534 ROBERT KIDSTON ON FOSSIL PLANTS 
The former is easily distinguished from the present species by its small 
size and much more delicate structure, and the latter, by the presence of a clear 
border extending past the “ fringe.” 
It has been suggested that the two genera, Crossochorda and Cruziana, 
should be united, as the only generic distinction rests on the presence or 
absence of the clear border extending past the ultimate segments.* 
Several specimens of this plant have been found. 
Position and Locality.—From the Cement-stone group of the Calciferous 
Sandstone series, Liddel Water, near New Castleton, Liddesdale. 
Bythotrephis, Hall. 
Bythotrephis, sp. 
Remarks.—Two specimens of a large Alga, which should probably be placed 
in this genus, occur in Eskdale. 
init 
Both are imperfect, but the better example gives a fair idea of the plant. 
It appears to have possessed a well-marked dichotomous growth. 
The frond measures fully three-quarters of an inch in breadth, immediately 
below the lowest dichotomy shown in the fossil. 
Each dichotomy is accompanied by a slight constriction at the point where 
it takes place. 
The discovery of Alge in Scottish Carboniferous rocks being of rare occur- 
rence, I have inserted a figure of this specimen, natural size, to draw the atten- 
* Schimper and Zittel, Handb. der Paleontologie, Band ii. Lief i. p. 52. 
