SEDIMENTARY ROCKS OF THE LOWER SHOALHAVEN RIVER. 331 
served, and though somewhat difficult to extract, yet 
amply repaid the labour involved. Unfortunately owing 
to rain, I did not have time to thoroughly prospect these 
beds, but nevertheless many good specimens were obtained. 
It is at once noticeable that pelecypods predominate. 
They are in remarkable abundance and variety. Slab after 
slab of sandstone contained nothing else. For the most 
part they were found with both valves complete and with 
the original shell matter preserved. Martiniopsis, so 
common at Grassy Gully, is entirely absent here, while 
Spirifers and other brachiopods were not at all common. 
Several specimens of Zaphrentis were found in one locality 
near Longreach, and near this a band of mudstone with 
Astartila, Platyschisma and other fossils. 
Origin of Wandrawandian Series.—When the Wandra- 
wandian Series as a whole began to be deposited, the 
conglomerates and freshwater beds at Yalwal had just 
disappeared beneath the sea. As mentioned before, the 
shore had by this time retreated away to the south and 
west, and so the beds consisted of finer material which had 
travelled farther. But the sea bottom was not by any 
means stable, and slight elevations continued at various 
times to bring shallower portions above sea level, and 
expose them to the action of the breakers. Thus material 
was obtained, which was consolidated into beds of con- 
glomerate, and these we find interstratified with the 
Kdmondia grits. As we go farther to the eastward, we 
recede from this old shore and the sediments get finer and 
finer, forming the sandstones at Grassy Gully and the 
mudstones at Burrier. The sea was not necessarily deep at 
this stage, but seaward currents must have existed to have 
brought the fossil wood at Burrier so far from land. 
Sub-Division I1I—The Nowra Grits. 
“Nowra Grits’? is the name proposed by Professor 
David for the series of sandstones and grits which underlie 
