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Vee, an : * vgs “. . os ele} ie PH iat hi Aare tae Peer aa as eet HEN Sal ' : ates a Pak titre v4 2 : ae ra Sra a an ; Beare Sra a a ae ae ro £44,084, otha pate y os an) ore raw. ae ote Bats : i ee FOL Gg Foe . 4 ak ee at > hes : ie 4s Deere at ria Po tfaea eS ee rie, . on :: 4 arpgeg hy PL atys bo Oleg Fae X i $3 ap Poors bese Mem e izipew pence ; . an adhe mires tee Ee ae ’ ak Pare Pun PPS Oe poh gengs ORD meee geeieag a ee ' ‘ ' Hobie LAPhY yo amie do pi regraky 7 i Fi oily aes ; Son a SL Coates Ene Wis ety & Bry. cate Bh Gl, ‘ £Fe a> bere F oy, aa ed, Fae ws twine 7 : < i Pas ar ee wah F Pe ctl) MV Ge Ed eek | ig 8 : m6 i ane dig hte CPE PY se th tey'g ene vedere Boe Das ge 1 ede nes Beco ie wee ee ra + Serr ate Mes DA hs Des ae em ttl tase oe It a ed ‘ ’ Few et dre yO phn F ; PP Ober etn SGT auyty # bes weber od ite wie ory, : rae Tina 551989: bb eed be ‘ Paes Ute wet pare : . ide 3 ‘ ete Sie F : i sleet . ” en yee iy “9 Pee Pate Divine Ee Panny gm ' Va sera ste i vas , Paes fj 5 Te : ang i 4 fe J f - ory oe ; i Dv Sethe ey : Va ey ’ ee) / Bb Aira * urasys 5 ? aay ‘ : “4 ed z ’ xy % A S-Au-S[ychey) — HARVARD UNIVERSITY e Library of the Museum of Comparative Zoology —" ‘ rhe ue , c ae re F j cn aoe ‘ 7 pay Le ae eq) ae - ~ ~) —— JOURNAL AND PROCEEDINGS OF THE ROYAL SOCIETY OF NEW SOUTH WALES PARTS 1-4 VOLUME 108 1975 PUBLISHED BY THE SOCIETY, SCIENCE HOUSE, GLOUCESTER AND ESSEX STREETS, SYDNEY Royal Society of New South Wales OFFICERS FOR 1975-1976 Patrons His EXcELLENCY THE GOVERNOR-GENERAL OF AUSTRALIA THE HONOURABLE SIR JOHN KERR, K.C.M.G., K.St.J., Q.C. His EXCELLENCY THE GOVERNOR OF NEW SOUTH WALES Sir RODEN CUTLER, V.C., K.C.M.G., K.C.V.O., C.B.E. President E. K. CHAFFER Vice-Presidents J. W. PICKETT, M-sSc., Dr.phil.nat. D. J. SWAINE, B.Sc., Ph.D., F.R.A.C.1. M. J. PUTTOCK, B.Sc. (Eng.), M.Inst.P. PSD) ae, BIA. PhD: W. E. SMITH, M-Sc., Ph.D., M.Inst.P. Honorary Secretaries J. W. HUMPHRIES, B.Sc., M.Inst.P. M. KRYSKO v. TRYST ((Mrs:), Bise; Grad.Dip., A.M. Aust.I.M.M. Honorary Treasurer A. A. DAY, Ph.D., F.R.A.S. Honorary Librarian W. H. G. POGGENDORFF, B.Sc. (Agr.) Members of Council F. C. BEAVIS, B.Sc., Ph.D., F.G.S. D. H. NAPPER, M:\Se. (Syd.), Ph.D. (Cantab.) G. S. GIBBONS, Msc. Ph.D. J. L. GRIFFITHS, M.A, Msc. Be ee Be 3 BAS Casey D. K. HUGHES, Bsc., Dip.Ed. fa nse GC; LOWENTHAL, B.A., M.Sc., Ph.D., F.A. Inst. P. W. B. SMITH-WHITE, M.a. New England Representative: N.T.M. YEATES, D.Sc. (Agr.), Ph.D. (Cantab.) South Coast Representative: G. DOHERTY, B.Sc., Ph.D. Executive Secretary: VALDA LYLE (Mrs.), A.LP.S.A. 3 ; CONTENTS Parts 1-2 Astronomy : Occultations Observed at Sydney Observatory 1973. K. P. Sims Earth Rotation Related to Net Electric Charge—Communication to Editor— J. Michelson Biochemistry : Potential Antitumour Activity of Some Amino Acid Metal Bs Sa A. J. Charlson, Kevin E. Trainor and Edward C. Watton ‘ : ue sh me Geology : Bedrock Topography in Northern Jervis Bay. B.D. Johnson and A. D. Albani Structure and Jointing in Permian Rocks Near Ravensworth, New South Wales, Northern Sydney Basin. D. R. Gray The Geology of the Windellama Area, N.S.W. Ruth Mawson The Merrimbula Group of the Eden-Merrimbula Area, N.S.W. J. Steiner Mathematics : Local Compactness and Free Products of Topological Groups. S.A. Morris Palaeontology : Lower Silurian Rugose Corals from Central New South Wales. R.A. McLean Note on Fossil Megafloras of the Nymboida and Redcliff Measures, Southern Clarence Morton Basin, N.S.W. J. E. Flint and R. E. Gould fi) as a Ae Upper Ordovician Coral Faunas from North-Eastern New South Wales. R. L. Hail Parts 3-4 Chemistry : Wool Research in the Division of Protein pe oogth C.S.1.R.O. W. G. Crewther and W. G. Lennox Geology : The Garra Formation (Early Devonian) at Wellington, N.S.W. Brian D. Johnson Hydrothermal Ca-Al Silicates in ic eat, Rocks near Coolac, N.S.W. dH. G. ve and A. S. Ray : : : : Petrology and Se caged of rengoee Rocks in the sansa Area of New South Wales. Judith M. Bean , : pie a iii 52 54 70 75 96 111 119 131 iv CONTENTS Contents—Continued Palaeontology : Continental Reconstructions and the Distribution of Coral Faunas during the Silurian. Presidential Address, 2nd April, 1975. John Pickett Some Early Cretaceous Organic-Walled Microplankton from the Great Australian Basin, Australia. Roger Morgan The Functional Anatomy of Phacopid Trilobites : Musculature and Eyes. Clarke Memorial Lecture, 1975—delivered 10th July, 1975. K.S.W.Campbell .. Plant Physiology : Bud Failure of Stone Fruits—Some Changes in Development and Chemical Composition of the Flower Buds of Peach (Prunus persica L. Batch). AH. D. R. Malcolm Report of Council, 31st March, 1975 Balance Sheet Index to Volume 108 List of Office-Bearers, 1975-1976 147 157 168 189 203 205 209 ii “™\] CJ\ J t ‘\ ' ' / | i i \ { =, 7 i : \ i = ~*~ VOLUMI - ‘ ( ~~ ‘ \] ; f i i ( iA" 4 A _ . 4 y20spag~si-—— Ava JYVH SUOIJOIS alijopoayL VF AVE -“SIAMAL BEDROCK TOPOGRAPHY IN NORTHERN JERVIS BAY imiod 038 B. D. JOHNSON anv A. D. AEBANI 14 ee Ee SE aT sc — . a an ‘A-X 9SIOACIZ Buole uoyeze1d103ur s}t pue afyord ssHIedsS—'Z aunoIy "re r FED 73 RMT NN gt BITS 8 %, 3°. r BYE MOL a Sasa tryed pA ey nyion sss a te Gt DAN DAN Can AA ‘ thsi a, Wage ee BP nn hades, CMAP TE ana Poor RAS wo : A ta AL ERE is ‘ : fe ial a Poe nt natone) A A wh * Wee f ie er ; : P i WY. get buarrs a te v3 rine ; af ” . * ait, Ned A _ ahs Be hs Aa ts Ben ‘y Rare h wires ¥ i ea! : ies ¥ Kua Mnuaten A on ° ha h pales X0UC36 f . a ei “AE War is Wy 2 MR ae 3 - “ ¢ ui ‘ é ~ gat » Sats ¥. oo ae ag juaWwIpes y TRAIN, D2}2P!]0SUOD » ' Aye ised . Pee te a Me Nw nig Ol pra A ~— Big se ‘ ( = == heen > a oe nw ee ~~ oe 2 == acca ioe RRND SINR REIN eNO ak it HOO 1S 3S (pum MaNetnse 3WIL AVM 3NO SGNODSSINNIA QUOTAS at LAV AAREICVES op UN Aue xt ua LON aah RAN KARI wht yi , wee af NV ug avy hehe We vale Va ial nadia PONY yn wha? “a > gl a i - mi KA We 5 Ne Pret tiks . " nay a FY mn <4: Why 4 ar Say ef -% wan " ), WAN 23 BEDROCK TOPOGRAPHY IN NORTHERN JERVIS BAY ges 5) Conclusion A sparker survey of the northern part of Jervis Bay has confirmed the northern extent of the dendritic drainage pattern, previously described, and of a minor drainage system which, in the northeastern part of the bay, is separated by a buried bedrock ridge. This latter system has its exit to the sea across the tombolo which presently joins the Beecroft Penninsula, of which Green Point forms the northwesterly projection, to the mainland. It may be reason- ably predicted that a steep sided bedrock canyon will be found underlying the tombolo and achieving depths well in excess of 100 metres below present sea level. The presence of the bedrock channel system confirmed by this survey and the previous work may be interpreted in terms of a drainage pattern cut during the Pleistocene and subsequently filled by sediment after the sea level rise at the end of the Ice Ages (11,000 years ago). It is interesting to note that our studies have shown B. D. Johnson, School of Earth Sciences, Macquarie University, North Ryde, N.S.W., 2113. A. D. Albani, School of Applied Geology, University of New South Wales, Kensington, N.S.W., 2033. similar results for both Broken Bay and Jervis Bay. Departures from the above pattern will probably require an interpretation in terms of local movements. Acknowledgements The authors are grateful for the assistance of J. Bishop, P. G. Towson and the R.A.N. Training College at Jervis Bay. References Avpanl, A. D., 1973. The Sedimentary Environment and the Distribution of Recent Foraminiferida in Broken Bay, N.S.W. Ph.D. Thesis, University of New South Wales. ABaNI, A. D., CARTER, A. N., and JouHNson, B.D., 1973. The Bedrock Topography and Origin of Jervis Bay, N.S.W. Oceanography of the South Pacific 1972, comp. R. Fraser, N.Z. Nat. Comm. UNESCO, Wellington. AvsBani, A. D., and Jounson, B. D., 1974. The Evolution of Broken Bay, N.S.W. Jour. Geol. Soc. of Australia, 21 (2), 209. (Received 30.4.74) Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 16-28, 1975 Structure and Jointing in Permian Rocks Near Ravensworth, N.S.W. — Northern Sydney Basin | Davip R. GRAY AssTRACT—Permian rocks near Ravensworth, New South Wales are part of the northern margin of the Permo-Triassic Sydney Basin. northwest trending non-cylindrical folds. Major structures in the area are open, sub-horizontal, The Bayswater and Glennies Creek Synclines and the Camberwell Anticline are the largest of these structures. The folds are second phase en echelon “pod ”’ folds developed on the eastern flank of the Muswellbrook Anticline. The main faults near Ravensworth are the Hunter Thrust and the Hebden Fault. The Hunter Thrust is a major border thrust along the northern margin of the Basin which separates Permian and Carboniferous strata. The Hebden Fault is a high angle reverse fault which closes against the Hunter Thrust forming a fault wedge of folded Permian strata. Four major systematic joint sets (north-northeast, north-west, north-south and east-west) occur in the rocks and appear to have developed independent of folding and faulting. Modification of joints in strata adjacent the Hunter Thrust has taken place because of movements along the Thrust after joint formation. The deformational history of Permian rocks along the northern margin of the Sydney Basin involves two periods of folding, a protracted period of thrusting and a phase of jointing. Introduction This paper describes the structure and jointing in the Ravensworth area, New South Wales and attempts to elucidate the deforma- tional history along the northern margin of the Sydney Basin. It is derived from work under- taken as part of a B.Sc. Hons. degree at the University of Newcastle in 1971. The Ravensworth area is situated between Singleton and Muswellbrook some 96 km northwest of Newcastle. It contains Late Permian strata in faulted contact with rocks of Carboniferous age (Figure 1). The oldest Permian rocks, the Maitland Group, crop out in a fault wedge between the Hunter Thrust and the Hebden Fault. These consist of fine, medium and coarse grained lithic arenites, pebbly arenites, cobble conglomerates with minor pebble phases (Branxton Formation) and a massive siltstone with minor arenaceous phases (Mulbring Siltstone). The Maitland Group is conformably overlain by the Singleton Coal Measures which are equivalent in age to both the Tomago and Newcastle Coal Measures. The Singleton Coal Measures consist of three formations, the Saltwater Creek Formation, the Vane Formation and the Goorangoola Formation (Robinson, 1969). The Coal Measure rocks include sand- stones, shales, mudstones and coal seams which pass upward into sandstones and conglomerates. The stratigraphic nomenclature used is dependent on persistent coal seams as formation boundaries. Mapping the outcrop of these coal seams is very difficult because of poor exposure. A stratigraphic and a structural interpretation of the area is also difficult due to the poor outcrop, the poor lateral continuity of the strata and the lack of any distinct marker horizons. All grid references cited refer Camberwell 1 : 63,360 military sheet. to the Structure The Ravensworth area, part of the Dome Belt (Voisey, 1958), is situated in the mildly deformed zone between the Lochinvar and Muswellbrook Anticlines, the two major structural elements in the northern section of the Sydney Basin. Folding The area mapped contains a series of folds which are essentially minor warps on the eastern flank of the Muswellbrook Anticline (Figure 2). This structure has an easterly dipping, north-south trending axial plane and plunges at 4:5 degrees to the south (Veevers, 1960). First phase folds, such as the Muswellbrook and Lochinvar Anticlines are large regional structures with north-south axial plane traces. They have similar trends to fold and fault trends BR Me swelivrook ék- 1 > —— LEGEND 17 STRUCTURE AND JOINTING IN PERMIAN ROCKS Cl ; dq ~~ ———SS= ajlubsog g ie Wi ayldts di 3) | f ‘ wes Bae awiojouy Sb Wy “4D J8sDMy/DS y, Pajoljuauayjipun aN aullQuhs —e | (uM) 31V9S eine ves ; AMVILYAL — wag je0g sang “SHOUSINOSUYD aujouuy — | S ayiyong WO8S |[aPpiq |And s $a104 mete FAN a tats Moca Bl [i] \W4 voixuDig Famed ino} isnau) =o YONDWIOJ BUDA [+ = asiacas aj6un ybiy = wniantiy [0] ‘ws Jajomshog ging [F SUOISHIS sLinv4 bulqinn bo Pasaju; —g— ———— W4 djooBuDJ009 Pe 4 ke AUWNYaLVNO S@INSDAW [009 uojaiBuIS dnojg pudj}!0W bi be ane = Oh Wea _"NVINU3d “NVIWU3d av3931 21901039 = “= BE BERCRE 2 et? i N: — Poe oe A VOUDIS JOMOd 7 Ws HepPr) uoNoIS B14 jnd-uedo Asa i[10D aBDIIIA SKOM|IDY Syd0d, eee= == = sppoy ‘MSN SS NOIO3Y HLYOMSNAAVY — K : aus 40 ABoj0a9 =e ON3931 P EF : : =) All formation boundaries in the ap of the Ravensworth area, New South Wales. ingleton Coal Measures are projected seam outcrops from Booker (1953). iS} FicurE 1.