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Geology of Sydney. 
The Newcastle series (Palaeozoic) are always to 
be known by the abundance of the fossil fern called 
Glossopteris, and the Ipswich series by a fern called 
Tceniopteris. It will make things a little clearer to 
anticipate some points of classification, and here note 
what kinds of ferns are those just named. Glossopteris 
is a simple, entire leaf with a mid-rib, and the small 
veins united or netted ; that is to say, joining so as to 
form a reticulated mass. Tceniopteris is a simple, 
entire leaf with a mid-rib, and the smaller veins pro- 
ceed from the mid-rib, at nearly a right angle, towards 
the margin. These veins seldom divide or fork more 
than once, and these branches never unite to form 
a net. 
Glossopteris belongs to the family Dictyopte- 
ridece , a name which explains itself, since diktuon is 
the Greek for a net, and this family is meant to 
include all ferns with a netted venation. Some readers 
may be inclined to ask, — Is this a very natural division V 
or whether, among living ferns, those with netted 
veins stand apart as a peculiar family ? They do 
not ; in fact, netted veins and simple tongue-shaped 
fronds, with a mid-rib, are found in almost every 
family. Botanists are obliged to take what they can 
get as a means of grouping fossil ferns ; and though 
no fault can be found with this, we must bear in mind 
that artificial methods of classification bring together 
very different forms. We give the name of Glossop- 
teris to simple fronds with a costa and netted veins, 
but the same definition would at the present day 
