On the island of Hisingen, 17 km to the north of Gothenburg on the west coast of Sweden, a breccia was exposed after removing 3.5 m Quaternary deposits. The breccia occupied two fissures in the Precambrian rocks. The fissures were 0.5 and 3 m wide, respectively, and the observed length approximately 6 m. They struck N 68° W and had a vertical dip. The breccia consisted of big boulders of limestone, stinkstone-concretions, sandstone, and weathered remnants of alum shale. There were also fragments of gneisses and amphibolite. The main part of the breccia material belongs to the Cambrian. The fossil content of the breccia will be treated in a separate paper by Dr. A. Martinsson, Uppsala. The big, unbroken stinkstone-concretions (c. 1 m in diametre) and the big boulders of limestone with preserved bedding indicate a short transport of the material before being deposited in the fissures.