Smithsonian Report, 1948.—Holmes PLATE 1 
1. Upper old red sandstone strata (age about 280 million years) resting un- 
conformably on vertical Silurian rocks (about 3820 million years) at Sieccar 
Point, Cockburnspath, Berwickshire. 
Photograph courtesy H. M. Geological Survey, by permission of the Director. 
2. Carboniferous limestone (about 240 million years) resting unconformably on 
inclined Silurian slates (about 320 million years) at Arco Wood Quarry, 4 miles 
north of Settle, Yorkshire. 
Photograph by Prof. 8S. H. Reynolds. 
