W. H. Lang and F. R. S. Barker. 1925. II. Contributions to the study of the Old Red Sandstone flora of Scotland. I. On plant-reamins from the Fish-beds of Cromarty. II. On a sporangium-bearing branch-system from the Stromness beds. Transactions of the Royal Society of Edinburgh 54:253-279 [W. Stein/N. Smith/J. Cassara]