW1.) 

Below: from Google Earth Pro, satellite imagery from 2011 and 2020. The maps can be aligned with orthophoto above by means of the forest road running southwest to northeast. Note how their shape and size had changed over those nine years.

This time four years ago:
W(h)ither the DK50?

This time five years ago:
A change in the weather

This time six years ago:
Zamek Topacz classic car museum

This time nine years ago:
Curry comes to Jeziorki

This time ten years ago:
Why we should all try to use less gas

This time 11 years ago:
Polish supermarket chain advertises on London buses

This time 16 years ago:
Well-shot pheasants