Fig. 7From: A resin nodule in the Cretaceous Garschella Formation from Langer Köchel (Bavaria, S Germany): possible origin and palaeogeographic provenanceCatalytic decarboxylation, dealkylation and aromatization of agathic acid (labdanoid type) due to the impact of elevated pressure as described by Ruzicka and Hosking (1930). Reference: Ursula Baumer and Johann Koller, Doerner InstitutBack to article page