mong the large collections relating to natural history which have been brought 
Akon by the Swedish expedition to N. W. Australia in 1910—11, there are also 
some fossil plants of Mesozoic age. They were found in the neighbourhood of Derby, 
West Australia, and are preserved either only as impressions in clay and sandstone 
or as thin films representing the vegetable tissue. These fossils are interesting be- 
cause none of the same kind have hitherto been described from this state, which, 
being the most inhospitable and the least advanced part of Australia, is very little 
known in scientific respects. Certainly, a few fossil plants have been collected in 
Western Australia; but they have been found more or lessin passing and have only 
served for the determination of the age of the strata in question. They have not 
been made the subjects of a methodical research for their own sake. — The plants 
here treated are kept in the Palaeobotanical Department of the State Museum of 
Natural History in Stockholm; and I have been requested to give a short description 
of them. 
Dicroidium Feistmanteli GoTHAN. 
PITotestölq 
1847. Odontopteris microphylla Mc Cor, Ann. Mag. Nat. Hist., vol. 20, p. 147. 
1878. Tlhunnfeldia odontopteroides FEISTMANTEL, pars, Paleontographica. Suppl. 3, Lief. 3, Heft. 3, p. 105, 
pIITi6; DS: 
1879. Tlinnfeldia odontopteroides FEISTMANTEL, pars, Paleontographica. Suppl. 3, Lief. 3, Heft. 4, p. 165, pl. 9 —11. 
1890. Thinnfeldia odontopteroides FEISTMANTEL, pars, Mem. Geol. Surv. N. S. Wales p. 101, pls 23—25; pl. 
20, 0IgS 
1898. Thinnfeldia odontopteroides SHIRLEY, pars, Queensland, Geol. Survey. Bull. 7, p. 21, pl. 10, fig. 2; pl. 11. 
1902. Tluinnfeldia odontopteroides ÅRBER, pars, Quart. Journ. Geol. Soc. vol. 58, p. 2. 
1910. Thinnfeldia odontopteroides SEWARD, pars, Fossil Plants, vol. 2, p. 538, fig. 356 B. 
1912. Dicroidium Feistmanteli GotHAn, Uber die Gattung Thinnfeldia Ett. Naturhist. Gesellschaft Närnberg. 
TOT BArBpsadS, Marie näs 
This species is represented by several specimens, which, though unfortunately 
very fragmentary, agree well enough with those figured by FEISTMANTEL, as the fol- 
lowing description will show. 
The frond is large, bipinnate, but the specimens in question can supply no in- 
formation as to whether the broad rachis has been forked or not. The pinnae are 
long, with rhomboid, ovate or semi-elliptic leaflets, which, towards the end of the 
