112 THE AUSTRALIAN NATURALIST. 
12. The decomposed basalt in one of the fissures 
consists of Kaolin or white clay. 
13. Lhe columnar sandstone constitutes an interest- 
ing feature, alongside of which are reddish outcrops of 
weathered basalt. 
14. The difference in the style of weathering be- 
tween basalt and sandstone are well displayed where 
patches of these rocks are exposed to the action of the 
sea. 
15. Contorted false bedding of sandstone is thought 
to be due to ice action when the beds were ill consoli- 
dated. 
16. Reference to a geological map shows that South 
and North Heads are tombolas or tied islands. 
THE RE-DISCOVERY OF A SAW-FLY. 
By Walter W. Froggatt. 
In his “Natural History of Insects,” Brulle describ- 
eda new Australian Saw-fly (Prerogophorus bifasciatus) 
from Tasmania in 1846. It was a unique type, and was 
unknown in all collections of Australian Hymenoptera. 
About two years ago, Master Harold Brooks send -- 
ing me some entomological specimens from Dungog, 
Tweed River (N.S. Wales), included a section of wood 
full of cocoons, which on examination proved to con- 
tain pupal Saw-flies. Later on a fine series of very 
handsome little Saw-flies with blotched wings, new to 
me, were bred out. 
Considering it a new species, I sent it with other 
insects to the British Museum, to my friend Mr. Roland 
f&. Turner. The ship containing the package (which ° 
fortunately was enclosed in a thick tin covering box), 
was torpedoed in the British Channel, but the mails 
were saved, and finally the package was delivered at the 
British Museum. Though soaked with sea water, the 
little Saw-fly was intact. 
On examination, this proved to be identical with 
Brulle’s long-unknown species described 72 years ago 
from Tasmania. 
