Palaeontologie. 269 
Turning to the Cycadophyta, the author briefly reviews the 
Cycadeae and Bennettiteae , the latter, in comparison with the former, 
highly modified as regards their reproductive Organs. 
The Interpretation of the Bennettitean cone arrived at is as fol- 
lows. Looked at broadly and having regard to the pteridospermous 
affinities of the Bennettiteae this cone is essentially a hermaphrodite 
flower. To take the other view and read a ‘cyathium’ into its struc- 
ture is to verge on the gratuitous. Regarded as a flower we see in 
it a remarkable combination of primitive and advanced characters. 
The microsporophylls of Cycadeoidea, if combined in one plant with 
the seed-scales of Cycas, would give us all the essentials of a quite 
generalised Pteridosperm. 
The great interest and value of the flower of Cycadeoidea seems 
to be that, while it just misses being an Angiosperm, it shows how 
close the Cycad line comes to realising it. It is the key to the Angio- 
sperms; when that is recognised the rest is easy. 
The author provisionally suggests that the two series of Cyca- 
dophytes may be termed Gymnocycad, and Angiocycad respectively. 
Arber (Cambridge). 
Potonie, H., On the Origin of Coal. (Rep. Brit. Assoc. York 
(1906) p. 748—749. 1907.) 
Three kinds of coal, — bright coal, dull coal, and strata coal — 
are distinguished, all connected by transitional stages. If we include 
the recent combustible biolithes, which have certain characteristics 
of coal, there are also three classes, first the peat, secondly the 
sapropel and saprokoll, and thirdly the strata peat. 
Sapropel is formed from the excrements and bodies of comple- 
tely aquatic animals and from plants, which have lived in stagnant 
water, and do not decay completely. Sapropel is a slime or mud, 
and becomes Saprokoll, a gelatinous substance, when subfossilized. 
The Saprokoll of Tertiaryr rocks may be gelatinous, but that of the 
older rocks is very hard. Cannel coal is a lossil Sapropel. Genuine 
coal is fossil peat. The under clays of the coal measures correspond 
to the soils with roots, rootlets and rhizomes, found under modern 
peat seams. 
The strata peat is formed in places which are periodically under 
water. This produces Sapropel, which is again covered with peat 
when the water disappears. 
Coal corresponding to strata peat is very common. The chemistrv 
of bright coal is very different from that of dull coal. 
Whitby jet is wood transformed into sapropelit — to the sapro- 
pelits belong also the bituminious limestones and clays — which 
eventually becomes jet. 
As generally peat is terrestial and sapropel aquatic, both being 
autochthonous, so the bright coal and the dull coal have the same 
genesis. _ Arber (Cambridge). 
Seott, D. H., The Flowering Plants of the Mesozoic Age, in 
the Light of recent Discoveries. (Journ. Roy. Microsc. Soc. 
1907, p. 129-141. PI. VI—IX; see also'Nature Vol. 76, N°. 1961, 
p. 113—117 with 3 figures, May 1907.) 
One of the results of recent discoveries in Fossil Botany has 
been to Show that the seed-bearing and fiower-bearing plants are 
quite distinct. The former occur in Palaeozoic times, while the latter 
