a2 Thinnfeldia Leaf-Bed of Roseberry Topping. 
cuticles of the upper and lower sides of the leaf, and after 
washing these cuticles should be separated and mounted up 
on a glass microscope-slide in glycerine or canada balsam in 
the usual way. 
On examination under the microscope we shall see clearly 
the polygonal outlines of the epidermal cells which were 
separated by thick straight walls and had a somewhat irregular. 
outline. The cuticle of the upper side is very little thicker 
than that of the lower side, and is uniform in structure, possess- 
ing no stomatal openings. On the lower cuticle however, we 
may observe small groups of six or seven cells slightly raised 
above the general level of the surface, and with a gap or small 
cavity between them. These are the subsidiary cells which 
surrounded a pit at the bottom of which lay the guard cells 
of the stomata. The guard cells themselves were but lightly 
cuticularised, but the slit or stomatal opening between them, 
can frequently be made out. The stomata were not flush with 
the surface of the leaf, as seen in modern ferns and in most 
of the plants around us, but sunken in small pits as seen 
in the pines, cycads, and in many plants living in localities 
which are physically or physiologically dry. 
When compared with the cuticles of other plants, ancient 
and modern, we may notice a somewhat similar structure in 
some of the Carboniferous Pteridosperms, in the Nuilssoniales- 
section of the Jurassic cycad-like fronds, in some recent cycads, 
and some conifers, both of Cretaceous and recent age. The 
circle of affinities is thus narrowed to the pteridosperms, cycads, 
or conifers, among the plants with which we are now familiar. 
Some time ago Prof. Seward suggested that these leaves 
might have belonged to the pteridosperms, a class of plants 
intermediate between the ferns and cycads. The general 
form and insertion of the pinnae favours to some extent the 
cycad view, while a comparison between Thinnfeldia and the 
curious New Zealand conifer Phyllocladus has been made by 
some, including Mr. Antevs, a Swedish paleobotanist, who 
has just published an excellent revision of the genus. The 
question cannot yet be settled, but let us see whether addi- 
tional evidence can be obtained from the study of the remains - 
in the Roseberry bed, for here we have a much larger and more 
complete supply of material than has ever previously been 
obtained. The first point which is noticeble is the vast number 
of Thinnfeldia leaves which go to form this bed, and secondly 
that throughout a thickness of several feet practically no other 
leaves are seen; we do meet with an occasional Nilssonia 
but they are few and far between. We may conclude from this 
that the Thinnfeldia plants formed an almost pure association 
somewhere in the immediate neighbourhood, and that they 
produced a great number of leaves. Now the cycadean plants 
Naturalist, 
