SearsMill-WesternDiabaseDike-Narrow-500px November 11, 2019 500 × 377 SearsMill-WesternDiabaseDike-Narrow-500px Tree growing out of the diabase boulder outcrop Soils and vegetation eventually break down the diabase boulders. These are in the Jurassic dike indicated on the geological map of the Greenlevel quadrangle as a narrow red line.