in the Protozoic Rocks of New South Wales. 3 
One species of those in Captain King’s possession is very near 
A. Powisii of Murchison’s “Silurian System,” (23, fig. 8.) 
In the course of tny examination of the rocks along the Allyn 
River, I found also in January, 1845, on a hill of some conside- 
derable elevation, called Borrumbat, near Cum yr Allyn, (the seat 
of Charles Boydell, Esq.) where bauds of the Burragood shale 
alternate with limestone and siliceous rock, all of which are charged 
with numerous fossils oCSilurian aspect, Trilobites in some abun¬ 
dance, but of different species from those at Burragood. The 
rocks of Borrumbat pass into rather thick-bedded limestone at 
Binjabury Creek, near Lewin’s Brook, a feeder of the Allyn; and 
in them I found other fragmentary remains of Trilobites. One or 
two species I also met with in the limestone bands near the 
Rouchel River, and on the Brushy Mountain, at Segenhoe, on the 
river Page, in the Upper Hunter district; and some traces of 
Trilobites in a siliceous rock allied with the others, and apparently 
identical with that of Borrumbat, near the Karu River, in the dis¬ 
trict of Port Stephens. The existence ofTrilobites in New South 
Wales, in great abundance it may be said, has, therefore, been 
fully determined ; and I do not doubt that, when other localities 
where the analogous rocks occur, and which are very numerous, 
shall have been searched, many other species of Trilobites will 
come to light. 
Although not necessarily connected with the immediate pur¬ 
pose of this communication, I cannot refrain from alluding to the 
singular fact, that in many instances the most abundant fossils 
are found in the districts above mentioned in siliceous rock, which 
in some cases is a nearly pure Quartzite. Such is the case at 
Borrumbat and at Colocolo, where Turbinolopsis is an abundant 
genus, and other fossils of true Silurian types occur. In the 
neighbourhood of Yass the limestone beds contain corals, some of 
which (StrombodespZicafrm, S.S. 16 bis. 4) are identical with spe¬ 
cies in the Wenlock Rocks of Shropshire. Yet even near Yass sili¬ 
ceous beds occur, equally charged with fossils. James Macarthur, 
Esq., jun., of Arthursleigh, in the county of Argyle, lately gave 
me a Porites of considerable elegance, near to P. pyriformis, 
(S.S. 16.2) from the neighbourhood of Yass. Its matrix is quartz 
b 2 