—Geological m DAVID R. GRAY 18 yPD11 / poy UDIWJ3q4 snoJaj1uog405, ayluyS pud dig auljauy w auljauAS > QNn39371 Structure Map of the Ravensworth area. 2. FIGURE STRUCTURE AND JOINTING IN PERMIAN ROCKS 19 in the lower and middle Palaeozoic basement rocks underlying the Sydney Basin. This may suggest that the first deformation affecting the Basin was largely manifested by the propagation SCALE HORIZONTAL VERTICAL AIS 1 CAMBERWELL ANTICLINE 1 BAYSWATER Al6 SYNCLINE’ j of basement structure into the overlying sedimentary pile, probably by differential move- movement along existing basement structural anisotropies. Blayden (1971) and Stuntz (1972) consider that the folding of the Lochinvar Anticline was influenced by underlying basement faults. Blayden (oP. cit.) considers that differen- tial block movement along basement faults has B. Section line X-Y, Figure 1. T5900 Sane ae es oe 1 1 r | i | 1 ' x) a 2 ~ o>) ° Zeteb 1 HEBDEN FAULT on. XC Soolo5o SYNCLINE LP o'o5°a ol > ° GLENNIES CREEK 200 A. Section line S-T, Figure 1. O1 CAMBERWELL ANTICLINE aAEHNORT Dee FiGuRE 3.—Geologic Cross Sections. BAYSWATER SYNCLINE 32,8 6|0%° ° oo? Ou oo been responsible for many of the structures in the Sydney Basin. The open, subhorizontal to gently southeast plunging, north-west trending folds in the 20 DAVID R. GRAY 072940C D 063890C fern, Domain B 0588698C O75976C C : ee ) oY ver! 4S? s dippi ALT fo ) - ya, 7 f 7 , / i 7 / WA a / 9 face fern, Domain A pL EY EY yl y race Fy eae f minor join’ lated joint lated joint 060994 Cc y= tasy ‘6 Q ga Ficure 4—See next page for Legend. Ravensworth area, of which the Camberwell Anticline and the Bayswater and Glennies Creek Synclines are the largest, are non-cylindrical folds whose profiles change progressively from north to south (Figure 3). The folds have amplitudes of 0-2 km and wavelengths of 0-5 km in the north and amplitudes of 0-4 km and wavelengths of 2-5 km in the south. These local minor folds are probably en echelon “ pod ”’ folds which have formed during a second phase of west-northwest folding, associated with thrusting movements along the _ Hunter Thrust. This second deformation super- _ posed on the first generation folds was at 60° to the first folding compression direction. - Buckling experiments on intersecting fold _ patterns in putty (Gosh and Ramberg, 1966, - Plate IIIB, p. 101) show that such a superposed | deformation will produce arching of the first phase folds and the development of smaller en echelon “pod” folds on the limbs of these folds. The development of dome and basin | structures, such as the Belford and Loder Domes | along the northern margin of the Basin reflect the arching of the first generation structures, in this region. Mapping has shown that the Rixs Creek _ Syncline (Booker, 1953) is a continuation of the | Glennies Creek Syncline. The name Glennies Creek Syncline has been retained for this ‘structure. The Bayswater Syncline plunges _ approximately at 7° to the south-southwest (154°), whereas the Camberwell Anticline and | Glennies Creek Syncline plunge locally to the _morthwest at 9° and 7° respectively. Sub- surface data (recorded in Gray, 1971) indicates a reversal in plunge for the Camberwell Anticline at 052942C ; the plunge changes to 9° to the _ south-southeast (143°). There is a general | tendency for the fold trends to swing from .|}| north-northwest to west-northwest northwards on the diagram. REC ROMO MOOD the overthrust block. STRUCTURE AND JOINTING IN PERMIAN ROCKS 21 through the area. Plunge reversals and curvi- linear axial plane traces are due either to differential shortening along the folds during their formation or subsequent modification by later thrusting movements along the Hunter Thrust. Faulting The main faults in the Ravensworth area are the Hunter Thrust and the Hebden Fault. The Hunter Thrust, a major border thrust along the northern margin of the Sydney Basin, consists of a series of dislocations separating Permian and Carboniferous rocks. It extends over 80 kms in a northeast direction, from north of Newcastle to Scone. The fault trace, generally covered by soil and alluvium is delineated by the marked physigraphic difference between the Permian and Carboniferous strata. The thrust plane is distinctly nonplanar in places (Osborne, 1929, and Raggatt, 1938) and in the mapped area appears conformable with folded Carboniferous strata in the overthrust block (Gray, 1971). Raggatt (op. cit.) considers it is convex to the southwest in section as well as in plan, with a dip varying between 15 and 30°. The Hebden Fault is a high angle reverse fault which closes against the Hunter Thrust near Falbrook to produce a fault wedge of folded strata. The fault plane strikes approx- imately northwest and has a calculated minimum dip of 77°. The throw at the northwest end of the fault must be in the order of 1,300 m, whereas drilling data indicate throws of 360 m and 240 m at 102938C and 129918C respectively. Drilling and outcrop data suggest considerable faulting in the southern portion of the fault wedge. Despite poor outcrop it appears likely that the Hebden Fault continues to the south to close against the Hunter Thrust in the vicinity of Falbrook. _ Ficure 4.—Interpreted systematic joint trace pattern in the Ravensworth area; contoured 7S diagrams (poles _ to joints) designated by upper case letters refer to stereograms designated by the corresponding lower case letter (Contours per 1% area.) . creekbed; 10%, 8%, 6%, 0% . creekbed; 16%, 14%, 12%, 6%, 0% creekbed ; 18%, 16%, 10%, 6%, 0% . Foybrook Open Cut; 20%, 16%, 10%, 8%, 6%, 5%, 0% . Liddell Colliery Portal; 13%, 11%, 8%, 6%, road cutting; 20%, 15%, 11%, 9%, 4%, 0% Pukes Gulley Open Cut; 26%, 22%, 16%, 8%, 0% Elemin Ravensworth Cut; 13%, 12%, 9%, 7%, 0% creekbed, Bowmans Creek bridge ; Hebden Open Cut; 30%, 22%, 12%, 7%, 0% . Tidge outcrop; 10%, 8%, 6%, 5%, 3%, 0% . creekbed; 15%, 10%, 7%, 6%, 3%, 0% . disused quarry; 8%, 7%, 5%, 3%, 0% , L, and M are joint measurements from Carboniferous ignimbrites in Yo 9% 13%, 12%, 9%, 6%, 2%, 0% 22 DAVID R. GRAY No evidence was found for the York’s Creek Fault (Raggatt, 1938, and Booker, 1953), as it is clear from outcrop that the Maitland Group strata terminate against the Hebden Fault. A north-northeast striking fault, however, occurs along the western boundary of the Ravensworth State Forest (110950C) and has an approximate throw of 120 m. Minor faults with throws less than 15 m are common in the Singleton Coal Measures. These cannot be detected on the surface and are usually exposed in colliery workings and open cut mines (Plate I). This faulting occurs along northeast-southwest (N20E to N40E) and north- south directions. The northeast trending faults are mainly normal faults, with dips ranging from 54 to 76° predominantly to the southeast, together with high angle reverse faults with dips from 82 to 88° to the northwest. The north-south striking faults, more common in the western portion of the area, are generally reverse faults with dips ranging from 30 to 62° to the west. These minor faults characteristically occur not as isolated faults but in zones, and appear to represent two different sets of faults. The north-south reverse faults are probably related to the compressive Muswellbrook Anticline Phase, whereas the northeast-southwest normal faults are possibly a relaxation phase after the second generation folding. During the Tertiary some of these faults, predominantly the north- northeast normal faults, were opened up by igneous dykes. Jointing Jointing is by far the most ubiquitous structure in this area. Two domains of jointing exist, each characterized by the spatial attitude of the joints within it (Figure 4). Domain A Domain A geologically corresponds to weakly deformed strata south of the Hunter Thrust. Four’ essentially vertical “systematic ”’ (Hodgson, 1961) joint sets are developed: (1) north-northeast (N20E to N35E) ; (2) northwest (N45W to N55W); (3) east-west; (4) north- south (Plate II). Minor variations in the spatial attitude of joints occur across the area and are most probably related to varying lithology and the presence of sedimentary structures. It is well known that fabric and structural anisotropies in a rock body cause re-orientation of stresses responsible for fracture initiation and thereby produce local variations in the attitude of the fractures. Hills (1966) considers that features such as cross-bedding, ripple marks, sole marks, flute casts, concretions, nodules and _ fossils serve as loci for stress concentration and thus initiate the microfractures which propagate to form joints. Sedimentary fabric must therefore influence the direction and rate of propagation of microfractures, and is predominantly respons- ible for the irregular and often curviplanar nature of some joint surfaces. Structures on the joint planes and features associated with joints provide information about the origin and the genetic history of the joints. These include structures such as plume hackle marks and rib markings and features such as displacement indicators (sheared pebbles and fossils) and mineral infilling (Table 1). Plume hackle marks or plumose patterns are essentially curved striations which fan out from a common origin. They have been found on fracture surfaces identified from other criteria as shear joints (Parker, 1942, and Price, 1966) and also as tension joints (Nadia, 1950 ; Muehl- berger, 1961, and Badgley, 1965). Roberts (1961) claimed that plumose patterns typify fractures produced by extremely rapid medium separation, whereas Syme Gash (1972) has shown that they are generally indicative of shear fractures. Bed _ thickness, grainsize, porosity and the presence of pre-existing structures determine whether they form on joint surfaces (Syme Gash, of. cit.). Rib marking or augen fracture is a series of approximately semi-circular or arcuate ridges along the joint plane. They result from running shear fractures with multiple or con- tinuous shock sources (Syme Gash, op. cit.). The presence of both rib and hackle structures on the north-northeast and northwest joints (Plate III), as well asa variation in dihedral angle between them suggests a shear origin. The dihedral angle between shear joints is a function of the angle of internal friction of the material and consequently varies for differing rock types. Modification of some of these joints has ] occurred. Mineral infilling and displacements along north-northeast and northwest joints (Table 1) indicate both tensional and “ shear ” movements along some joints after their formation. Joints may provide a cumulative record of late tectonic events and therefore ~ lateral displacement along a joint does not necessarily indicate a shear origin, only a phase of shear movement. Similarly, the presence of mineral infilling does not necessarily indicate a tensional origin, only a phase or component of 23 STRUCTURE AND JOINTING IN PERMIAN ROCKS OLO6SLL 0£66LS0 9266250 92¢6900 9992920 0464420 909622 026900 9226900 0L96960 9L96960 9196960 9296920 98E61L20 9496920 9126096 9126096 peqyeedg peqyeery peqyesrg kizene Teaeiry peqyesig peqyeeto Ppeqyeet) Lirenh Teaeiy AIIENY Teaesy yueqyeesg yueqyeedg yueqyeetg 9nD 2 °ON wWeysng qnyg uedg uspaqey 4NQ 2 °ON weysng 49D PTO AeTIND sexkg 41D PTO £eTIND soxkg NOTLVOOT MSSN HOON queuoduog TeOTz4en WhHeN (queuodwuog TeyuozT4toH) MSeN (qusuoduog Te4uozT4oH) FON (seysey uoTSUS,) FON MSEN HSSN MOeN MOeN MOeN aHOcN peaAresqo suoy peAresqo suoN MOeN peArTesqo suoy MOSN MOZN MO+N ASSEN AMIaLS LNIOL saovfang qurof Fuojp saanjonas T alavy ey quoweoeTdstgq SUTTITJUL Tereuty SOpTSUSsHoTTs SutyseW qty SyTeW eTYOeY ewunTg HaYNLVAd YO AANLONALS a ecoieeand =. tem ideal tent em Sa! a ay Seed t- OS 24 DAVID R. GRAY Ficure 5—See next page for Legend. STRUCTURE AND JOINTING IN PERMIAN ROCKS 25 tension at some stage in the development of the joint. However, these are probably older than joints without infilling. The infrequence of hackle and rib markings, and the more uniform orthogonality between the north-south and east-west joints suggests a tensional origin. Domain B Domain B corresponds to disturbed Permian strata adjacent the Hebden and Hunter Thrust Faults. Subsets of the four main systematic joints sets of Domain A are present, but are associated with subsidiary joints separated by small dihedral angles. Domain B joints, how- ever, have extremely variable dips and are generally not close to vertical. Modification of joint sets is marked in Domain B, where slickensides, sheared pebbles (Plate IV), mineral infilling and extremely close joint spacing (down to 1 cm) are more common (Table 1). The general lack of hackle marks, the presence of slickensides and sheared pebbles indicates that movement along joints has predominantly accompanied modification of Domain B joints. An incipent fracture pattern present in a rock mass is accentuated by all subsequent stress conditions (Spencer Jones, 1963). Existing cracks and flaws propagate further before point stress concentration enables new crack formation. This would generally decrease spacing between joints and therefore increase joint frequency. Some zones _par- ticularly favourable to stress concentration could develop extremely closely spaced jointing, characteristic of “shear zones ”’. Modification of jointing has been associated | with thrusting movements along the Hunter Thrust accompanied by subsidiary movements along the Hebden Fault. The complex faulting in the southern portion of this fault wedge reflects the deformational intensity of this zone. General Observations on Jointing (i) In both domains there is a definite lithologic control of jointing, since the orientation, planeness and spacing of the joints are dependent on lithology. It is clear that the joints are more closely spaced in shales and siltstones than in sandstones. Price (1959) suggests that joint spacing is related to the strain energy originally stored in the rock. Different rock materials under the same stress will have different strain energies, depending on the Poisson Ratio and Youngs Modulus of the material and therefore different joint spacing. It has also been theoretically shown that joint frequency is proportional to bed thickness and the inverse of the square root of the shear modulus of the neighbouring beds (Hobbs, 1967). (iu) The development of jointing appears sporadic as not all joint sets are present at some outcrops (Figure 4). Surface jointing may not necessarily be representative of the entire joint pattern originally developed in the rock (Chapman, 1958, and Secor, 1962). Incipient jointing in buried rocks undergoes surficial enhancement at the surface, where selective weathering processes and topographic relief may utilize and open up a few favourably oriented joint sets whilst others being unfavourably oriented remain closed. This may explain the absence of some joint sets at the various localities. (ui) There is an angular difference between the cleat in the coal and the jointing in strata, above and below the coal seams (Figure 5). FicurE 5.