i&O RECORDS OF THE AUSTRALIAN MUSEUM. 



On the occurrence of the GENUS COLUMNARIA in the 

 UPPER SILURIAN ROCKS of NEW SOUTH WALES. 



By R. Etheridge, Junr., Curator. 

 (Plate viii.) 



I BELIEVE I am correct in stating that Columnaria has not so far 

 been recognised as an Australian genus of Palfeozoic Corals. When 

 1 had the pleasure of examining the Museum at St. Stanislaus 

 College, Bathurst, a few months ago, under the guidance of the 

 Rev. Father Dowling, I observed a coral from Molong, that I 

 took to be Columnaria from macroscopic characters only, sub- 

 sequently confirmed, however, by microscopic. At any rate if 

 the coral in question be not a species of this remarkable genus, 

 then the candid confession of my ignorance as to its systematic 

 position must be made. Father Dowling courteously allowed me 

 to divide the specimen, a portion of which is now in the Australian 

 Museum. 



The composite corallum (PI. viii., Fig. 1) is small, hemispherical, 

 but whether flat, rounded, or subpedunculate at the base, I am 

 unable to say. The colony only measures about two inches square, 

 ar4 is thus even less than in C. calicina, Nich. The surface is 

 covered with shallow polygonal calices that are circumscribed by 

 prominent margins, crenulated by the strongly marked septa very 

 distinctly visible in a weathered specimen. The eorallites are 

 closely compacted, contiguous, and completely united by their walls. 

 Tetragonal, quadrangular, pentagonal, hexagonal, or even irregular 

 eorallites were observed, in contact throughout their entire course, 

 without any partial separation, even near the mouths as in C. 

 calicina, Nich., or some conditions of C. alveolata, Goldf. In 

 thin sections prepared for the microscope, the walls are found to 

 be composed of uniform grey sclerenchyma (stereoplasma), with 

 only here and there any trace of a primordial wall separating 

 them as a thin brown line ; the amalgamation is therefore so per- 

 fect that nearly all trace of primordial demarcation is practically 

 lost. Thus, in one instance, there is to be noted a decided depar- 

 ture from the microscopic structure of Columnaria described by 

 Nicholson.* The eorallites have a very constant diameter of one 

 millimetre. In longitudinal sections (PI. viii.. Fig. 7 ) the sameappear- 

 ances are visible, the eorallites also presenting the narrow tube-like 

 structure of the Favositida3, but without the mural pores of the 

 latter. There are only sixteen septa, equally divided into primary 

 and secondary, the former extending across the visceral chambers 



* Tabulate Corals Pal. Period, 1879, p. 192. 



