BY W. N. BENSON. 559 



by the small patch of limestone in the keratophyres of portion 

 175 (see p. 57 2). The lenticles of limestone that lie about a 

 quarter of a mile east of this line, in portions 180 and 216, are 

 probably on the horizon of the Loomberah limestone. They are 

 white, crystalline rocks, free from pyroclastic impurities, and all 

 trace of fossils has been lost. East again of these, there is another 

 line of doleritic intrusions, lying along the western side of Spring 

 Creek. These may perhaps be correlated with the Igneous Zone. 

 If so, we may class with the Nemingha horizon the series of lime- 

 stones that occur in the creek-valley, and commence to the 

 north with the large mass of metamorphosed limestone, in por- 

 tions 88, 91, and 118, which is exactly like that described 

 above. This is followed to the south by a series of small lenses 

 of limestone, generally intimately associated with pyroclastic 

 rocks, occurring in portions 126, 216, and 153. At the southern 

 edge of the map in portion 121, is a large lenticular mass of 

 white crystalline limestone, quite free from traces of fossils, about 

 400 yards long and 60 yards wide. This is probably on the 

 same horizon as the limestone that occurred on the boundary of 

 portions 180 and 216, and may tentatively be classed with the 

 Loomberah limestone. The stratigraphy of the southern end of 

 the area mapped is quite indefinite. To complete the tracing of 

 the structure-lines, as far as is possible, one may note that, east 

 of Spring Creek, in portions 113, 119, and 123, is a mass of 

 highly altered dolerite, and other basic rocks, which may repre- 

 sent still another repetition of the Igneous Zone. Further 

 repetitions of the rocks of the Lower Middle Devonian Series 

 occur, as has been noted above, among the rocks of the Woolomin 

 Series, and, together with them, make up the Eastern Series, 

 which lies east of the Serpentine-Belt. 



Distribution of the Upper Middle Devonian Rocks. — This series 

 has been defined as that extending ffom the Igneous Zone, which 

 closes the Lower Middle Devonian, upwards to the Baldwin 

 Agglomerates. It includes the Loomberah and Moore Creek 

 limestones, but, as these occur at opposite ends of the area 

 mapped, their relation to one another is not known. Apart 