—S diagrams of cleat and joint measurements (all poles to joints and clear; contours per 1% area). 1. Elemin Ravensworth Cut: a. poles to cleat; 36%, 30%, 20%, 10%, 0% b. poles to joints ; 2. Newraven No. 2 Cut: Taoe 12%; 9%, T%y- 0% a. poles to clear; 22%, 20%, 15%, 10%, 5%, 0% b. poles to joints; 20%, 15%, 11%, 9%, 4%, 0% 3. Pykes Gulley Old Cut: a. poles to cleat; 34%, 32%, 22%, 10%, 0% b. poles to joints; 26%, 22%, 16%, 8%, 0% 4. Hebden Open Cut: a. poles to cleat ; b. poles to joints ; 5. Foybrook Open Cut: 15%, 10%, 0% 30%, 22%, 12%, 7%, 0% a. poles to cleat; 28%, 22%, 16%, 10%, 0% b. poles to joints ; 20%, 16%, 10%, 8%, 6%, 5%, 0% 2a values are dihedral angles for north-northeast and northwest cleat and joints. 26 DAVID R. GRAY Generally there are only two prominent cleat directions and these correspond to the north- northeast and northwest shear joints. The angular difference is probably related to the different dihedral angles (2« values, Figure 5) for the cleat and the corresponding joints ; the cleat dihedral angles are clearly larger than those for the joints. Also, Nickelsen and Hough (1967) consider that cleat in coal develops in response to stress differences too small to produce joints in sandstones and shales. Conse- quently, some of the angular variation could reflect slight changes in stress orientation between cleat and joint formation. Origin of the Jointing Joints which develop during the same tectonic cycle as folds and faults usually show well defined relationships to these structures (Nevin, 1949 ; Gilkey, 1953; Billings, 1954; de Sitter, 1956 and Goguel, 1962), whereas joints in areas where deformation has not been intense may show no definite relationships to the structures present (Parker, 1942 ; Harris, 1960 ; Hodgson, 1961 and Nickelsen and Hough, 1967). In the Ravensworth area joints show no clear relationships to the structures present. Jointing appears independent of folding as there are no apparent relationships between joint trends and axial plane traces of the folds. Also the joints are essentially vertical and do not remain perpendicular to bedding around the folds. Blayden (1971) in a study of the Macquarie Syncline, near Newcastle also found that jointing developed independent of folding. Jointing also appears genetically unrelated to faulting, although some modification of joints has occurred during subsequent faulting movements. In other areas where jointing is unrelated to tectonic structures (Parker, of. cit.; Hodgson, op. cit.), the joints are systematic over large areas and consistent through considerable vertical extent of rock. Jointing in the Sydney Basin is also systematic over large areas and is similar to the joint pattern in the Ravensworth region (Moelle, personal communication, 1971). Two theories have been put forward to explain the formation of such joints ; (i) Basement Propagation Theory (Kendall and Briggs, 1933 ; Blanchet, 1937, and Hodgson, op. cit.), where joints in areas were thick sedi- mentary piles overlie rigid basement blocks, are considered to propagate upwards due to alternat- ing torsional stresses resulting from gravitational earth tides. (u) Uplift-Expansion Theory (Price, 1959, and 1966), where joints result from residual principal stresses reoriented during uplift and unloading such that the mechanics of joint formation are a natural consequence of their physical properties and the sequence ot events to which the rocks | are subjected, namely burial, compression and subsequent uplift. The “ uplift-expansion ”’ theory is applicable for joint formation along the northern margin of the Sydney Basin since this region approx- imates the second model proposed by Price (1959, p. 160). Residual northeast compressive stresses probably existed in these rocks after the folding and thrusting movements. This model also satisfactorily explains the observed shear and tension joints in the Ravensworth area as discussed below. Since jointing appears independent of both folding and faulting in this area, joint development must have taken place | after folding and during the later stages of J thrusting. | The north-northeast and northwest shear joints would have formed first, at a point during uplift where gravitational loading became the intermediate principal stress. The north-south and east-west tension joints developed after further uplift, when the rocks passed into tension in the horizontal direction with gravitational loading the greatest principal stress. Subse- | quent thrusting movements have resulted in | modification of these joints, particularly in strata adjacent the Hunter Thrust. However, not all joints in the Sydney Basin are post-orogenic. Cook and Johnson (1970) present evidence from jointed “ironstone ”’ intraclasts that some joints in the Basin developed early in the history of the sediments (prior to contemporaneous erosion). These | joints would have been reactivated and modified ~ during subsequent folding and faulting episodes. | Another hypothesis put forward by Diessel ~ et al, (1967) assumes that distinct vectorial © sedimentary features determine the distribution ] and attitude of the joint pattern in the Sydney Basin. They found that the strike of the major — joint set coincided with the direction of deposi- tion. This coincidence in orientation may not necessarily indicate a regional dependence of jointing upon sedimentary anisotropies. It could infer a process-response relationship where the principal basement structural anisotropies control the shape and morphology of the sedimentary basin and thus the regional palaeo- current trends. Residual basement stresses, which are largely dependent on the basement morphology and the basement anisotropies, STRUCTURE AND JOINTING IN PERMIAN ROCKS 27 strongly influence the regional joint pattern. The jointing would therefore coincide with the regional palaeocurrent trends. The formation of joints in the Sydney Basin is probably extremely complex and therefore cannot be fully explained by one simple model, such as isostatic adjustment. This model, however, satisfactorily explains the development of joints along the northern margin of the Basin. Even so this does not necessarily preclude the presence of early formed joints (Cook and Johnson, 1970, and Moelle, 1972) and the super- imposed effects from upward propagation of basement anisotropies due to basinal subsidence (Blayden, 1971). Conclusion The structural history of Permian rocks along the northern margin of the Sydney Basin involves two phases of folding and a protracted period of thrusting. The first phase of folding is probably related to basement movements and a rejuvenation of basement structures in the overlying sediments. The second phase is related to northeast compression associated with thrusting movements along the Hunter Thrust. The first folding phase produced open, sub- horizontal, north-south trending cylindrical folds, characterized by the Lochinvar and Muswellbrook Anticlines. The second phase caused a broad arching of these structures about west-northwest and east-southeast axes produc- ing dome and basin structures, such as the Belford and Loder Domes, and en echelon “pod ”’ folds such as the Camberwell, Bayswater and Glennies Creek folds. Four systematic joint sets exist in the Permian rocks and appear to have developed independent of both folding and faulting. It is proposed that these are postorogenic joints formed due to lateral expansion associated with isostatic uplift. The following chronologic tectonic evolution jis envisaged for the structural development of ‘the northern margin of the Sydney Basin : (i) first folding phase producing open north- south cylindrical folds EARLY PERMIAN (i) development of the Hunter Thrust, associated with the second folding phase and the development of the Hebden Fault LATE PERMIAN (iii) regional uplift, and the formation of the north-northeast and northwest shear joints, followed by the north-south and east-west tension joints EARLY TERTIARY (iv) emplacement of igneous dykes, sills and plugs LATE TERTIARY It is possible that some folding accompanied Tertiary uplift, since Blayden (1971) considers that the Macquarie Syncline developed during the Cainozoic. He relates the geometry of the fold to basement faults and to the tilting of underlying basement blocks. The timing of the Hunter Thrust is uncertain. Since the Permian stratigraphy is different on either side of the Thrust, it must have existed as a major structural weakness in the basement rocks underlying the Sydney Basin before the Early Permian. However, significant move- ment did not take place along this structure till the Late Permian. Changes in palaeocurrent trends and the nature of sedimentation in the Newcastle Coal Measures (Branagan and Johnson, 1970) and the upper portion of the Singleton Coal Measures (Gray, 1974) reflect the initiation of structural movement associated with the Hunter Thrust. The main period of thrusting which affected the entire Ravensworth stratigraphy, probably followed not long after this initial or embryonic stage. Acknowledgements The author acknowledges use of facilities at the University of Newcastle and the assistance given by Dr. K. Moelle, Dr. R. Offler, and Messrs. B. Vitnell and D. Marchoni during the course of the work. Thanks are extended to Liddell Colliery, Hebden Mining Company, Foybrook Open Cut and Liddell State Mine managements for access onto their property. Finally, the author gratefully acknowledges the helpful discussion and comments by Dr. D. W. Durney in criticism of the various drafts of the paper. Technical assistance during preparation of the paper was provided by Macquarie University. References Banctey, P., 1965. Structural and Tectonic Principles. Harper, New York. Brrrines, M. P., 1954. Structural Geology. (Second Edition. Prentice-Hall Inc., Englewood Cliffs. BviancHet, P. H,, 1937. Development of Fracture Analysis as an Exploration Method. Am. Ass. Pet. Geol. Bull., 41, 1748. BLAYDEN, I. D., 1971. On the Structural Evolution of the Macquarie Syncline, New South Wales. Ph.D. thesis, University of Newcastle (unpublished). Booker, F, W., 1953. The Geology and Coal Resources of the Singleton-Muswellbrook Coalfield. Ph.D. thesis, University of Sydney (unpublished). BranaGan, D. F., and JoHnson, M. W., 1970. Permian Sedimentation in the Newcastle Coalfield, N.S.W. Proc. Australas. Inst. Min. Metail., 235, 1. 