I'm not very sure about Scandinavian circuits. Google tells me a couple exist in Norway but I don't think they are old enough, so perhaps it's in Denmark. The Wikipedia entry for Roskilde Ring includes this description "Because the track was built in an old gravel pit it looks like an amphitheater" so that's my guess.
Got it in one. Well solved. The Roskilde Ring was built in 1955, as you say in a gravel pit, which explains the more or less oval shape with banked sides. It was a massive 670 metres for a lap, although in 1957 the owners used more land alongside the oval which stretched the length to 1.4km, approx. 0.87 miles.
The Danish motor sport authorities used to hold a pukka Formula 1 race there, surely the shortest circuit ever used for the top echelon cars. Here's Stirling Moss and Jack Brabham in 1961.
