443 
having been some species of grain in ear, or perhaps of some small 
cone or strobilus ; but their original mode of existence is best ascer- 
tained from the appearance which is yielded by the specimen figured 
at Fig. 7, where is evidently exhibited the stalk and husks from 
which the grain or seeds have fallen. The width which this spe- 
cimen possesses, making every allowance for compression, will un- 
doubtedly strike you as much greater than that of any known 
vegetable, the grains of which are of no larger size than those which 
are represented at Fig. 6. These seeds, it may be also remarked, 
differ essentially in their disposition from that which takes place in 
the spikes of the grass tribe, having much more the appearance of 
that of the seeds in the strobili of coniferous plants, which seeds 
they also appear to resemble in shape. I am, therefore, of opinion, 
that we must be satisfied with considering these as fossils, whose 
origin must be referred to some hitherto unknown subject of the 
vegetable kingdom. 
M. Jussieu discovered on a stone, which he found at St. Chaumont 
en Lionnois, in the earth, near to the coal, an impression, which, 
he thought, upon close inspection, and comparison with some seeds 
he had received from Pondicherry, bore an exact resemblance to 
the fruit and seed of the Arbor tristis, of travellers, or the Mama 
Pumeram of the Hortus Malabaricus, p. 35, mentioned also by 
Mr. Ray, in his History of Plants, p. 1698. This tree, it appears, 
grows only in the Canaries, at Malabar, on the coast of Coromandel, 
and some other parts of the East Indies*. 
It is a circumstance very difficult of explanation, that silicious 
petrifactions of the roots of plants, or of trees, (^Phitolithi jRadicum, 
RhizolithiJ occur more unfrequently than those of any other parts 
of vegetables which possess a woody hardness. Petrified roots 
are indeed mentioned by some authors ; but are spoken of under 
* Memoire de I’Academie Royale, 1723, p. 69. 
