86 GEOLOGY OF LOWER MESOZOIC ROCKS OF QUEENSLAND, 



iii. Clarence Series. 



Alethopte7'is australis [Clado- Tceiiiopteris Daitttreei [7\ spa- 



phlebis australis]. tulata\ 



Thinnfeldia odoufopteroidas. T. Tenison- Woodsi. 

 Sphenopteris. 



iv. Artesian Series. 

 Tceniopteris Daintreei [7'. spxt- Thinnfeldia odontopteroides. 

 tulata]. Baiera. 



The plant to which special prominence has been given, in 

 dealing with Australian Lower Mesozoic strata, is TcEuiopleris 

 spatulata [T. Daintreei], This plant is of very widespread oc- 

 currence in Eastern Australia, and seems to be a reliable indi- 

 cator of age. In Queensland, it is found abundantly in the 

 Walloon Series, but not in the Ipswich Series. In New South 

 Wales, it is found in the Clarence Series, Artesian Series, and 

 Talbragar Series, but not in any stage of the Hawkesbury Series. 

 There is no doubt of the identity of both the Clarence and Arte- 

 sian Series with the >A alloon Series, for they are continuous in 

 the tield. The Talbragar Series is unconformable on the Hawkes- 

 bury Sandstone, and the presence of Toiniopteris spatnlata in the 

 Talbragar Series indicates the relation of this Series to the 

 Walloon Series: the occurrence of a Taxites comparable with 

 7\ planus is additional evidence for assigning the two Series to 

 the same period. 



The next point to be considered is the relation of the rocks of 

 the Hawkesbury Series to the other Lower Mesozoic rocks. 

 There is no doubt that the Hawkesbury Sandstone is older than 

 the Talbragar Series, and, therefore, older than the Walloon 

 Series. What then is the relation between the Ipswich Series 

 and the Hawkesbury Series ? In the following Table are in- 

 cluded the species of plants in the stages of the Hawkesbury 

 Series which are identical or closely comparable with species 

 in the Ipswich Series, the allied species in the Ipswich Series 

 being indicated in square brackets. 