28 DAVID R. GRAY CHAPMAN, C. A., 1958. Control of Jointing by Topography. J. Geol., 66, 552. Cook, A. C., and Jounson, K. R., 1970. Early Joint Formation in Sediments. Geol. Mag., 107, 361. DiesseL, C. F. K., Driver, R. C., and Moe Le, K. H. R., 1967. Some Geological Investigations into a Fossil River System in the Roof Strata of the Bulli Seam, Southern Coalfield, N.S.W. Proc. Australas. Inst. Min. Metall., 221, 19. GiLkKEy, A. K., 1953. Fracture Pattern of the Zuni Uplift. Rep. Atom. En. Comm., R.M.E. 3050. GOGUEL, J., 1962. Tectonics. W.H. Freeman & Co., San Francisco. GosH, S. K., and RamsBerc, H., 1968. Buckling Experiments on Intersecting Fold Patterns. Tectonophysics, 5, 89. Gray, D. R., 1971. The Geology of the Hebden Region, N.S.W. B.Sc. Hons. thesis, University of Newcastle (unpublished). Gray, D. R., 1974. Sedimentology of Permian Rocks Near Ravensworth, N.S.W., Northern Sydney Basin. J. Roy. Soc. N.S.W., 107, 17. Harris, J. F., Taytor, G. L., and WatLpeEr, J. L., 1960. Relation of Deformed Fractures in Sedi- mentary Rocks to Regional and Local Structures. Am. Ass. Pet. Geol. Buil., 44, 1853. Hitt, P. H., 1966. Joints: Their Initiation and Propagation with Respect to Bedding. Geol. Mag., 103, 276. Hosss, D. W., 1967. The Formation of Tension Joints in Sedimentary Rocks: An Explanation. Geol. Mag., 104, 550. Hopecson, R. A., 1961. Classification of Structures on Joint Surfaces. Am. J. Sci., 259, 493. KENDALL, P. F., and Briacs, H., 1933. The formation of Joints and the Cleat in Coal. Pyoc. Roy. Soc. Edin., 53, 164. MoELLE, K. H. R., 1972. On Structural Analyses of Oriented Bore Cores from West Wallsend No. 2 Colliery Holding. Proc. Aus. I.M.M. Conference, 43. MUEHLBERGER, W. R., 1961. Small Dihedral Angle. J. Geol., 69, 211. Naval, A., 1950. Theory of Flow and Fracture of Solids. McGraw-Hill, New York. Conjugate Joint Sets of School of Earth Sciences, Macquarie University, North Ryde, N.S.W., 2118. Nevin, C. M., 1949. Principles of Structural Geology John Wiley & Sons, New York. NICKELSEN, R. P., and Houeu, V. N. D., 1967. Joint- ing in the Appalachian Plateau of Pennsylvania. Geol. Soc. Am. Bull., 78, 609. OsBorNE, G. D., 1929. Some Aspects of the Structural Geology of the Carboniferous Rocks of the Hunter River District between Raymond Terrace and Scone. Proc. Linn. Soc., 54, 436. ParKER, J. M., 1942. Regional Systematic Jointing in Slightly Deformed Sedimentary Rocks. Geol. Soc. Am. Bull., 53, 381. Price, N. J., 1959. Mechanics of Jointing in Rocks. Geol. Mag., 96, 147. Price, N. J.. 1966. Fault and Joint Development in Bnittle and Semi-Brittle Rock. Pergamon, Oxford. Racecatt, H. G., 1938. Evolution of the Permo- Triassic Basin of East Central N.S.W. D.Sc. thesis, University of Sydney (unpublished). Roserts, J. C., 1961. Feather Fracture and the Mechanics of Rock Jointing. Am. J. Sci., 259, 481. Rosinson, J. B., 1969. The Singleton Coal Measures. In Packham, G. H. (Ed.), The Geology of New South Wales. J. Geol. Soc. Aust., 16 (1), 350. Secor, D. J., 1965. Role of Fluid Pressure in Jointing. Am. J. Sci., 263, 633. Srrter, L. U. DE, 1956. Structural Geology. McGraw- Hill, New York. SPENCER-JONES, D., 1963. Joint Patterns and their Relationship to Regional Trends. Geol. Soc Aust., 10, 279. Stuntz, J., 1972. The Subsurface Distribution of the “Upper Coal Measures’’, Sydney Basin, New South Wales. Proc. Aus. I.M.M. Conference, 1. SyME Gasu, P. J., 1972. A Study of Surface Features Relating to Brittle and Semi-Brittle Fracture. Tectonophysics, 12, 349. VEEVERS, J. J., 1960. Geology of the Howick Area, Singleton Muswellbrook District, N.S.W. B.M.R. Report No. 53. VolsEy, A. H., 1958. Eastern New South Wales, Australia. Roy. Soc. N.S.W., 92, 191. Tectonic Evolution of North J. Proc. (Received 21.12.1973) EXPLANATION OF PLATES Plate 1.—Fault graben in Hebden Open Cut Mine (072940C) ; north-northeast trending normal faults | typical of the minor faulting in the Singleton Coal Measures. 4 Plate 2.—Joint trace pattern on bedding plane in creek bed near Bowmans Creek Bridge (063890C) ; north- northeast and northwest joint sets, with some north-south joints developed near hammer. approximately north-south. Hammer oriented Plate 3.—Plume hackle marks or plumose pattern, and rib or augen structure along northwest joints, Durham No. 2 Open Cut Mine (026967C). Plate 4.—Fractured pebble in pebbly arenite, creekbed (051993C) ; reflects a component of horizontal — displacement along a N60E joint. GRAY PLATES I—IV N.S.W JOURNAL ROYAL SOCIETY Introduction Windellama is located cn the southern table- | lands of New South Wales, 40 km S.E. of Goulburn and 224 km S.W. of Svdney. It is | an area of primarily rolling terrain, the land- | forms to the east becoming more rugged where | the underlying sediments have proved more resistant to weathering and erosion. The land- form pattern tends to be meridional, reflecting regional strike of the rocks. Previous Investigations The earliest comment on the geology of the Windellama area appeared in 1834 on the original survey plan drawn up by Robert Hoddle ; limestone hills were marked and the occurrence of “fine black marble” noted. Rev. W. B. Clarke (1860), in reporting on the limestone outcrops between Jacqua and Windellama, assumed a relationship between these and the Bungonia limestone. The commercial potential of the limestone was realized as early as 1874 when John Young opened a small marble quarry on Limestone ‘Creek, Windellama, to provide material for tiling the Great Hall at Sydney University. The curator of the New South Wales Techno- logical Museum, R. T. Baker (1909), regarded the “marble” from Windellama as “ the best black marble yet found in New South Wales ”’. W. G. Woolnough (1909) was the first to refer _ to the fossiliferous limestones at Windellama as being Devonian in age and to note the lithologic contrast with Silurian limestones of the Bungonia district. In a detailed study of the limestone, J. E. Carne and L. J. Jones (1919) recognized two belts corresponding to those shown in Figures 3 and 4 of this paper. They considered the limestone to be of Silurian age. M. D. be. Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 29-36, 1975 The Geology of the Windellama Area, New South Wales RutTH MAwson ABsTRACT—Mapping of some 50 km? in the Windellama area has revealed a sequence of 1,700 m or more of Early Devonian carbonate and terrigenous sediments downfaulted into rocks at least in part of Late Silurian age. The Devonian succession consists of approximately 200 m of terrigenous sediments overlain by about 283 m of carbonates, the Windellama Limestone, overlain in turn by a further 1,200 m or more of sandstones and siltstones. The Windellama Limestone yielded rich macro and micro-faunas of Early Devonian (Lochkovian) age. The overlying terrigenous sediments have yielded a coral-trilobite-brachiopod fauna of Early Devonian (Praguian) age. Garretty (1937) accepted this age assignment refining it to Late Silurian on the basis of fossils identified by W. S. Dun ; no identifications were listed. He noted that between Bungonia and Windellama the sediments differed considerably from the surrounding Ordovician and Silurian sequences and, on the basis of further fossil identifications by W. S. Dun, dated these as Late Devonian. G. F. K. Naylor (1949), in summarizing his previous work in the Goulburn district (1935a, 19356, 1937, 1939), assigned all the limestone of the area a Silurian age and identified the terrigenous sediments as belonging to either Ordovician or Silurian belts. It was not until 1970 that J. W. Pickett, in an unpublished report (1970), dated the Windellama limestone as Early Devonian (Siegenian-Emsian) age on the basis of : Heliolites daintreet Nicholson and Etheridge, Favosites cf. ovatiporus Hill and Jones, Aulopora sp., Tryplasma sp., Microplasma sp., and Tvupetostroma sp. Pickett and M. B. Huleatt (1971) refined the date to late Siegenian, based on a more complete faunal list. Pickett identified, iter alia, Favosites cf. ovatiporus Hill and Jones, Heliolites daintreet Nicholson and Etheridge, Pseudamplexus princeps (Etheridge), Tvyplasma cf. columnare Etheridge, Spathognathodus __ steinhornensts buchanensis Philip, S. inclinatus (Rhodes), Hindeodella priscilla Stauffer, Ozarkodina denckmannt Ziegler, Tvrichonodella wnconstans Walliser, TJ. symmetrica pinnula Philip, Plectospathodus alternatus Walliser. In a report for the mining exploration firm of Asarco (Australia) Pty. Ltd., R. G. Dingwall and M. Kriewaldt (1972) suggested the sediments underlying the Windellama limestone to be Silurian and those overlying the limestone of RUTH MAWSON ar Bs om spoos slow —— acu yan, bios JODNaaA auyouuy —— a ov WIMOLIIA sbuipjing 4 spoajseuoy Oo DIOS JO Dip PU aNVIS 10, — Saysop 1404ys Aq UMoYs Auopunog [0216ojoa ~—— Zoig vas * 3-4 UvoN2a5 ‘pajpaovo> asaym ! paianb ‘pasaju) asaym ‘uayo1g S| eull -, mOWNONddo Ss) SIN) B $P10)* SaOPUNOG jo UOIIOI0] Baym 940M K0)6 Thuonb£ ajoys * ajizjsONd ‘ auojs\jS* aUO)SpUOS AjlIS W é NWINNTIS QUOJSauI| SNosajI/IsSO4 PA Nvlunnis SAUOISIIS ‘Sauo|spUDS SNO@r0}jM) ‘SauoIspUDS {<)SNoar0yjn) ‘aud;spuDS fs 7 eno (parero> 0s) avoisawi) panaju) easy (sdojajno jonjo0) auojsewi| snosaji|19s04 [ow] f NVINOA3O ae (sdo12jno jonj20) sauojspuos snoarDjjnj ‘ Snosaji|isso} 351005 (wee) | N (sdoi9jno j0nj20) 44H snosayiissoj * aosewojbu05 Boog Soe Og (uipjyaoun 0) ajohyy [Fei] a ar 52016 ‘ spuos‘ auojspuos* ajosawojbuor * ajas>//S5 EG i fx $4U6 snosasiuobuoy ZZ | : os : vere > I0Z0NIv. ie 1, 5 ‘ : Suoisuou!* ayjvaio| © ayixnog FTE - ary 6 5 ¥ (auojsawi) UDUOAaG BulAjJeAO Auasoddo) 91)9\09 Ss - ‘Bs f WE v jis * jaAou * Aojo* puos * wnianiiy (=e) : . fi] 4 WS 'N | Vayuvy vwyaTadGNim Vy, ADO 1085 a | 614 fi: a THE GEOLOGY OF THE WINDELLAMA AREA, NEW SOUTH WALES possible Permian age. The fossils found in the latter, collected northwest of the main body of limestone by Dingwall, were submitted to Dr. J. W. Pickett (1972 unpub. report) who identified: Fenestella sp., Alveolites sp., Thamnopora sp., generically indeterminate ectoprocts and coelenterates, and a small ribbed brachiopod. He suggested possible correlation with early Late Devonian marine sandstones at Goulburn and Nerriga. Stratigraphy Sedimentary rocks of Silurian and Devonian age occur within the area (Figures 1 and 2). The Devonian sediments are bounded on the west by a fault (the Yarralaw Fault) trending approximately north-south ; a second inferred fault (the Jacqua Fault) marks their eastern and southern boundary. Overlying the Silurian- Devonian sequences is an extensive cover of Cainozoic sediments with, in one area, a minor veneer of loose ?Permian sediments, the latter being too limited in extent to be shown as a separate outcrop on Figures 1 and 3. Silurian The limestone that crops out in the south- western corner of the area mapped has been assigned a Late Silurian age on the basis of the presence of Conchidium or Kirkidium sp. The limestone is massive and jointed, but tends to dip steeply in a westerly direction. It is a compact limestone, somewhat dolomitized, dark grey to grey in colour, with scattered veins of calcite varying in thickness from 5 to 20 mm. Fossils from the limestone include : Conchidium or Kirkidium sp., and poorly preserved Favosites sp., Heliolites sp., large rugose corals, nautiloids, and abundant stromatoporoids. The outcrop of limestone in the northwestern region is of a similar age, as indicated by the presence of Conchidium or Kuirkidium sp., Favosites sp., gastropods and stromatoporoids. ‘Despite some alteration owing to its proximity to the Yarralaw Fault, this limestone is of similar lithology to the limestone outcropping in the southeastern corner of the area mapped. Sediments of Possible Silurian” Age The sediments cropping out in the south and east of the area consist of siltstones, argillaceous siltstones, shales, sandstones, quartzites, and cherts ; in places, micaceous siltstone and shale grade into phyllite. The beds are generally from 1 to 30 cm thick and in areas of pronounced folding are strongly cleaved. They form a series of folds, the fold axes being approximately \ S. ‘, S. ‘ Sane ‘, b% Ste 3 5 OSS . . Pett t Prt ube tld \ Tak a SS, \ “N ‘, 1500 METRES ? SILURIAN 4 Linvs wnoover “ 2 c = 2 a ae « c = ra v c ° * ” 3 3 oe S oS = 2 wn oe c 2 ra Zc = i=] a £& Z > r) eo S J = 2 ye e s = a a3 c S yn” ro o = =) ra c 2 ¢ E ° € = = a] = = n = =) [A Silty sandstone, silfsone, quartzite, shale,quortz, greywocke SSS Fossiliferous grits & sandstones Linvs MV TVEYVA Fig 2 Bedrock Structure from Junction of Windellama and Nerrimunga Creeks 285° to Popham’s Creek (F to E - see Fig!) 31 32 meridional, running slightly east of north. Dips generally range from 40° to 52°, but adjacent to the faults, especially the Yarralaw Fault, and in the less competent beds, they steepen con- siderably. They have been regarded as Silurian or Ordovician by previous workers in the area (Woolnough, 1909; Carne and Jones, 1919 ; Garretty, 1937; Naylor 1935a, 19350, 1937, 1939, 1949; Dingwall and Kriewaldt, 1972 unpub.). As no fossils have been recovered from these sediments in the area mapped, a positive age cannot be determined. Two factors suggest a possible Silurian age. Firstly, the limestones cropping out in association with similar terrigenous sediments in the west of the area are Late Silurian (see above). Secondly, the Devonian sediments immediately beneath the basal unit of the Windellama Limestone appear to be conformable with the underlying ?Silurian terrigenous sequence. If the latter were considerably older, one might expect discordance in dips and differing style of deformation. No sequence transitional from these sediments to the Devonian sediments has been observed. Early Devoman The lower part of the sequence consists of a series of sandstones, tuffaceous(?) sandstones, and siltstones. These are followed by fossilifer- ous limestones, and these in turn by fine tuffaceous sandstones, coarser tuffaceous sand- stones, grits and conglomerates. These sediments can thus be divided into three units : 1. the sediments underlying the Windellama Limestone; 2. the Windellama Limestone ; 3. the sediments overlying the Windellama Limestone. A group name could therefore be introduced with three constituent formations, but no formal nomenclature is proposed in advance of more extended regional mapping. Use is however made of the name Windellama Limestone, as the name first introduced formally by Pickett and Huleatt (1971), for the prominent development of highly fossiliferous carbonates. The beds of the entire sequence strike in a direction a little east of north, and are gently folded. Approaching the Yarralaw Fault the folding becomes more intense, beds dipping at angles up to 70° (Figures 1 and 2). (i) The Lower Umit South of the junction of the Limestone and Windellama creeks, where the extension