The Fossil Plants. 
157 
selves, is proof, if proof were needed, of the abundance 
of vegetable life. We have a fair knowledge, too, as 
to its variety, but not a single species that flourished 
then survives to-day. 
The ruling forms of vegetation of Mesozoic rocks 
are Cryptogams, Lycopods, Equiseta, Conifers, and 
Cycads. The study, therefore, of Mesozoic plants is 
more restricted than the study of the almost endless 
variety of living plants. The real difficulty with the 
geologist is the finding of plants sufficiently well 
preserved to determine them. Looking at a slab 
of Narrabeen Shale, from the cliffs at Pitt water, 
we find its surface one confused mass of stems, with 
a few indistinct impressions of ferns, but hardly one 
in a perfect state of preservation. There are no 
traces of fruit or flowers ; even in Tertiary rocks we 
seldom have more than leaves preserved. But some 
eminent botanists, who have given themselves up to 
the study of fossil plants, distinguish species and 
genera, with the greatest confidence, from leaves 
alone. As a rule, botanists require the fruit and flower 
for the determination of a plant. The present writer 
collected plants in the interior of this colony for many 
years, having them named by the late Baron Ferdinand 
von Mueller. If by any chance I asked the name 
of a plant of which I only sent leaves and branches, 
the Baron, by a quaint mingling of idioms, invariably 
replied, “By their fruits you shall know them.” 
Geologists, however, have to determine plants mostly 
without flower or fruit. Of course, the leaves of some 
