206 SECTIONAL ADDRESSES. 



River district of New South Wales : this section gives the sequence of 

 events antecendent to and during the existence of the Glossopteris ¥1013,. 

 At the base are sediments known as the Burindi series : in some of the 

 beds pieces of drifted Lepidodendron stems were found in company with 

 marine shells. Resting on the Burindi series is the Wallarobba conglo- 

 merate, a mass of pebble beds 1,500 ft. thick, which marks the initial stage 

 of a great upheaval and the beginning of a new geological cycle recorded 

 in strata included in the Kuttung series. In volcanic material immediately 

 above the conglomerate were found petrified stems and petioles of the 

 Lower Carboniferous European and Siberian fern Clepsydropsis, stems of 

 the Gymnosperm Pitys, a common early Carboniferous type in the northern 

 hemisphere, and a petrified Lepidodendron apparently specifically identical 

 with a southern Scottish species. The Kuttung series, approximately 

 10 000 ft. in thickness, furnish an impressive record of a prolonged period 

 of volcanic activity, with recurrent quiescent intervals, when the valleys 

 were occupied by glaciers, which have left traces in beds of boulder clay 

 and erratics dropped from floating ice. Leaves of Rhacopteris and Cardiop- 

 teris and casts of Aster ocalamites, genera characteristic of Lower Carboni- 

 ferous floras, bear witness to the spread of vegetation under a relatively 

 low temperature and in an atmosphere charged with volcanic dust. A well- 

 marked break both in the succession of fossils and in physical conditions 

 is registered in the rocks at the summit of the Kuttung series : this un- 

 conformity is the expression of a crustal disturbance coincident with the 

 appearance of the Glossopteris Flora. The Kuttung series is followed in 

 ascending order by a thick glacial deposit : this forms the base of the 

 Lower Marine Series which includes marine sediments and lava flows : 

 at approximately the middle of the Lower Marine Series were found the 

 t)ldest known Australian examples of Gangamopteris, and from a bed near 

 the base of the series specimens of the bivalve Eurydesma, a genus recorded 

 also from S. Africa and India. Above the Lower Marine series are the 

 Greta Coal Measures containing Gangamopteris and other members of the 

 Glossopteris Flora ; then follows the Upper Marine series, which includes 

 two sets of boulder beds indicative of a return of glacial conditions after a 

 long interval. Glosso]}teris and other plants have been obtained from the 

 overlying Tomago and Newcastle series ; and finally we come to a 

 succession of Triassic sediments known as the Hawkesbury series. 



The problem is to correlate the rocks exposed in the Hunter River 

 section with time-equivalents in the northern hemisphere. The beds 

 below the Lower Marine series, containing the oldest examples of Gangamop- 

 teris, suggest a Lower Carboniferous age. This view is accepted by Prof. 

 Schuchert who, however, regards the break between the Kuttung series 

 and the overlying Lower Marine series as representing the whole of Upper 

 Carboniferous time. He refers the boulder beds and the marine and 

 volcanic rocks of the Lower Marine series to the Permian system. Let us 

 now turn to Western Australia in search of further evidence afforded by 

 marine fossils : there we find a coal-bearing series known as the Collie 

 Coal Measures and regarded as the equivalent of the Newcastle series of 

 New South Wales. In another area, below the Collie Coal Measures, there 

 are glacial deposits resting on the Irwin Coal Measures, the equivalent of 

 the Greta Coal Measures of New South Wales. Beneath the Irwin Coal 