of the Jacqua Fault becomes uncertain, is a series of fine-grained thinly bedded sandstones, inter- bedded occasionally with siltstones. Beds range RUTH MAWSON in thickness from 4 to 24 cm. The sandstones — grade into fine tuffaceous(?) sandstones. Fossils found at localities 188, 198, and 202 (loose) § consist of Howellella sp., other but indeterminate § brachiopods, corals, and crinoid stems. The ~ relationship of this lower unit to the ?Silurian ~ sediments to the east is obscure. Because of — poor outcrops and abundant soil cover the § Jacqua Fault cannot be traced through the area, — but the sediments of the lower unit are decidedly — more sandy and not so shaly as the underlying | ?Silurian sequence. It could be that there was § no decided break in sedimentation between the § two. (ii) The Windellama Limestone The Windellama Limestone crops out from the junction of Windellama and Limestone Creeks } along the Windellama Creek to Burburba home- 50 100 ~~ | Alluvium, sand, clay, —— gravel Bsilt 3 PE be cm Bauxite, laterite, ironstone ie Basalt Sea Pa . a Se ES Manganiferous grits By ae i ° ° °o 20 Silctete, conglomerate sandstone, sands, gravels ossiliferous limestone octual outcrops Inferred limestone ( soil covered ) Sandstones tuffaceous (?) sandstone} © siltstone, shale Silty sandstone, siltstone, quartzite shale, quartz, greywacke 3. Detail of limestone outcrops along Limestone Creek Fig stead (Figure 4). The major outcrop occurs on ye Limestone Creek in the vicinity of a disused © quarry approximately 200 m north of the junction of Windellama and Limestone creeks (Figure 3). ; As far as one can tell from the limited outcrops, | the limestone is conformable with the under- — lying sediments, but no actual outcrops demon- strate transition to or contact with the lower — unit. Such a transition or contact is obscured — by a cover of alluvium for a distance of only — THE GEOLOGY OF THE WINDELLAMA AREA, NEW SOUTH WALES 33 Silcrete, conglomerate, sandstone, sands, gravels [ow | Fossiliferous limestone (actual outcrops) er Inferred limestone ( soil covered ) METRES Kar Silty sandstones,siltstone, quartzite , shale, quartz, qreywocke ‘Burburbo i pomesees LN [ ‘ felts 71a MiLd Vea a? Ta Sad ed Ts , | from 3-5 to 4 m at the base of the limestone on » |) the north side of Limestone Creek a little to the ® feast of its junction with Windellama Creek. The total thickness of limestone is at least ' 283m. The lowermost limestone is dolomitized . and richly fossiliferous. Veins of varying i" thickness and splashes of calcite are common. www, Algae and stromatoporoids are the predominant wt, i fossils of the limestone at this level, but there is a notable change in fauna up the sequence. i | Algal material gives way to corals, both tabulate J and rugose ; brachiopods are also present. —{} Up the section the limestone becomes less dolomitic, more compact, well-bedded and —# silicified. This limestone is again richly fossil- { ) iferous, but the fauna consists almost entirely of corals, principally tabulates. Some | | stromatoporoids are to be found, but there is a / complete dearth of brachiopods. Exposures are good in the vicinity of the | Quarry on Limestone Creek ; here well-bedded, RY f highly fossiliferous black micrites in beds from he | 2 to 20 cm in thickness have three developments vals OL, Silicification: the lowermost (11-4 m in ") thickness) occurs 125 m above the base of the || limestone, the second (1-4 m in thickness) occurs 10) | 171 m above the base of the limestone, and the ie) topmost (4-2 m in thickness) occurs 180 m above nol | the base of the limestone. oi!) The highest beds of the Windellama Limestone cu appear to be the massive dark grey to black only | — a Sandstones, tuffaceous(?) sandstones, siltstones Fig 4. Detail of limestone outcrops along Windellama Creek limestones found at the creek crossing at Burburba homestead. These are less richly fossiliferous, and are extensively veined by calcite. North of the Windellama Church, there is a flat with outcrops of calcrete that may be connected with yet higher horizons of limestone not known in outcrop. The following conodonts have been extracted from the topmost development of silicified beds : Ambalodus aff. galerus, Belodella sp. devonica, Hindeodella equidentata, H. priscilla, Icriodus woschmidti, Ligonodina diversa, L. elegans, L. salopia, L. silurica, Lonchodina cristagallz, L. greilingt, L. walliserit, Neoprioniodus bicurvatus, N. excavatus, N. multiformis, Ozarkodina denckmanni, O. media, O. australis, Paltodus acostatus, P. wumicostatus, Plecto- spathodus alternatus, P. extensus, P. flexuosus, Spathognathodus canadensis, S. exiguus philipi, S. remscheidensis, S. steinhornensis optimus, S. wurmi, Trichonodella excavatus, T. inconstans, T. symmetrica, T. symmetrica pinnula. The identifications were kindly checked by Dr. G. C. O. Bischoff, Macquarie University. The presence of the conodont JIcriodus woschmidtt among the fauna dates at least this part of the section as Lochkovian (cf. Savage, 1973 ; Link and Druce, 1972). The remainder of the fauna is consistent with this age assignment. 34 RUTH MAWSON (ii) The Upper Unit No direct contact between the Windellama Limestone and the _ overlying Devonian terrigenous sediments has been observed because of Cainozoic cover. Approximately 800 m north and slightly to the west of the junction of the Windellama and Limestone creeks (locality 218) there are fine grained fossiliferous silt- stones, sandstones and tuffaceous sandstones. Similar lithologies and fossils occur at localities 32, 42, 45, 47, 60, 81, 91, 93, 102, 110, 112, 126, 133, and 167. The fauna of these sediments consists of Howellella sp., Aulacella sp., and other but indeterminate brachiopods, Pleurodictyum megastoma, Cladopora cf. corrigia, Syringaxon sp., Fenestella sp. nov. cf. F. dargoensis, inde- terminate trepostome bryozoan, crinoid stems, Koneprusites sp., Acanthopyge australis, Leonaspis sp., Chetrurus (Crotalocephalides) gaertnert (Alberti), Phacops sp. and scutelluid trilobites. The presence of C. (C.) gaertnert (Alberti) dates these sediments as_ Early Devonian (Praguian). The fine tuffaceous sandstones give way to a series of coarser fossiliferous tuffaceous sand- stones that are best exposed in the northeast part of the area. In places, expecially at locality J1, the tuffaceous sediments show spheroidal weathering. Fossils found in this material at localities 3 and 27 include: Howellella sp., other orthid, spiriferid and rhynchonellid brachiopods, bryozoans, crinoid stems, rugose and tabulate corals. Above the coarse tuffaceous sediments a series of poorly cemented, coarse-grained sand- stones, grits and conglomerates containing pebbles of quartzite and clasts of clay is found. Fossils collected earlier by R. G. Dingwall of Asarco (Australia) Pty. Ltd. from coarse weathered sandstones about 1:5 km N.W. of Burburba homestead were thought to be possibly Late Devonian in age (Pickett, 1972) but the presence of the fossils listed above, particularly the trilobites, including Cheirurus (Crotalocephalides) gaertneri (Alberti), from locality 218 where these deposits are im situ, confirms an Early Devonian age. Faunas similar to those from locality 218 and those collected by Dingwall have been found at localities 46 and 134. ? Permian Immediately overlying the outcropping lime- stones on the left bank of Limestone Creek (locality 213) and also to a lesser extent on the right bank (locality 126), are blocky siltstones containing generally fragmentary Devonian upslope by laterites here regarded as probably } 3 Tertiary in age. The fossiliferous Devonian } Bu rocks are however, problematic. Blocks almost } al a cubic metre in size are present and conceivably | mi still larger blocks may be buried; none of the } Wi material whatever shows evidence of rounding } ty —all blocks are angular but much of this } do angularity is presumably due to breakup along joint planes during weathering. It seems probable that this material has been transported, | 7 possibly from the north from the area where ] } outcrops of similar material are known, and } », spread out as a veneer across the truncated ] ,, edges of the Devonian limestones, possibly hed during Permian times. / ID ston Cainozoic | ver Much of the area is capped by Cainozoic rocks : conglomerates, sandstones, grits, laterite” and bauxite, silcrete, manganiferous grits and basalt, deep weathered remnants of a formerly | vast sheet of sand, gravels and minor basalts. | thn The Tertiary sandstones are flat-lying, quartz | shot arenite beds consisting predominantly of quartz | ime grains with a few quartzite and shale fragments | we scattered throughout. Grain size ranges from } ,., fine to very coarse sand; sorting is usually | 1:3 poor; sub-rounded' grains _ predominate, |, Because of poor consolidation, the sandstone } ,,. readily weathers to sands and gravels. The) manganiferous grits consist of sands and gravels }} cemented by a ferruginous and manganese-rich | cement. The grains are predominantly sub-) angular to sub-rounded, and are very poorly) sorted. Some investigation of these has bee made as regards their commercial value. The conglomerate that crops out in two isolated) localities, 145 and 157, has angular to rounded clasts of up to 25 cm in diameter set in a fine) matrix. . A small outcrop of Tertiary basalt oc adjacent to a large outcrop of silcrete north-west} of the junction of the Windellama and Limestone} creeks. In this section it can be recognized as an alkaline olivine basalt containing clusters of olivine phenocrysts. Pinkish mauve titanifer- ous pyroxene is present, and the plagioclase is arranged subspherulitically. Needles and] 4 anhedra of opaque minerals and _ interstitia zoned plagioclase are also present. Silcrete, laterite and bauxite deposits, derived from the weathering of older rocks and o: Tertiary basalt, crop out frequently in the area. = =e THE GEOLOGY OF THE WINDELLAMA AREA, NEW SOUTH WALES Red to brown pisolitic ironstone weathers to produce a very distinctive pavement of spherical nodules about 5 mm in diameter. Vermiform laterites are common. Between the Windellama Church and Burburba homestead there is a large deposit of calcrete, presumably derived from Devonian rocks, possibly the topmost horizons of the Windellama Limestone. Calcrete has also developed on some of the limestone outcropping along Windellama Creek to the northeast. Structural Features The fold pattern of the Silurian and Devonian | bedrock is shown on Figures 1 and 2. The fold axes strike slightly east of north. Dips average about 46°, but to the west the dip of the thinly- bedded, strongly cleaved shales and fine sand- stones increases sharply and in places near vertical bedding can be observed. The patchiness and paucity of outcrop make the establishment of faults in the area difficult ; two major faults are however, inferred: a NNE trending fault in the west of the area along | which the Devonian sequence has been down- thrown against a demonstrably Silurian section ® shown to contain two lenses of fossiliferous limestone of Late Silurian (probably Ludlovian) age. This fault appears to be the southward extension of a fault shown on the Goulburn 1: 250,000 sheet (Brunker and Offenberg, 1970) as separating Late Devonian sandstones on the ® east from an Ordovician flysch section to the west ; Brunker and Offenberg (1970) show this fault extending almost to Yarralaw Creek. The presently mapped fault, obviously an extension of Brunker and Offenberg’s fault, has been here named the Yarralaw Fault. The Devonian sequence is noticeably more arenaceous than the ® typically shaly Silurian sequences to the west. @the rhyolite. The intrusion of a prophyritic devitrified ® rhyolite that crops out in the NW corner of the mapped area may have been related to the fault. The rhyolite contains large feldspar fragments, peatz, and very altered spherulitic amphiboles. A very fine-grained red “ quartzite ’”’, consisting of at least 90 per cent quartz, lies adjacent to It is apparently the altered (product of the country rock. Large outcrops of quartz near the postulated junction of the ® two faults give further indication of a fault. Owing to poor outcrops a second fault, the i Jacqua Fault, cannot be picked up with precision on the ground but is inferred from the mapping. vay Mapping of the Windellama Limestone (Figure 1) shows that southwards along strike the lime- #mstones are consistently replaced by unfossilifer- 35 ous shaly and sandy sediments thought to be of Silurian age, a relationship consistent with NE trending fault in this area. Towards the NW, where it would lie within generally poorly out- cropping shales and sandstones (towards the eastern boundary of Figure 1) the position of the fault is uncertain. Similarly, the extension of the fault westward becomes speculative because of the widespread cover of Cainozoic sediments and the virtual absence of outcrop away from Windellama Creek. Almost due east of Burburba homestead, along the line of the fault, a typical fault breccia exhibiting slickenside crops out and can be traced for about 50 to 70 m along the fault line. Loose reef quartz abounds along the line of the fault S and SE of Burburba homestead. The area about and south of the junction of Limestone and Windellama creeks presents some problems in interpretation. A small, more or less E-W tear fault is evident, deduced from the lateral displacement of the basal beds of the limestones. On the north side of Limestone Creek these are displaced eastwards about 125 m relative to the basal limestone on the south side of the fault ; the limestones on the north side therefore give the appearance of being replaced southward along strike by sandstone. The fault may be a small right lateral wrench fault. Acknowledgements I am grateful to Dr. J. W. Pickett of the New South Wales Geological Survey for his practical advice and encouragement, to Asarco (Australia) Pty. Ltd. for making available R. G. Dingwall and M. Kriewaldt’s report on the area, to the graziers of Windellama for allowing me access to their properties, and to Dr. J. A. Talent and other colleagues in the School of Earth Sciences, Macquarie University, for their kindness and forebearance when confronted with assorted technical and academic problems. References Baker, R. T., 1909. Building and Ornamental Stones of New South Wales. Technical Education Series No. 16, Sydney. BrunNKER, R. L., and OFFENBERG, A. C., 1970. Goul- burn 1: 250,000 Geological Series Map Sheet SI 55-12, Geol. Surv. N.S.W. CaRNE, J. E., and Jones, L. J., 1919. The Limestone Deposits of New South Wales. Min. Res. Geol. Surv. N.S.W., 25, 411. CLARKE, Rev. W. B., 1860. Researches on the Southern Gold Fields of New South Wales. Reading and Wellbank, Sydney, 305. DInGwaLlt, R. G., and KRIEWALDT, M., 1972. Final Report on Exploration Licence No. 279, Goulburn, N.S.W. Asarco (Australia) Pty. Ltd., Adelaide Office Report No. 60 (unpub.). 