182 
130 fossil species have been found in the coal shale in the 
same area. Dry. Carruthers also tells us that a group of ferns 
has entirely passed away with a stem-structure fundamentally 
different from any now in existence. All these distinctions 
are equally prominent in the still. older Devonian remains. 
So far back as we can trace the three great'groups of Vascular 
Cryptogams they move in parallel and not in converging lines. 
The importance of this fact is so enormous that it seems to 
dispose of the question for ever; for there is really not time | 
enough left before the Devonian beds to allow a primitive © 
cryptogamic form to vary into three such strongly-marked 
and highly-specialised groups of descendants. Then, again, 
as Lyell remarks, it is astonishing how little ferns have 
altered since their first appearance, so that possibly even the 
genus Pteris is a survival from the carboniferous age. If they 
have varied so little during such an enormous period of time, 
why should they be supposed to have varied immensely just 
before the commencement of that time? And is it not a 
singular fact that all the remains which would support the 
theory of the derivation of the three groups from an older form 
have been lost ? 
The same story is told by the other vegetable remains of 
the coal measures: thus the Conifers are represented by 
the Tawinee, or Yew alliance, a highly-specialised form. 
For the present the opponent of the Theory of Descent 
may take up an impregnable position behind his fortress of 
coal. 
9. Do Synthetic Types prove Evolution 2—Synthetic types, 
7.e., those which are supposed to combine the characteristics 
of separate orders or classes, are considered by many as 
a proof of Evolution. Let us bring this assumption to the 
test of fact. I suppose the Cycads are a synthetic type. 
They resemble ferns in the circinate vernation of the leaves 
and in the sorus-like aggregation of pollen-sacs; in their 
dicecious, entirely naked flowers, crowded into cones, they 
_ partly resemble Conifers and partly Equiseta. In the processes 
of germination they resemble the higher Vascular Cryptogams. 
In their general habit they are like Palms. Here, I imagine, 
we have what is usually called a synthetic type. Now, 
according to the Theory of Descent it ought to have been 
prior in time to the Ferns, Conifers, and Palms, the charac- 
teristics of which it combines. As a matter of fact it is later 
than Ferns and Conifers. We ought, according to theory, to 
trace a series of diverging forms starting from it. As a 
matter of fact, we find it an isolated group throughout all its 
existence. Wesee the first scattered indications of its coming 
