BY W. N. BENSON. 553 



Stroiiiatopora is fairly common, and a form of Ileliolites, that is 

 apparently not porosa, is occasionally present, while a certain 

 species of Try plasma is rather common The other forms are of 

 less stratigraphical importance, and Sanidophyllum, though occa- 

 sionally present, is very rare. The Moore Creek limestone is 

 characterised by the abundance of Sanidophyllum davidis, Spon- 

 yopliyUuin giyanteuni, Actinocystis cornu-hovis^ Syringopora aulo- 

 poroides, Litophylhtvi koaincki, and Heliolites porosa, the last 

 often forming very large masses. All these forms are rare or 

 not developed in the lower limestone. 



The study, b\^ Dr. Hinde, of the radiolaria of the Middle 

 Devonian Series included the description of fifty-three new 

 forms(lO); others still await description. 



The Upper Middle Devonian claystones, but not, so far as is 

 at present known, the Lower Middle Devonian, contain numerous 

 casts of Lepidodendron australe, both in its normal form, and in 

 the /iT^iorria-condition. It may be found especially in Long 

 Gully, and also in Loder's Gully, but is not so abundant here as 

 it is in the Upper Devonian rocks. 



Distrihution of the Lower Middle Devonian Rock<. — Taking 

 the limestone (associated with tuff), the cherty and quartzitic 

 rocks, and the Igneous Zone as the characteristic rock-types of 

 the Lower Middle Devonian Series, let us trace them northwards 

 and southwards from the above-mentioned line of section, to 

 ascertain the structure of our area. The northward-pointing 

 arch of the limestone in the anticline in Seven Mile Creek, is 

 met by another pointing southwards, and very sharply bent. 

 Its two branches are close together, and, traced northwards, 

 appear at intervals all the way to Moore Creek. They form 

 narrow, lenticular patches generally closely associated with pyro- 

 clastic rocks, and frequently completely surrounded by them, or 

 appearing merely as large or small inclusions of limestone in a 

 mass of pyroclastic rock. This passage of a band of limestone 

 into an igneous breccia containing fragments of limestone is a 

 constant feature of this horizon throughout the whole of the 

 Serpentine-Belt, as was pointed out in earlier papers, and is 

 particularly well exhibited in the Nundle District(15). It is also 



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