STROMATOLITES FROM MIDDLE OLD RED SANDSTONE OF WESTERN ORKNEY

The structures are comparable with stromatolites seen in modern “flats” environments and tufa occurring in joints in the granite—gneiss basement is compared with modern and fossil forms. Finely laminated (? varved) carbonates with a large lateral persistency (1: 50,000) are referred to periods of high water level and are believed to show evidence of seasonal algal bloom. The presence of widespread stromatolite structures is consistent with earlier environmental interpretations of the Orkney rocks. © 1969, Cambridge University Press. All rights reserved.