36 GarreTty, M. D., 1937. Geological Notes on the Country Between the Yass and Shoalhaven Rivers. Jour. Proc. Roy. Soc. N.S.W., 70 (2), 364. Link, A. G., and Druce, E. C., 1972. Ludlovian and Gedinnian Conodont Stratigraphy of the Yass Basin, New South Wales. Bur. Min. Res., Geol. Geophys. Bull., 134, 136. Naytor, G. F. K., 1935a. Note on the Geology of the Goulburn District, with Special Reference to Palaeozoic Stratigraphy. Jour. Roy. Soc. N.S.W., 69, 75. Naytor, G. F. K., 19356. The Palaeozoic Sediments near Bungonia: Their Field Relations and Graptolite Fauna. Jbid., 69, 123. Naytor, G. F. K., 1937. Preliminary Note on the Occurrence of Palaeozoic Strata near Taralga, N.S.W. Ibid., 71,.45. Naytor, G. F. K., 1939. The Age of the Marulan Batholith. Jbid., 73, 82. School of Earth Sciences, Macquarie University, North Ryde, N.S.W., 2113. RUTH MAWSON Naytor, G. F. K., 1949. A Further Contribution to the Geology of the Goulburn District, N.S.W. Ibid., 83, 279. PickETT, J. W., 1970. Macrofossils from the “Windellama’”’ Limestone. Rep. geol. Surv. N.S.W., GS 1970/284 (unpub.). Pickett, J. W., 1972. Marine Fossils from Sandstones at Windellama. Rep. geol. Surv. N.S.W. Pal. Report No. 72/2 (unpub.). PickEeTT, J. W., and Huveatt, M. B., 1971. Age of the Windellama Limestone. Geol. Surv. Quart. Notes, No. 2, 1. SavaGE, N. M., 1973. Lower Devonian Conodonts from New South Wales. Palaeontology, 16 (2), 307. Woo noucnH, W. G., 1909. The General Geology of Marulan and Tallong, N.S.W. Proc. Linn. Soc. N.S.W., 34, 782. (Received 5.6.74) Slahasncantondigatis — Jou Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 37-51, 1975 The Merrimbula Group of the Eden-Merrimbula Area, N.S.W. J. STEINER Communicated by K. A. W. Crook ABSTRACT—The Upper Devonian Merrimbula Group is divided into three formations and represents a coarse red-bed succession which contains a finer-grained, drab sequence in the middle. The basal 90 m red-beds are termed the Twofold Formation. The middle drab sequence and the upper red-beds are defined as the 350 m Bellbird Creek and 430 m Worange Point Formation respectively. The Twofold Bay Formation records the deposits of a northerly sloping alluvial fan which was built up by a braided stream system and grade into the deposits of small meandering streams at the top. The lower Bellbird Creek Formation represents a marine transgression consisting of barrier island, littoral and shallow marine facies which are overlain by subaqueous deltaic deposits. During Bellbird Creek time the palaeoslope dipped toward the southeast with a southwest-northeast shore-line trend. The upper Bellbird Creek Formation consists of tidal flat deposits with some windblown dunes and lagoon deposits at the top. Average palaeotidal range may have been of the order of 4:6 m. During Merrimbula time palaeowind direction was toward the north. The Worange Point Formation records the deposits of a coastal plain, meandering river belt with the palaeoslope dipping gently toward the south-east. The basal Worange Point rocks probably represent subaerial, top-set deltaic beds. The Worange Point meander belt may have had a width of 2:6 km and the channel depth may have been characterized by a normal low water stage of 4 m and a maximum flood stage of 17 m. Clay mineralogy possibly “ Middle or Yalwal indicates a palaeoclimatic warming-up trend during Merrimbula time. Introduction In the Eden-Merrimbula area Upper Devonian Merrimbula Group rocks outcrop over a large area (Figure 1) (Hall, 1969). The rocks have been folded during the Kanimblan orogeny in early to mid-Carboniferous time (Hill, 1967). The Merrimbula Group is divided into three formations (Table 1), (Steiner, 1972) and represents a coarse red-bed succession which contains a finer-grained, drab sequence in the middle. This report summarizes a detailed stratigraphic and environmental study of the Merrimbula Group (Steiner, 1966) which is based on several sections (Figure 2) recorded TaBLE 1 Stratigraphy Brown (1931) Hall (1957) Merrimbula “ Formation ”’ (Upper Devonian) “ Upper or Lambie Stage ”’ Wolumla Conglomerate Member Lochiel Formation Stage ”’ (Upper Devonian) “ Lower or Eden Eden Rhyolite Stage ”’ (Middle Devonian) Un-named (Upper Ordovician) Un-named (Ordovician ?) Steiner (1966) Worange Point Formation Merrimbula Group Bellbird Creek Formation Twofold Bay Formation Wolumla Conglomerate Member Lochiel Formation Cusack Creek Member Eden Rhyolite (Middle or Upper Devonian) Quarantine Bay Member Mallacoota Beds 38 J. STEINER 149°40" gras" 149°50' 1a9°SS wou Lin Cn Om. Oz OZ T \ S WZ F « aS: [JTertiary and Quaternary : ‘s MM >-Worange Point Formation EEA] o-Bellbird Creek Formation [QQ o»-Two Fold Bay Formation ES3Joum—-Merrimbula Group VUZZA>-l-Lochiel Formation EZ Jore-Eden Rhyolite - Middle to Upper Devonian W7--Mallacoota beds - Ordovician [Fs *]00b-Bega Granite > JS1-Stratigraphic Sections Upper Devonian rm x Sp . NP NC 37 00" kilometers YY ‘ama i i Rat | 2 3 miles 149°45° FIGURE 1.—Geological map of the Eden-Merrimbula area, N.S.W. $4 THE MERRIMBULA GROUP OF THE EDEN-MERRIMBULA AREA, N.S.W. GROUP MERRIMBULA Two Fold Ba Worange Point Formation Bellbird Creek Formation Y Formation Worange Point (cont.) JS8 =| Shale C Siltstone ba eterna A Pg rtzoze sandstone Shale ‘last conglomerate Ps Gon lomerate onglomeritic sandstone feet ining upward cycle 800 Rhyolite *.*.* Granite — oor exposure ae oe interval ba bey a 600 = Worange Point +— JS4 a 400 as = Ss a be = 2] | feet Te 1-600 >< Wolumla Peak ee ec after Eo Hall, 1957 a = | Edrom a 0 = JS 12-13 be feet 200 P| ss > — = Rite a = = FAULT a eso 800 WHITE rig : 600 es =a Wr a ra i wo ssat-400 a z he Pai Pi 4-200 = i=] CONGLOMERATE _ MEMBER Ficure 2.—Correlation of Sections. meters 700 600 500 450 400 350 250 150 100 39 40 and measured by the Bouma (1962) method and thin-section analysis. A total of 426 units (Figure 3) and 210 thin-sections have been described in detail, which represent approx- imately 800 m of the Merrimbula Group. Hill (1967) summarized the macrofauna and age of 140 120 80 60 40 N __Onumbers 9 30 40 5060 3 4 51678910 20 meters : 03 05 ] 2 3 4 °5 678910 15 FIGURE 3.—Measured thickness versus number of sedimentation units. the Merrimbula Group and a preliminary report on the palynology is included as an appendix here. The basal 90 m of red-beds of the Merrimbula Group are designated Twofold Bay Formation which locally unconformably overlies the Eden Rhyolite, the Mallacoota Beds, and the Bega J. STEINER Granite, but appears conformable with the underlying Lochiel Formation (Steiner, 1972). The Wolumla Conglomerate Member, as defined by Hall (1957) is at the base of the Twofold Bay Formation. The section JS1 (Figures 1 and 2) is designated the type section of the Twofold Bay Formation. The top of the Twofold Bay Formation is defined by the uppermost 1 to 1-5 m brick red mudstone horizon. The middle 350 m of drab beds of the Merrimbula Group are termed the Bellbird Creek Formation, which conformably overlies the Twofold Bay Formation. The base of this Formation is defined by the top of the Twofold — Bay Formation or the lowermost green or — greyish mudstone or shale in access of 1 m. The transitional contact between these two formations is locally characterized by red, green, and brown mudstone lenses of outcrop scale. The top of the Bellbird Creek Formation and — the base of the overlying Worange Point Formation is marked by apparent, multiple erosional contacts which are termed a paracon- formity (Dunbar and Rodgers, 1967). This boundary is characterized by a colour change from the drab or green finer-grained beds of the Bellbird Creek Formation to the coarser red or reddish brown beds of the Worange Point Formation. by scours and an abundance of nests of cobble and pebble-sized red and green mudstone or shale clasts. In discussing the Bellbird Creek Formation it is informally between the upper and lower Bellbird Creek Formation whose type sections are respectively JS12 and JS4 (Figures 1 and 2). The upper red-beds of the Merrimbula Group (Figure 2) are the 430 m plus of the Worange Point Formation whose base is given by the top of the Bellbird Creek Formation but whose top remains undefined. The sections JS4 and JS8 serve as type section of the Worange Point Formation (Figures 1 and 2). TABLE 2 Percentage Lithologies—Merrimbula Group Conglomerate 0 Worange Point Formation SE ye 6 Upper Bellbird Creek Formation os 0 Lower Bellbird Creek Formation si 10 Twofold Bay Formation. . 30 The erosional surfaces are marked convenient to distinguish 7 Sandstone Siltstone Cover % Peete % % 70 7 16 1 48 ll 27 14 | 57 7 i 22 4 19 10 | 36 5 52 9 | 23 5 Merrimbula Group 3 oe “i 11 THE MERRIMBULA GROUP OF THE EDEN-MERRIMBULA AREA, N.S.W. 41 TABLE 3 Colour Statistics of Merrimbula Group Lithology Worange Point Formation .. | Conglomerate Sandstone Sh. and sltst. Bellbird Creek Formation Conglomerate Sandstone Sh. and sltst. Total Twofold Bay Formation Conglomerate Sandstone Sh. and sltst. Total Merrimbula Group Total wa Merrimbula Group lithology : The sections measured along the coastline (Figure 1 and 2) have 95 per cent outcrop. The percentages of lithologies of the Merrimbula Group are summarized in Table 2. The group is characterized by a high conglomer- ate (11 per cent) and low shale content (37 per cent). A breakdown of the percentage lithologies by Formation indicates that most of the pebble and boulder conglomerate is con- tained in the Twofold Bay Formation and its basal Wolumla Conglomerate Member (30 per cent). The poor sorting of Twofold Bay Formation is reflected in its low sandstone content (19 per cent). The conglomerate con- tent of the lower Bellbird Creek Formation (10 per cent) represents granular conglomerate or quartzose grit. The upper Bellbird Creek Formation lacks conglomerate and is nearly evenly split between sandstone and shale plus siltstone. The Worange Point Formation has a high sandstone content (70 per cent) and low content of fine-grained sedimentation units (24 per cent). Colour: The fresh and weathered colour of each of over 400 sedimentation units was obtained by comparison with the Rock Colour Chart of the Geological Society of America (1951). These fresh colour determinations are tabulated in Table 3. The Merrimbula Group as a whole is characterized by 39 per cent of the sedimenta- Red Hues Drab Hues —_———_— Reddish- —_ Purple Red Brown | Brown | Green | Grey or va ye % % % Whitish % 39 32 1 27 1 0 23 23 3 45 6 0 2 98 0 0 Trace 0 19 42 2 33 + 0 0 0 33 4 8 55 4 3 34 29 21 9 0 2 9 12 78 0 2 2 25 21 39 11 48 26 0 11 13 2 27 45 2 20 2 4 40 51 0 1 6 2 40 4] Trace 8 8 3 tion units of red hues, 12 per cent of reddish- brown, and 49 per cent of drab hues. However, if the breakdown is done by formations and lithologies the following characteristics emerge. In the Twofold Bay Formation, 74 per cent of the conglomerate units, 72 per cent of the sand- stone units, and 91 per cent of the shale and siltstone are red (Table 3). With regard to the TABLE 4 Colour Modes per Lithology of the Merrimbula Group Unit Colour Mode % Twofold Bay Fm. : Conglomerate Red and purple 73 Sandstone Red and purple 71 Minor brown 22 Shale and siltstone | Red and purple 91 Bellbird Creek Fm. : Conglomerate Grey or white 56 Reddish brown and brown 37 Sandstone Reddish brown and brown 63 Minor green 21 Shale and siltstone | Green 78 Worange Point Fm. : Conglomerate Red and purple -70 Minor brown mode 27 Sandstone Red and purple 46 Brown 48 Shale and siltstone | Red 98 42 Bellbird Creek Formation 67 per cent of the conglomerate units are white or drab, 