150 
DR. HOOKER AND MR. BINNEY ON TRIGONOCARPONS 
these nodules being sealed masses of fossil vegetable remains, and as such are pro- 
bably fair samples of the vegetation that has produced the surrounding coal. The 
immediate cause of the calcification was no doubt due to the abundance of fossil 
shells in the shales immediately overlying the coal and nodules. 
The remains of fossil plants hitherto met with comprise the following genera, 
which are given in the order of relative abundance in which they occurred, viz. 
Calaniodendron, Halonia, Sigillaria, Lepidodendron, Stigmaria, Trigonocarpon, Ana- 
bathra, Lycopodites, Lepidostrohus, Medullosa, and others that are indeterminable. 
An analysis of a piece of fossil-wood {Calamodendron) taken out of the centre of a 
nodule, has been made for us by Mr. Hermann. 
Carbonate of lime .... 76‘66 
Carbonate of magnesia . . 12‘87 
Sesquioxide of iron .... 4'95 
Sulphate of iron 0'73 
Carbonaceous matter . . . 4’95 
From the above observations, it would appear, that the fossils in question are 
possessed of a double interest ; the geologist recognises in them an association of 
vegetables that certainly prevailed throughout the epoch of the Coal formation, and 
in all probability contributed largely, if not almost exclusively, to the formation of 
that mineral ; whilst the botanist detects in them characters of the greatest value as 
throwing light upon the affinities of the Flora of the period. 
A section of any of these nodules shows a confused mass of decayed and apparently 
decaying vegetable remains ; they present no appearance of these remains having been 
brought together by any mechanical agency ; they appear to be associated together 
just as they fell from the plants that produced them, and to be the rotting remains of 
a redundant and luxuriant vegetation. Fruits of Trigonocarpon, entire or more or less 
decayed, occur abundantly, in the masses, along with the stems and roots of ferns and 
other cryptogamic plants and isolated masses of wood of unknown affinity. Lepido- 
strohi of various sizes, and apparently in all states of growth, are intermingled with 
these ; but we have found no traces of coniferous wood, nor of the fronds of ferns ; the 
absence of the latter may readily be accounted for from the fact of the nodules never 
cleaving so as to expose flat surfaces of any of the vegetables, and it is difficult to 
conceive the delicate fronds of ferns so preserved, that their structure should be 
recognized on a transverse section of them in a fossil state. The absence of coniferous 
wood is not so easily accounted for; and coupled with it we may remark, that we 
have not hitherto found any tissue at all resembling that which occurs occasionally 
abundantly in bituminous coal, and is known as mineral charcoal and mother-coal. 
In none of the extensive series of sections that we have made and examined is 
there any appearance of that longitudinal arrangement of the mineral matter tra- 
versed by parallel canals of amber-coloured deposit that is so conspicuous in many 
good bituminous coals, and which has been considered by some eminent micro- 
