1847.] CLARKE ON TRILOBITES IN NEW SOUTH WALES. 65 
The characteristic fossils of the mudstone are encrinital stems of 
every variety of form and ornament ; whole masses of the rock are 
made up of these, as if they had been crushed in situ, the longest 
portions seldom exceeding an mch. Next to these are minute 
Atrype and fragments of Polypiaria, the Spirifers being the largest 
fossils. 
At Binjaberri, and for several miles along the ranges dividing the 
Allyn and William’s River, are well-developed expansions of lime- 
stone; and at the head of these rivers, and of the others, such as 
Carrow Creek, Fall Brook, Goorangoola, and the Rouchel, which 
radiate from between the southern spires of the Mount Royal ranges, 
fossiliferous bands and occasional masses of limestone are found in- 
clined around the porphyritic and other igneous rocks that there at- 
tain an elevation of from 2000 to 3000 feet above the sea. These 
masses, at the head of the Williams, are associated with a great de- 
velopment of basaltic rocks which have produced a perfectly prismatic 
arrangement of some of the fossiliferous beds. 
At Lewin’s Brook, at a spot called the Wells, not far from Bin- 
jaberri, a dark schistose and flaggy mudstone is found, at a lower 
level than the beds at Burragood, much-jointed and iron-stained, and 
charged with a variety of very long-winged Spirifers, Productz, and 
other fossils. 
At Colocolo, near Camyrallyn, one of the Spirifers found at Lewin’s 
Brook is alsocommon. The limestone there, as well as at Binjaberri, 
is frequently made up of an infinite number of small globular bodies, 
which do not appear to be distinctly oolitic, but rather resemble some 
new form of encrinital remains. Amidst these well-developed encri- 
nital stems occur, with a vast quantity of Turbinolopsis bina, large 
Fenestellee, Cyathophyllide, Turbinoliz, Atrypze, Orthides (one of 
which is identical with O. semicircularis), Strophomens, Pectens 
and Trilobites, chiefly Asaphi. These fossils are partly coloured by 
yellow and brown oxide of iron, and partly by red. With them I 
found a Fucoid, nearly resembling one figured by Brongniart, and 
some fragments of charred and otherwise metamorphosed vegetable 
matter. . 
Passing now to the southern district of Murray, we find at Yarra- 
lumla rocks of a description similar to those of the Paterson and 
Allyn. The principal fossils in the blocks I have examined are the 
Trilobites mentioned at the beginning of this memoir. Of these I 
have six species. Their remains are as frequent as those of encrinites 
at Burragood. Associated with them is an Orthis, which can hardly, 
if at all, be distinguished from O. orbicularis, and another greatly 
resembling O. semicircularis, the former bemg Devonian as well as 
Silurian. Besides these are species of Fenestellee and Reteporee, and 
extremely minute Atrypz. Leptena sericea also occurs. 
Now at Yass Plains, the limestones of which are connected with 
the limestones and mudstones of Yarralumla, not only are Favosites 
Gothlandica, Amplexus arundinaceus, and an Orthoceratite mentioned 
by Strzelecki, but I have seen Strombodes plicatum amongst the 
Yass fossils. 
VOL. IV.—PART I. F 
