BY W. X. BKNSOX. 375 



vein, will often be in optical continuity with that in the vein. 

 ►Sometimes, the rock contains only a few of such replacement- 

 areas ('^.^., No. 1408), which are generally rather sharply bounded, 

 but, in other specimens, the whole of the groundmass is replaced 

 (No. lttL'5), and very little indeed of the coloured constituents 

 remain. 



In addition to these ^■eins oi' quartz, there are occasionally [e.g., 

 in No. 138G) to be found veins less than 0-3 nmi. in diameter, which 

 consist of a line-grained mosaic of water-clear albite, which may be 

 associated with a little calcite. 



The brecciated keralophijres Avhicli occur along the eastern mar- 

 gin of the eastern keratophyre zone, have already been sufficiently 

 described {see p. 344). 



No further remarks need be added to the description of the 

 Devonian pyroclastic rocks given in previous papers. A number 

 of peculiar forms of alteration of the rock-fragments in the 

 Nemingha Red Breccia have been noted, but the general conditions 

 attending the development of that formation are now sufficiently 

 well estaldished, and these details are merely confirmatory. 



Notes on the Loombekah Fossils. 



As pointed out above, the fauna of the Loomberah limestone has 

 been found by JNlr. W. S. Dun to contain a number of new and 

 interesting forms, concernmg which he has kindly contributed the 

 following valuable notes, and to these are added further remarks 

 by tlie [)resent author, which are placed between brackets: — 



"This limestone is, in most cases, of detrital origin, and, especi- 

 ally in the ease of the Rugose Corals, the preservation is so unsatis- 

 factory that, although manv^ of the forms are new, the specimens 

 are so imperfect, that it is impossible to obtain sufficient evidence 

 to make the diagnosis proper to a new species." 



"Zaphrentis, sp. ind. — One specimen. The transverse section 

 shows 61 septa, with a dense psendocolumella, and limited stereo- 

 plasma. (See Plate xxxv., fig. 6.) The longitudinal section shows 

 very irregularly placed tabulae strongly concave." 



^^Zaphrentis, (?)sp. — A single specimen of a very interesting 



