342 ON LEPIDODENDRON AND CALAMITES. 
the greatest errors may arise, as they have in the past. For example, 
the systematic position of Elephas primigenius having been clearly 
established, the inference was thought legitimate that, as the modern ` 
representatives of the genus were confined to tropical or subtropical 
countries, the boreal regions must have enjoyed a similar climate when 
they were inhabited by these ancient elephants. It was, however, dis- 
covered that their skin was clothed with wool and long hair, and that, 
consequently, they were adapted to endure a cold climate. In plants, 
the structure of the fruit would in most cases teach nothing as to the 
temperature and humidity of the atmosphere in which, or the kind of 
soil upon which, the organism grew, though it would be of the first 
importance in determining systematic position. On the other hand, 
the root, the leaves, and the tissues of the plant, would be of only 
secondary importance in regard to systematic position, but of the 
highest value in determining physical condition. In regard to Lepido- 
dendron, its singular roots would seem to imply that it derived a large 
amount of moisture through them from a moist soil, and so far differed 
from most living eryptogamia, which obtain it mostly from the atmo- 
sphere. The roots of this genus presented in their crowded and long 
rootlets an immense surface for the absorption of moisture; and in 
their great abundance of lax cellular tissue possessed the means of con- 
taining this moisture, and transmitting it to the foliage. 
The leaves of Lepidodendron were simple, lanceolate, acute, and ses- 
sile. They had a single medial nerve. The younger branches were 
densely covered with leaves; and the scars left on the trunk after they 
perished, give the numerous beautiful markings by which the species 
have been distinguished. The leaves when found separated from the 
branches, are called Lepidophylia. 
'The fruit was a strobilus (t. 56, f. 3), formed from a shortened 
braneh, the leaves of which are converted into scales, that support on 
their upper surface a single large sporangium (Lepidostrobus, t. 56, 
f. 4), or perhaps several small ones (Flemingites, t. 56, f. 6). There 
appear to be both macrospores (t. 56, f. 5) and microspores in the 
same sporangium. I have examined at length the structure and affi- 
nities of these fruits, in a paper published in the * Geological Magazine,’ 
vol. ii. p. 433, to which I must refer, without here dwelling further on 
the subject. Flemingites, although the sporangia are enormously 
abundant in some coals, have not yet been found connected with any 
