Złoty Las (Golden Forest) is the name given to a part of an upland adjacent to the Kaczawa valley in the northern part of the Kaczawskie Foothills, between the settlements of Krzeniów and Jerzmanice-Zdrój. It is known for the occurrence of placer deposits containing gold. The gold-bearing area on the eastern bank of the river is 1.5 km long and covers some 70 ha, lying from 15 to 45 m above the present-day valley floor. Its smaller counterpart occurs on the western bank. The area is also known under the name of Zakonny Las (Monastic Forest), alluding to the fact that for some time it was the property of Franciscan monastery from Złotoryja. The occurrence of gold is connected with sand and gravel deposits laid down by the predecessor of the contemporary Kaczawa river, prior to the advance of Scandinavian ice sheet. Since glacial deposits at the surface did not contain gold, it was necessary to remove the overburden to reach more promising geological layers. Apart from stripping the surface materials, shallow shafts and adits were dug. As a result, the area is heavily modified and anthropogenic landforms are abundant. They include sinkholes and irregular hollows marking the location of collapsed shafts and surface pits, as well as linear gullies which developed by erosion along former transport routes. Gold mining commenced in the medieval times, whereas the last attempt was undertaken in the 1920s, when the Saint Hedwig adit was excavated on the left bank of the river.