OF NEW SOUTH WALES. 31 



Among the corals we have unquestionable Silurian species, 

 Favosites Gothlanclica, F. asper, Heliolites inter stmctus. 



The occurrence of hollow encrinital stems, a lower Silurian 

 type, gives additional weight to evidence in favour of one portion 

 at least being the equivalent of the lower portion of the upper 

 Silurian. . 



The presence of Galceola and Atrypa desquamata cannot be 

 considered to outweigh the evidence drawn from the mass of 

 Silurian species among which they are found. Their presence 

 there is not so remarkable as was the finding, in Bphemia, in the 

 midst of Silurian species, of large-sized Goniatites, supposed 

 before to be no older than Devonian. 



To these reasons I will add, that in the limestone of the 

 Murrumbidgee, which in places is crowded with many plaited 

 broad winged Spirifers, I have found Spirifer Yassensis, Leptoena 

 suhaequicostata, Loxonema anglicum, Niso Darwinii, species 

 determined by Professor Koninck from specimens forwarded to 

 him by the Rev. W. B. Clarke, to be established Devoniam fossils ; 

 but I have not found a sign of a trilobite nor one shell common 

 to both the Murrumbidgee limestone, and to the Yass and Hume 

 beds. I will not conclude without some reference to the igneous 

 rocks. They are all chiefly Porphyry, some very like Syenite, 

 and presenting on the hill tops a very granitic arrangement 

 of boulders. Other varieties are numerous, some with a pink 

 felspathic base, and several with rather large crystals of felspar 



neighbourhood of Yass, but which are certainly not to be found in the 

 Yass or Hume beds. They will all, I have no doubt, be found where I 

 found those marked with an asterisk (*), that is on the Murrumbidgee, in 

 beds overlying uncomformably the Yass and Hume series. 



Disc'ma Alleglianla OrtJioceras suhdiminuatum i 



Chonetes Hardrensis Murclusonia Turris 



Leptcena nohilis Murchisonia VernuUana 



Rhynchonella Pleurodoii Murchisonia Grani/era 

 Spiri/er multipUcatus Bellerophon convolutus 



Spirifer Cabedensis Pleurotomaria Suhconica 



Spirifer Lalisinuatus * Leptcena Suhcequicostata 



Mitchella Striatula * Spirifer Yassensis 



Nutica Cirriformis * Loxonema anglicum 



Cystoceras Woodsii * Niso Darwinii. 



