ht a. M. JOHNSTON, F.S.S. 



19 



temperature at which they are burned. A rotary kiln, very largely 

 used in America, is a great improvement on the old forms of 

 calciners. 



Yours iaithfuUy, 



W. F. WARD, Government Analyst. 



To the Secretary for Mines, Hohart. 



Appendix B. 



Detailed Description of the Darlington Beds, 

 as described by A. Montgomery, M.A. 



Thickness. 





^ ! 



^5 



^ 



S 

 s 



r*!* 

 ^ 



Ft. 

 320 



30 



43 



2 

 1 



124 



In. 

 



Description of Beds. 



Limestones consisting chiefly of crinoid 

 remains in beds from 6 inches to 4 feet 

 thick, separated by thin slialy partings. 

 This limestone seems very pure, except 

 that it frerpiently contains bunds and 

 masses of chalcedony ( Buhrstone) 

 formed by the infiltration and segre- 

 gation ot siliceous solutions. The beds 

 of the large quarry at B. on plan 

 belong to the lower part of this series. 



Beds of blue hydraulic limestone, 6 

 inches to 4 feet thick, worked in quar- 

 ries at A. C. D. E. and F. on plan, 

 separated by beds of calcareous shale 

 and mudstone, amounting, probably, 

 to nearly half the whole bulk of the 

 beds. The limestones show fossils of 

 aviculopecten, npirtfera, productus, and 

 fenestella in abundance; pachydomus 

 common, but less frequent. Small 

 stones not uncommon 



Shaly limestones, very rich in Spirifera 

 and productas 



Dark shaly mudstone 



Volcanic ash or tuff, very hard, full of 

 small glittering granules of glassy 

 quartz, felspar crystals common, also 

 fragments of various rocks : decom- 

 yjoses to a yellowish-brown clayey 

 stone, which still shows the glassy 

 quartz granules very distinctly 



iMudstones, with but little lime, very rich 

 in species oi fenestella, stenopora^&cQ.,. 



Total 

 Thickness 

 of Strata. 



Ft. 



In. 



608 



288 



258 

 215 



212 



210 



