112 PROCEEDINGS OF SECTION C. 



and below. It also makes a very good dividing line between the 

 upper and the lower series of the Yass Beds. The former being 

 highly fossiliferous, whilst the latter are for the most part barren. 



Immediately above the Leper ditia zone is about ten feet of 

 barren calcareous sandstone. This is followed by about three feet 

 of compact fossiliferous limestone, containing, amongst others : 

 Heliolites and Spirifera plicatella. Succeeding this is a thin layer 

 of micaceous sandstone, followed by about three feet of highly 

 fossiUferous calcareous mudstone, which exhibits on the weathered 

 surface Heliolites interstincta, Favosites, Cystiphyllum, Rhizo- 

 phyllmn inter pundatum, deKon.,i?. robustum, Shearsby, Tryplasma, 

 Spirifer plicatellus, Orthothetes shearsbii, Dun, Camarotoechia, 

 Murchisonia, and Encrinurns punctatus, Brunn. This is succeeded 

 by about 150 feet of shales and mudstones, from which I have not 

 yet obtained any fossils ; but the next bed of limestone, only a few 

 feet thick, contains a large number of fossils : — 



Carpospongia, Heliolites interstincta, Heliolites, Favosites, Chce- 

 tetes, Cyathophylliim (a smaU species remarkable for its beautiful 

 calicular budding and rootlets), Zaphrentis, Pachypora, Rhizophyllum 

 inter punctatum, Crinoid remains, Lingida cff. lewisii, Sow ; Orthothetes 

 shearsbii, Dun ; Meristina australis{?). Dun; Atrypa reticularis [L.], 

 Orthis {Dalmanella) elegantida{?) ,Da}m. ; Spirifera fimbriata {?),ton- 

 ra.d; Limo pier i a {?), Megambonia, Grammysia, Loxonema, Cyclonema, 

 Paracyclas, Chonetes, Rhynchonella, Bellerophon, Orthoceras, Endo- 

 ceras, Montieiilipora, Encriniirus punctatus, Brunn. ; also Girvanella 

 (?)pisolitica, Wethered(.?), on a Limopteria shell. 



This limestone is succeeded by about 150 feet of sandstones 

 and calcareous shales, with a few undeterminable fossils. These 

 beds dip to the S.W. and disappear under No. 3 bed of porphyry. 

 To the south, at the Rifle Range, the Yass Beds are very much 

 faulted and folded. In the target pits are to be found Leperditia 

 shearsbii. Chapman, and Lingula. On the Flagstaff Hill is an out- 

 crop of quartzite, with numerous annelid burrows referable to 

 Arenicolites ; while the limestone on the eastern boundary of the 

 paddock contains the same fossils as mentioned in the other lime- 

 stone beds. 



As previously mentioned, the Yass Beds cross the railway hue 

 near Yass Junction, and continue on from there about 20° W. of N., 

 where, in the DerrenguUen Creek at Wargeila, a good outcrop is 

 found. They are best studied in portions 75, 76, 63, 70a, 62 and 

 53 of the parish of DerrenguUen. At this locality the creek has 

 exposed a series of false-bedded sandstones, grits, shales and lime- 

 stones as at Yass. The fossils are beautifully preserved in the hme 

 stones, and being in many instances silicified weather out perfectly 

 from the limestone matrix. Corals such as Rhizophyllum a.nd a 

 very small Cyathophyllum are preserved in silica to the minutest 

 detail, the rootlets of both, although very delicate and long, being 

 preserved in a most wonderful manner.^ The brachiopods are also 

 well preserved ; in fact the beds here do not bear any evidence of 



1 Shearsby, A. J. : " Operculate Corals from N.S.W.," Geol. Mag., Vol. III., 1906, p. 551. 



