Airpendix. 269 



form it compares most nearly with A. pisijormis, L. sp., and A. 

 piinctiwsus, Angelin. The affinities of the Australian species 

 seem to lie rather with the Cambrian than the Ordovioian forms. 



IProetus sp. nov. Remains of a large and handsome form, 

 with a wide and straight anterior border, long glabella and 

 granulose cheeks, are common in the limestone. The specimens 

 show very marked characters which tend to separate them from 

 species of the genus sen.su, stricto, and their nearest allies seem 

 to be certain Proetids from the Girvan area in Scotland, of 

 Upper Ordovician age, and younger. 



ICheirtirus. The remains of two pygidia show them to have 

 a depressed, but roundly terminated axis, which does not extend 

 to the posterior margin, few segments, and a wide lateral border ; 

 whilst at the posterior angles were stout spines. Vestiges of other 

 detached spinous processes also occur in the matrix. 



But for the presence of the new species of A^i^tiostus, it might 

 be asisumed that the limestiuie was of Upper Ordovician age, 

 takins: into consideration the facts of the association of the beds. 

 The presence of this older form, however, makes it an open 

 question as to the contemporaneity of the limestone and the 

 adjoining slates. It is to be hoped that better and more copious 

 material will be forthcoming from this very interesting district, 

 when these and other forms can be fully described, and inferences 

 dra^^^l with more certain knowledge. 



PLATE XT. 



Sketch Map of the Dolodrook Serpentine Area. 