50 per cent of the sandstone units are drab and 78 per cent of the shale and siltstone units are green. In the Worange Point Formation 71 per cent of the conglomerate units, 46 per cent of the sandstone units, and 100 per cent of the shale and siltstone units are red (Table 3). The colour modes of the Merrimbula Group per lithology are sum- marized in Table 4 and clearly indicate oxidizing conditions for the deposition of the Twofold Bay ; TABLE 6 Summary “of Cross- Stratification Modes Azimuthal mode 1 .. (aqueous) Vector sum: N359°E, stand- ard deviation 10° Twofold Bay Fm. Dipmodes: 12-5°, conglo- merate, planar, small scale 17-5°, sandstone, simple, large and small scale 22-5°, conglomerate, simple, large and small scale Aeolian mode Approximately due north Merrimbula Group | Dip modes: 32-5°, sandstone, planar, large scale 32-5°, mainly granular con- glomerate, planar, small scale Azmuthal mode 2 .. (aqueous) Bellbird Creek Fm. Vector sum: N61°E, standard deviation 23° Dip modes : 7:-5°, sandstone, small scale 12-5°, conglomerate, planar, large scale 22-5°, granular conglomer- ate, simple and trough, small and large scale Vector sum: N133°E, stand- simple, Azimuthal mode 3 (aqueous) ard deviation 18° Bellbird Creek and | Dip modes: Worange Point 12-5°, sandstone, simple and Fm. planar, small and large scale, slumped _ cross- stratification* 22-5° conglomerate, simple, small scale 25°, sandstone, planar, large scale, slumping* *48 cross-stratification reading were taken of slumped cross-laminations. and Worange Point Formations and more reducing conditions for the Bellbird Creek Formation, Cross-stratification : Cross-bedding is common in the Merrimbula Group rocks and a total of 543 cross-bedding directions have been taken. A rose diagram of 217 Merrimbula Group cross-bedding shows three azimuthal modes (Figure 4). Mode 1 is a strong northerly mode, J. STEINER while Modes 2 and 3 are north-easterly and south-easterly respectively. The modal vector sums, modal standard deviations, and cross- bedding characteristics of these modes are summarized in Table 5 which utilizes terminology of McKee and Weir (1953). The three modes are strongly dependent on stratigraphic position, as shown in a series of 26 cross-bedding rosettes plotted every 30 m for Mode 1. vector sum Mode 2. vector sum Mode 3. vector sum 4.—Cross-stratification of Merrimbula Group FIGURE the 800 m of the Merrimbula Group (Figure 5, column 4). The 26 rosettes incorporate twice the cross-stratification readings since a 50 per cent stratigraphic overlap is employed in plotting the rosettes. Cross-bedding rose diagrams for each formation also show that the three modes are characteristic of one or two of the Formation (Figure 6). Mode 1 is typical of the Twofold Bay Formation. The Bellbird Creek Formation is characterized by Modes 2 and 3 and a subsidiary mode 180° from Mode 2 is also present. The trends of ripple marks of the Bellbird Creek Formation are either parallel or perpendicular to Mode 2. The Worange Point Formation yields cross-bedding directions oo mipeateean a ce Ow. Formation er en ee 43 THE MERRIMBULA GROUP OF THE EDEN-MERRIMBULA AREA, N.S.W. \, ae H ore “ . . uolyeoylzeI}s-sso1o pue ASojosjed ArequsuIpos—'‘e aAANdLT [sea ST os AYWINSWIGAS 38 E GalsILN3GINN 2 DINVIOA USHIOx fa}; DIHGYOWVISW x f5] ISSN VED) TWASNIW AVID » BS3_INIWID =? (P32) ZLVNO 3 XIMLVW se 2 YVdSAT34 5¢ 2 Soe SSeS 2 SOS SOOO OSS > RSOSSeSOSOCIOSO SOP BSSSOSSCSOSOS SSS OS SD : SSOSOSSESOSOSSCS OOS PSSSoS SSS SOSOS SOS SESS CSS SLNSWOVAS #9 PS VOI: 3% 3 ZLYWNO 2 & SININOdWOD ye? WOM 3Wved ~ § “SS eS) OS a i i ee TN Ve CB Cay Won el Ct Eis Doe Gace SSE SSSA SS a SSS eM cee ee SS ee Pe 44 J. STEINER of Mode 3 (Figure 6). The cross-stratification data yield the following conclusions : Paleoslope direction was toward the north during Twofold Bay time and toward the southeast during Worange Point time. During Bellbird Creek time the paleoslope was also dipping toward the southeast with the shoreline trended southwesterly to northeasterly. The details of the cross-bedding and granularmetric analyses (Steiner, 1966) suggest a palaeowind direction from south to north (Table 5). Seventy four per cent of the aeolian strata contain some red pigment and range in colour from purple to red and brown (Table 6). Other directional data such as channel direction (23 readings), directions of thinning and lensing of coarse clastic units (28 readings) and trends of ripple marks (40 readings) are in general agree- ment with the palaeocurrent conclusions based on cross-stratification. Crook (1967) utilized these palaeocurrent directions in interpreting the regional Upper Devonian palaeogeography. Direction of transport and colour: For this purpose it is convenient to group purple, red, reddish-brown, and brown interbeds as “‘ red pigmented ” strata and green, grey and whitish ones as “‘ neutral” strata of these terrigeneous Merrimbula Group rocks. In the Twofold Bay and Worange Point Formations the vast majority of sedimentation units contain red pigment and therefore the units with down- palaeoslope cross-bedding are also red to brown. However, the colours of the Bellbird Creek Formation has both a terrestrial down- slope and a longshore source (Figure 6), as indicated by equal proportions of red-pigmented (50 per cent) and neutral strata (50 per cent) be roughly a function of the colour of the source material, the transportation history, and redox potential of the final environment of deposition (Table 3, 4, 6). Down-palaeoslope current directions are associated with sedimentation units consisting of 75 per cent “ red pigmented ”” Worange Point Formation Bellbird Creek Formation Twofold Bay Formation FIGURE 6.—Cross-stratification by Formation. strata and 25 per cent of strata of neutral colours. Current direction parallel to the palaeoslope are associated with units comprising 45 per cent “red pigmented ”’ strata and 55 per cent inter-— | beds of ‘“‘neutral’’ colour. For the up- and down-palaeoslope directions the proportions are TABLE 6 Colour Statistics and Current Direction of the Bellbivd Creek Formation Red Pigmented Strata Neutral Strata -——— qe qaq— |_q“c—— y nemo —§.- eh io, 2 a eee "Cabs SIE CAI Gori ee ee ee } eS ee Oe Oe Oe (Table 6). Colour of the strata is shown to Footage Current Direction of Total | Red and | Reddish- Grey or we Purple brown Brown Green White % % % % % Down-palaeoslope a a3 Sa 30 8 16, 51 19 6 Down-and up-palaeoslope 3 aN 14 0 39 24 37 0 Parallel to palaeoslope .. ce a 44 0 32 13 26 29 Current direction not known .. xt 12 4 4 18 48 26 Total Bellbird Creek Formation 100 4 25 21 39 11 Aeolian component Minor 55 19 26 0 45 THE MERRIMBULA GROUP OF THE EDEN-MERRIMBULA AREA, N.S.W. UOIYDUIOJ jUlOd Sic 2) Ww UOYOWIO, 48817, Pulgyjeg saddy ar UOIOUIOY Ang | PIO4 OM Ite lox on ent 10n i 4 ) / tion a\1uasD B}\go|-qns 14h} soayidaso a]IGo] JiWodspjay eldspato-lithic arenite ithofeldspathic arenite ajiUaiD asozyorb \/ 5S 2s = 2 94{1U8s a}Iqo) 46 63 per cent “red pigmented ”’ and 37 per cent “neutral ’’ strata (Table 6). These percentages are interpreted to indicate that the red pigment originated up-palaeoslope and after transport to the paralic environment of deposition of the Bellbird Creek formation was _ progressively reduced. Sedimentary petrology: The textural details of the sedimentation units of the Merrimbula Group are schematically shown in Figure 2. Crook’s (1960) classification of arenites is utilized for the sandstones of the Merrimbula Group (Figure 7a). The Lower Twofold Bay For- mation, including the Wolumla Conglomerate Member, consists of lithic sandstone, while the upper Twofold Bay Formation units are pre- dominantly feldspatho-lithic sandstones (Figure 7b). The lower Bellbird Creek Formation includes two distinct interbedded lithologies which on the QFR diagram (Figure 7c) cover areas which are roughly equal to the fields of sublabile sandstone and lithic labile sandstone respectively. The upper Bellbird Creek and Worange Point Formation units consist exclusively of lithic labile sandstone (Figure 7d and 7e). The point-count data and the more detailed mineralogical and petrological identifications are also plotted in log form (Figure 5) for the Merrimbula Group and may be summarized as follows. The framework components (pheno- clasts), vary between 63 per cent and 88 per cent indicating fair to good sorting (Figure 5, column 5). The extremes of sorting are more typical of the lower Bellbird Creek Formation. The percentage quartz generally varies between 40 per cent and 60 per cent of total (Figure 5, column 6), but quartz content is low in the Wolumla Conglomerate Member (10 per cent— 45 per cent) and high in the lower Bellbird Creek Formation (75 per cent). Major unstable components (feldspar and rock fragments) vary around 30 per cent +10 per cent and remain fairly constant throughout the Merrimbula Group except in the Wolumla Conglomerate where they reach 80 per cent (Figure 5, column 8). The matrix content (Figure 5, column 11) is variable according to sorting, but is generally low in the high-energy lower Bellbird Creek units. The silica and clay cement content is summarized in Figure 5, column 12 and silica cement is very high (maxima 25 per cent) in the quartzose granular conglomerates and sandstones of the lower Bellbird Creek Formation. The clay mineralogy of the fine-grained units of the Merrimbula Group has been determined J. STEINER by the Conolly (1965) method. Kaolinite content varies from zero to 44 per cent and illite content from 56 per cent to 100 per cent. The average kaolinite content is increasing and illite content is decreasing up-section (Table 7). A similar average upsection kaolinite increase — can be deduced from Conolly’s (1965) data of © the Hervey and Cocoparra Groups of the Upper — Devonian rocks of the central and western province of New South Wales (Table 7). Although the kaolinite content is largely a function of provenance, the average up-section kaolinite increase may be interpreted as a TABLE 7 Clay Mineralogy of Merrimbula Group Illite Kaolinite Worange Point Fm. . 75-5% 24-5% (2 samples) ‘ Bellbird Creek Fm. .. 84-7% 15-3% (5 samples) Twofold Bay Fm. 94-5% 5:5% (4 samples) ‘ Clay Mineralogy of Hervey and Cocoparra Group Tllite Kaolinite Worange Point Fm. equivalent | 53-7% 46-°3% ( 8 samples) Bellbird Creek Fm. equivalent | 63-8% 36-2% (26 samples) Twofold Bay Fm. equivalent | 70-0% 30-0% ( 2 samples) palaeoclimatic warming-up trend (Van Houten, — 1964) during the deposition of the Upper Devonian rocks of New South Wales. Granularmetric analyses of thin sections employing Friedman’s (1961) and Sahu’s (1964) methods support the environmental conclusions listed below under formational headings (Steiner, 1966). Provenance: The feldspar content (Figure 5, column 10) varies between 2 per cent and 17 per cent, but is generally low in the Wolumla Conglomerate Member and the Worange Point Formation. | Maximal feldspar content was recorded in the undifferentiated Twofold Bay. Formation and in the lower Bellbird Creek Formation where the feldspar is fairly fresh. The feldspar appears cloudy and weathered in the upper Bellbird Creek and Worange Point Formations. Much of this feldspar is probably of granitc origin since the feldspar point counts mimic that of granite fragments (Figure 5, compare columns 10 and 14). The point-count — — = a seesamwee hy! THE MERRIMBULA GROUP OF THE EDEN-MERRIMBULA AREA, N.S.W. 47 data of other rock fragments (rhyolite, Figure 5, column 13; other volcanic rock, column 16; metamorphic rocks, column 15; and sedi- mentary rocks, column 18) permit the following provenance conclusions : The source of the Wolumla Conglomerate near Eden was a rhyolitic volcanic terrain (i.e. Eden Rhyolite). The source of the undifferentiated Twofold Bay and lower Bellbird Creek Formations was a granitic terrain (i.e. Bega granite), and some low-grade metamorphic rocks (ie. Mallacoota Beds). The source of the upper Bellbird Creek and Worange Point Formation was a general terrain consisting of metamorphic rocks, granite, volcanic rocks, and sedimentary rock (i.e. Mallacoota Beds, Bega granite, Eden Rhyolite, possibly Lochiel basalts, sedimentary rocks, intraformational Merrimbula Group detritus). Twofold Bay Formation Wolumla Conglomerate Member, although not always present (Figure 1), consists of massive boulder to pebble purple and red conglomerate and varies in thickness from 1-5 m to 15 m. The well-rounded phenoclast consist of rhyolite, quartz porphyry, granite, sandstone, quartzite, quartz and fine-grained metamorphic rocks. The composition of the phenoclasts is strongly dependent on the lithology of the underlying rocks. Near Eden and at Edrom the pheno- clasts are rhyolite pebbles (Figure 5) which tend to be angular and subangular. The coarse- grained units particularly are characterized by high lenticularity and lateral stratigraphic discontinuity. The Wolumla conglomerate member grades transitionally into the overlying undifferentiated strata of the Twofold Bay Formation. The Wolumla conglomerate may be termed a fanglomerate (Dunbar and Rodgers, 1957) and thus represents the deposits of the upper part of an alluvial fan which sloped downward toward the north as indicated by the strong northerly