SEDIMENTARY ROCKS OF THE LOWER SHOALHAVEN RIVER. 329 
was not stout enough to resist fracture, and immediately 
on death the shell became broken. Asin the conglomerates, 
deposits of alunogen are found in the rock shelters, also 
stalactites both of limonite and calcite and some earthy 
oxide of manganese. 
(b) The Sandstones of Grassy Gully.—These are really 
an eastern extension of the previous formation, but on 
account of their nature and their fossil contents, they are 
here considered separately. They are found resting directly 
on the Devonian rhyolites on both sides of Grassy Gully. 
Both the freshwater beds and conglomerates are absent. 
From this it is evident that the sea here abutted directly 
against the high shores of the island, and no plain existed 
as on the other side. The beds themselves consist of sand- 
stones and grits, but very little conglomerate. In the 
lower beds pebbles of rhyolite are not uncommon, and of a 
similar nature to the local rhyolites. The remarkable 
feature of the beds, however, is the abundance of fossils in 
some horizons; whole masses of rock are entirely composed 
of their remains. Sometimes they are remarkably well 
preserved with the original shell matter intact. Itis note- 
worthy that the fossils found consisted almost entirely of 
brachiopods, of which several species of Spirifers, two 
species of Martiniopsis, Dielasma, Productus, and Stropho- 
losia, were very common. Of the Pelecypods the Pectens 
were commonest, and the other species were those mostly 
allied to Mytilus, suchas Aphanaia and others. The same 
little pelecypod found at Yalwal Creek is abundant, also 
Platyschisma and Mourlonia; several good specimens of 
Conularia were also found. 
Fossils were also collected on the western side of Sugar- 
loaf about the same horizon, and also on its northern side. 
They were similar in character but with Edmondia and 
Meceonia elongata. Goniatites was found on the Shoal- 
