St'ONtJiUMI VM.IM l'l;(i,\l IIIK ri'I'Kl; SIHIUAN I.MiCkS dl' N.S.W. .S7 



pinper (i'l. vii., ti<i-. 2), vi't a<i-aiii at the jiiiictioii of coiititriious 

 coiallites we nee only tlie outer ends of the |)eri})heral vesicles 

 abuttiiisr ayaiTist one another leavin«^ a Hinfjle dark line resembl- 

 ingf a wall ; or, the ends of the vesicles facing one another 

 sejtarated bv a o^iveji s|)ace tilled with stereoplasmic 

 matter similar to that Iiiiin,<>- the general cavities of the 

 coral. This deposit sometimes iindertj^oes a furthei' alteration 

 into clialcedonic matter. In weathered examples the ends of 

 the vesicles are visible without any coverino- whatever. 



To neither of our desci'ibed Australian species (S. liliKtrtitimi, 

 and (S'. (ii<iiiiifi'init) is this nearly related, the various parts are on 

 a far larger scale and the development of tlie septal system 

 is less. It was, at first, very doubtful whether or not to refer the 

 coral to S}>t>iiiii>iiliiiJIin)i, but no more available genus has pre- 

 sented itself. The only species in any way comparible with S. 

 eiiorme in size is N. him f hi, Schliiter^, but even here tlie differ- 

 ences are very mai'ked. The vesicular structure closely 

 I'esembles that of ( hu jih ijuni. 



Liic. Escarpment north-east of Boonoo Ponds Creek, Hat- 

 ton's Cornel', Yass Kiver, near Yass (L'. Eflicriih/r and .1. ./. 



S/ii'iirshij). 



Hiir. — Boonoo Ponds Limestone, Upjier Silurian. The 

 limest(nie is the "coralline " or "fourth" limestone of Prof. 

 T. W. E. David's Yass section'^ ov immediately below the 

 Hatton Corner (? Humewood) Limestone-^, the uppermost 

 limestone bed of the Yass River series. 



- Schluter— Verhandl. Nat.-Vereines Preuss. Rheinl. Wcstf., 

 xxxvii., 18S1, pi. viii., tigs. 1 and 2. 



:: David— Ann. Rcpt. Dcpt, .Mines N. S. Wales, 1881 (1882), p. !48, 

 map and sections. 



■* The " Coral-reef " of .Icnluns — Proc. Lmn. Soc. N. S. Wales, 

 iii., 188, p. 26. 



