303 THE OCCURRENCE OF GRAPTOLITES NEAR YASS, NEW SOUTH WALES. By Kathleen Shekrakd, M.Sc, and R. A. Keble, F.G.S., Palaeontologist to the National Museum, Melbourne. (Plate XV ; twenty-five Text-figures.) [Read 27th October, 1937.] Graptolites of both Upper Ordovician and Silurian age have been found near Yass. Upper Ordovician assemblages were discovered in slates at several localities in the Parishes of Morumbateman, Mundoonen and Manton in the Yass River District, all situated between 12 and 15 miles east of Yass and near the Yass-Gundaroo road (Sherrard, 1936&). These graptolites of Upper Ordovician age were found in rocks hitherto mapped as Silurian, which age was probably assigned to them on account of their comparative proximity to beds carrying Silurian fossils near Yass. No other fossils were found with the graptolites. Silurian graptolites occur at a locality known as Silverdale, seven miles to the north-west of Yass (see Text-fig. A), where several species of Monograptus have been obtained (Sherrard, 1934, 1936a). All were found in one small outcrop, which also yielded brachiopods, crinoid stems and traces of trilobites. Upper Ordovician Beds. These beds are blue and grey shaly slates, all dipping at high angles, 50 degrees and more, and striking between north-west and west-south-west. The slates cleave easily, but have not the fissile cleavage of roofing slates. In some cases they are puckered and contorted, while in others mineral solutions have penetrated freely along the bedding planes, probably often obscuring graptolites. In some specimens the material of which the graptolite impressions consists has been dissolved away, leaving merely an unidentifiable negative impression, surrounded by a white film. The graptolites found at the various localities are: Loc. 1. — Portion 24, Parish of Morumbateman, on Yass-Gundaroo road, 100 yards west of 12th mile-post: Climacograptus Mcornis Hall, C. missilis Keble and Harris, Diplograptus (Orthograptus) calcaratus Lapworth. Loc. 2. — Portion 1, Parish of Mundoonen, 200 yards north of Morumbateman road junction: Diplograptus {Orthograptus) calcaratus Lapw. var. feasiZicws Lapw., D. cf. truncatus Lapworth, D. sp. indet., Climacograptus missilis Keble and Harris, C. sp. indet., Cryptograptus tricornis Carruthers, Retiograptus yassensis, n. sp., Dicellograptus cf. complanatus Lapworth, D. cf. sextans Hall, D. sp. indet. Loc. 3. — Portion 152, Parish of Manton; about centre of Portion, 50 yards north of Yass River: Dicellograptus elegans Carruthers, D. cf. complanatus Lapworth, D. cf. moffatensis Carruthers, D. cf. pumilus Lapworth, D. cf. sextans Hall, D. cf. smitlii Ruedemann, D. sp. indet. Loc. 4. — Portion 61, Parish of Manton, eastern half: Dicellograptus divaricatus Hall var. rigidus Lapworth, D. cf. complanatus Lapworth, D. elegans Carruthers, D. sp. indet., Diplograptus (Orthograptus) calcaratus Lapworth var. basilicus
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