122 THE MEDALS OF OREATION. Cuap. VI. 
Indies, and the Moluccas. One leaf was four feet wide, and 
the leaflets, though imperfect, were eighteen inches long.* 
Many other genera of fossil ferns have been established 
from the form and venation of the leaves, and are described 
in Brit. Foss. Flor., and other British and foreign works. 
STEMS OF ARBORESCENT FErns. — Notwithstanding the 
profusion with which the foliage of many kinds of ferns is 
distributed throughout the coal formation, the undoubted 
stems of plants of this family are rarely met with; for the 
numerous tribe called Sigillarve is now removed altogether 
from this class. It may, however, admit of question whether 
much of the foliage which, from the analogy of structure, 
has been referred to ferns, may not have belonged to those 
trees ; for as in the animal kingdom, so in the vegetable, 
distinct types of living organisms are often found blended 
in the lost races ; and as the stems of recent tree-ferns are 
even more durable than their leaves, it seems impossible to 
account for their absence in strata, that inclose entire layers 
of the foliage matted together. A few fossils, supposed to 
possess the essential characters of recent fern-stems, have 
been discovered, and arranged under the following genus. 
* Hoer is a little village, situated nearly in the centre of Scania, a 
province in the southern extremity of Sweden. The Chalk forma- 
tion appears in several parts of this district, and Carboniferous 
strata at Hoeganes. To the west of Hoer, there is a range of hills, 
composed of ferruginous grits, micaceous sandstones, clays, and beds ~ 
of quartzose conglomerate. It is in these strata that the ferns and 
other terrestrial plants occur, and no animal remains whatever 
have been found in them; their geological position appears to be 
between the Chalk and the Coal, but on this point nothing positive 
is known. The general analogy of the plants with the group forming 
the Flora of the Wealden, led M. Brongniart to suppose that the depo- 
sits in question belong to that formation; and M. Nillson, of Lund, 
who examined my collection at Brighton, recognized, among some un- 
described plants from Tilgate Forest, forms that he had collected from 
Hoer. See “ Observations sur les Végétaux Fossiles renfermés dans les 
Gres de Hoer en Scanie; par M. Ad. Brongniart.” Ann. Sc. Nat. 1825. 
