360 Proceedings of the Royal Physical Society. 
XXVII. On Cryptoxylon Forfarense, a New Species of Fossil 
Plant from the Old Red Sandstone. By RoBERT KIDsTON, 
F.R.S.E., F.G.S. [Plates VIII. 1X.] 
(Read 21st April 1897.) 
About two years ago, through the kind permission of 
Sir Archibald Geikie, F.R.S., etc., Director of the Geological 
Survey of Great Britain, I had an opportunity given me of 
examining the Old Red Sandstone plants in the Jermyn 
Street Museum, London, and among them I observed a small 
specimen from Reswallie, Forfar, having its internal structure 
preserved. This was placed in my hands for examination, 
and has revealed a type of structure hitherto unknown. 
CRYPTOXYLON FOoRFARENSE, Kidston. 
[Plates VIII, IX.] 
The fossil consists of a portion of a stem, slightly com- 
pressed, and preserved in silica of a dark colour. It measures 
about 8 inches in circumference, and is shown natural size in 
side view at Fig. 1. 
The outer surface is covered with small, slightly fusiform 
papillze, which correspond to groups of smaller cells to be 
described later. Most probably the stem originally possessed 
an epidermal layer which has now disappeared, but from the 
manner in which the groups of smaller cells become more 
numerous and less in size as they approach the periphery of 
the stem, as shown in the photograph (Fig. 2), one is led to 
infer that little of the outer portion of the stem is wanting, 
and that possibly the outer envelope consisted more of an 
ageregation of the elements of the stem than of a true 
cortex. 
The plant is entirely cellular in structure, but the cells 
are of two sizes, the smaller occurring in groups scattered 
somewhat irregularly, but showing a distinct tendency to 
a concentric arrangement. 
In section, the larger cells forming the ground mass 
are more or less globular or slightly angular from mutual 
