50 
Geological Summary. 
Among the fifty-nine sj)ecies of fossils already described thirty appear 
to me to be new to science, and eight can only he determined with some 
uncertainty, owing to the imperfect state of preservation of the specimens 
submitted to me for examination. 
However, it must he noticed that the new species all belong to genera 
represented in Europe or America by very closely related species, with which 
I have taken care to compare them, and with reference to which I have 
discussed the analogy and pointed out the points of difference. 
As all the species already known belong to the Uj)per Silurian, it may 
he inferred without fear of error that the forms accompanying them came 
into existence during the same period, and that the Australian Eauna of that 
time shows no appreciable difference in forms and size to those of the same 
age in other parts of the World. 
It may also he added that in Australia, as elsewhere, the Ui)per Silurian 
Epoch has given birth to numerous more or less well-marked beds, of which 
those at the base are composed mainly of argillaceous rocks, more or less 
compact and sometimes schistose, corresponding to the Upper Llandovery, the 
most characteristic fossils of which it contains, while the uppermost bed, 
representing the Ludlow, is made up of very hard quartzites, usually coloured 
red by oxide of iron and of white or grey crystalline limestone. 
The different species are distributed in the following manner : — 
Ludlow Group. 
1. Stromatopora striatella, d’Orb. 
2. Ptycopliyllum patellatum, Schl. 
3. Cystipliyllum silurense, Lonsd. 
4. Omphyma Murcliisoni, M. Edw. and J. II. 
5. Cyatliophyllum arfciculatum, Walil. 
6. Halysites escharo'ides, Lamk. 
7. Monticulipora pulchella, M. Edw. and J. H. 
8. Alveolites repens, Eougt. 
9. „ rapa, De Kon. , 
10. Eavosites cristata, Blumenb. 
11. ,, Eorbesi, M. Edw. and J. H. 
12. „ aspera, d’Orb. 
Llandovery Group. 
1. Spiropbyton (?) cauda PhasianI, De Kon. 
2. Rhizopbyllum (?) interpunctatum, De Kon. 
3. Strombodes difflnens, M. Edw. and J. H. 
4. Striatopora australica, De Kon. 
5. Aulopora fasciculata, De Kon. 
6. Syringopora serpens (?), Linn. 
7. Monticulipora (?) Bowerbanki, M. Edw. 
and J. H. 
8. Leptsena quinquecostata, McCoy. 
9. Stropbomenes pecten, Linn. 
10. „ filosa (?), Sow. 
11. ,, coiupressa, Sow. 
