196 HISTORICAL PALAZZAONTOLOGY. 
deposits of this age with which we are as yet acquainted. Red 
rocks are, as a general rule, more or less completely unfossil- 
iferous, and sediments of this nature are highly characteristic of 
the Permian. Similarly, magnesian limestones are rarely as 
highly charged with organic remains as is the case with normal 
calcareous deposits, especially when they have been subjected 
to concretionary action, as is observable to such a marked ex- , 
tent in the Permian limestones. Nevertheless, much interest 
is attached to the organic remains, as marking a kind of transi- 
tion-period between the Palzeozoic and Mesozoic epochs. 
The plants of the Permian period, as a whole, have a dis- 
tinctly Palzeozoic aspect, and are far more nearly allied to those 
of the Coal-measures than they are to those of the earlier 
Secondary rocks; though the Permian sfectes are mostly dis- 
tinct from the Carboniferous, and there are some new genera. 
Thus, we find species of Lepzdodendron, Calamites, Equisetites, 
Asterophyllites, Annularia, and other highly characteristic 
Carboniferous genera. On the other hand, the Szgz/larioids of 
the Coal seem to have finally disappeared at the close of the 
Carboniferous period. Ferns are abundant in the Permian 
rocks, and belong for the most part to the well-known Carbon- 
iferous genera Alethopteris, Neuropteris, Sphenopterts, and Pecop- 
teris. ‘There are also Tree-ferns referable to the ancient genus 
Psaronius. The Conifers of the Permian period are numerous, 
and belong in part to Carboniferous genera. <A characteristic 
genus, however, is Walchia (fig. 134), distinguished by its lax 
4 Wi Nar 
Loy: 
VY 
pe FF Z 
j 
NULL Lh? 
Fig. 134.—Walchia piniformis, from the Permian of Saxony. 
a, Branch; 6, Twig. (After Gutbier.) 
short leaves. This genus, though not exclusively Permian, is 
mainly so, the best-known species being the W. pinzformis. 
Here, also, we meet with Conifers which produce true cones, 
and which differ, therefore, in an important degree from the 