cross-stratification mode (Figure _5). This fan appears to be a continuation of the underlying Lochiel alluvial fan (Steiner, 1972) which was accompanied by basic extrusions. Undifferentiated Twofold Bay Formation : The red bed sequence of the total Twofold Bay Formation varies in thickness between 70 m near Eden and 180 m in the western part of the map area at Wolumla Peak. The thickness varia- tions can be interpreted as reflecting Eden Rhyolite relief at the time of deposition. Many of the 50-60 units measured are lenticular on the outcrop scale to such an extent that the recorded units represent only one possible vertical profile. Sorting is very poor and the brick red, sandy and silty mudstone units of 1 m to 4 m thickness lack internal stratification. Scour structures, channel-type units, washouts, subaerial desiccation structures, and less common ripple marks have been observed. Isolated shale clasts and nests of shale clasts and some lenses and wedges of shale-clast conglomerates are present throughout the whole sequence. Cross-stratification is common with a strong northerly mode which swings to the north- northeast in the upper part of the Formation (Figures 5 and 6). Only fragmentary plant fossils have been recovered from the formation. In a vertical profile the units are arranged in fluvial fining-upwards cycles (Allen, 1965). These cycles are less well defined in the Twofold Bay Formation than in the Worange Point Formation or the Old Red Sandstone of Great Britain (Allen, 1962). Particularly in the Wolumla Conglomerate Member and in the lower Twofold Bay Formation the upper fine- grained sub-units of the cycles are missing. The fluvial fining-upward cycles vary in thick- ness from 1 m or less to 4 m mainly in the upper part of the Twofold Bay Formation. Incom- plete coarse-grained fluvial cycles indicate deposition by a braided stream regime (Douglas, 1962 ; Shelton and Noble, 1974). It is concluded that the Twofold Bay Forma- tion probably records the deposits of a northerly to north-northeasterly sloping alluvial fan which was built up by the deposits of a small braided stream system which transitionally grade into meandering stream deposits toward the top of the formation. Structureless, brick-red mud- stone units are interpreted as occasional mudflow deposits. In general moderately arid to semi- arid climate is favourable for the development of alluvial fans (Blissenbach, 1954). Bellbird Creek Formation The lower Bellbird Creek Formation includes numerous white granular conglomerate (grit) with less than 5 per cent small pebbles, brown or grey sandstone, and green and brown sandy shale. The overall sorting is considerably better than in the rest of the Merrimbula Group. Individual laminae of the grits are very well sorted and are often truncated at the top by an erosional surface. The grits are usually bimodal, with a major mode in the 2-4 mm size range. Such size modes are generally thought to be very uncommon in sediments around the world (Pettijohn, 1957). Sets of planar cross- stratification of less than 0-3 m thickness are common, but large-scale planar and simple 48 cross-stratification are also present. Current direction is characterized by three modes (Figures 5 and 6) which are 90° and 180° apart. Following Tanner (1955, 1959) these modes have been interpreted as shore-line trend and palaeo- slope direction, as discussed above. Small- scale scour structures and sand pockets are interpreted as back shore features (McKee, 1957 ; Soliman, 1964). Shale clasts are present throughout. Organically disturbed or burrowed laminae are not as common as in the upper Bellbird Creek Formation but broken, curled and bent laminae are fairly common and are interpreted as desiccation structures. Many of the disturbed horizons are due to slumping and load casting. The Lower Bellbird Creek Formation contains some graded bedding and reversed graded bedding in the form of coarsening-upward cycles of various magnitude. Coarsening-upward units are typical of barrier island deposits (Straaten, 1961). Sedimentation units are much more laterally continuous than in the Twofold Bay Formation and some thicker sequences (3 to 25 m) can be correlated over a distance of up to 5 km indicating sheet- like sedimentation units. The total Bellbird Creek Formation has yielded a marine fauna. The basal 75 m of the lower Bellbird Creek Formation record the deposits of a marine transgression in which barrier island, littoral and shallow marine facies have been identified. The overlying 160 m record the deposits of a subaqueous deltaic phase including some littoral and lagoonal or shallow marine deposits. The Upper Bellbird Creek Formation character- istically consists of medium-grained sandstone and laminated finer sedimentary rocks. The maximum grain size is only slightly larger than the mean grain-size, indicating good sorting. Unstratified, red mudstone units which are typical of the Twofold Bay and Worange Point Formation are not present in the entire Bellbird Creek sequence. In the upper Bellbird Creek Formation units of alternating brown sandy and green, muddy laminae are typical whereby groups of laminae are often lenticular. The types of cross-stratifications are similar to those in the lower Bellbird Creek Formation. Ripple marks of all types are particularly common and are also present in reddish well-laminated shale. Interference ripples and rippled troughs have also been observed. Shale clasts are also common. Ball and pillow structures which have been attributed to quicksand conditions (Shelley, 1964; Shearman, 1964) have been observed. Units of burrowed and disturbed J. STEINER laminations are common in specific regular — intervals. Broken and curled laminae indicative of desiccation also occur in regular intervals. — Rain prints (Hall, personal communication) have — been reported and also argue in favour of at least — Slumping and — Sedimentation units © temporary subaerial exposure. load casting are present. are of constant thickness and are laterally continuous facilitating correlation similar to the lower Bellbird Creek Formation. vertical profile many of the sedimentation units are grouped into eight tidal flat fining-upward cycles (Klein, 1971). while in the upper, finer-grained units the ripple mark trends tend to parallel the shoreline. The tidal flat fining-upward sequences range from 3 m to 9m and average 4:6 m. Granular- metric analysis identified some dune deposits | (Steiner, 1966). The basal 85 m of the upper Bellbird Creek F Formation consists of deltaic tidal flat deposits with an average tidal range of 4-6 m neglecting compaction. The upper 25 m are interpreted | as transitional facies of lagoon, marsh and | In a ¥ The coarser lower units — of these cycles commonly have ripple mark © trends perpendicular to the ancient shore-line | coastal stream deposits associated with a few wind-blown units at the top. The Worange Point Formation The thickness of the formation is 420 m plus because the top of it is undefined. The forma- tion which has yielded no macrofossils constitutes the upper major red-bed sequence of the © Merrimbula Group and due to the presence of well developed fluvial fining-upward cycles it | resembles many red-bed sequences around the — world (Allen, 1965). The basal 100 m lack conglomerates and are also devoid of sandy red © mudstone units in excess of 3 m. Bay Formation. Intraformational con- glomerate consisting of shale-clast are common and vary in thickness from 15 cm to 2m. The © conglomerate phenoclasts are subrounded to © where | measured is roughly perpendicular to current © well-rounded. Pebble elongation direction. Pebble imbrication with the long axes dipping up-current is present. above. throughout the section but the standard devia- — tion of the azimuthal mode is large (18°, see | Table 5) indicating higher variability of palaeo- © current direction than in the Twofold Bay Oversteepened and slumped cross- Formation. In general © such units are less common than in the Twofold ~ Con- | glomeritic sandstones are common and are | included in the sandstone statistics discussed © Planar cross-stratification is present | THE MERRIMBULA GROUP OF THE EDEN-MERRIMBULA AREA, N.S.W. stratification is common. Ball and _ pillow j, | Structures are associated with specific sub-units of fining-upward cycles. Units with parallel laminations and small scale cross-stratification nm occur at specific intervals. Trough-like cross- ''} stratification on the scale of a few feet laterally i is much less common than in the Twofold Bay ‘] Formation. Load casts and other irregularities at the base of coarser units overlying red mudstone are present. Well developed, in-filled lls} mud cracks are also present. Graded bedding, ut particularly of maximum grain size, is very i common and so are channels, scour structures, e shale clasts, and nests of shale clasts. Twelve it# channel thicknesses (or channel depths) vary M4 from 2-1 to 7-5 m and average 3:7 m. Sedi- mentation units are laterally much more Is continuous than in the Twofold Bay Formation, although lensing and wedging has been observed. In correlating the various sections considerable lensing of major units on a scale of 400 m have ei been noted. The Worange Point Formation sls§ measured consists of 16 well-developed fluvial tig fining-upward. cycles plus less frequent finer- def grained flood deposits which are associated with ai non-cyclic sandstone units. The cycles, exclud- A preliminary palynological examination of a few samples of the Upper Bellbird Creek Formation and Worange Point Formation of the Merrimbula Group has been carried out. Neves’ and Dale’s (1963) method of separation has been employed. The Upper Bellbird Creek Formation is characterized by a rich association of acritarchs, miospores and rare poorly preserved chitinozoans B(ancyrochitinids) particularly in Sample JS4 224. The microfossil assemblage reflects a distinct marine phase. A detailed analysis of the acritarchs shows the following species : Ammonidium spp. Ouvernay sphaera radiata Brito Evittia remota (Deunff) Lister Estiastria spp. Leiofusa sp. Brito 49 ing the flood deposits, range in thickness from 8-3 m to 28 mand average 15m. Locally these cycles are overlain by mudstones ranging in thickness from 6 to 12 m and average 8-3 m. The Worange Point Formation records the deposits of a wide meandering river belt situated on a coastal plain with a palaeoslope dipping gently toward the southeast. The basal 100 m of the formation probably represent subaerial top-set deltaic beds. In using the thickness of the fining-upward sub-cycles and the Brazos River, Texas (Bernard and Major, 1963) for comparison the dimensions of the Worange Point river system may have been as follows : Width of meander belt 2-6 km Normal low water stage 4m Normal high water stage 9-3 m Average flood stage .. 13-3 m Maximum flood stage 17m Acknowledgements The author is indebted to K. A. W. Crook for guidance and for suggesting this study which was made possible by an Australian National University Research Scholarship. the Appendix A Preliminary Report on the Palynology of the Merrimbula Group, N.S.W. R. ANAN-YORKE Maranhites brasiliensis Form A_ (Brito) Daemon et al. Maranhites brasiliensis Form P (Brito) Daemon ¢é¢ al. Multiplicisphaeridium ramusculosum (De- flandre) Lister Multiplicisphaeridium arbusculiferum (Downie) Staplin Nae eisenacki (Brito and Santos) Combaz et al. Navifusa brasiliensis Combaz et al. Pterospermopsis sp. Stellintum octoaster (Staplin) Jardiné et al. Tumsphaeridium caudatum Deunff and Evitt Triangulina alargada Cramer Viliferites tenuimarginatus Brito (Brito and Santos) 50 J. STEINER Veryhachium europaeum (Stockmans and Williére) Cramer Veryhachium lairdi (Deflandre) Deunff Veryhachium trispinosum (Eisenack) Cramer Veryhachium stelligerum Deunff Cymatisphaera spp. The spore assemblage is varied, consisting of Ancyrospora, Apiculatisporis, Apiculiretusispora, Convulatispora, Contagisporites, Emphanisporites, Hymenozonotriletes, Spinozonotriletes, Reticula- tisporites, Retusotriletes, Geminospora, V errucost- sporites and others. The occurrence of ancyrochitinids delimits the age of the microfossil assemblage to the pre-Carboniferous age. Several of the acritarchs have been recorded from Lower-Upper Devonian sediments in various localities in Europe, North America, South America and Africa. The varied spore assemblage is consistent with an Upper Devonian age. Characteristic Fammenian elements such as Hymenozonotriletes lepidophytus Kedo were not observed. Several samples processed from the Worange Point Formation were barren. Samples JS4 570-572, JS8 511-516 and JS8 521/TS 199 consist of significant palynofloras, though diagnostic forms were not observed. The architarchs are very rare in the Worange Point Formation. Only a few specimens of the species listed below were observed. Ammontdium sp. Cymatiosphaera spp. Evittia remota (Deunff) Lister Estiastra sp. Maranhites brasiliensis Form A _ (Brito) Daemon eé¢ al. Multiplicisphaeridium vamusculosum (De- flandre) Lister Multiplicisphaeridium arbusculiferum (Downie) Staplin Navifusa eisenackt (Brito and Santos) Combaz et al. Stellinium octoaster (Staplin) Jardiné e¢ al. Triangulina alargada Cramer Veryhachium rabiosum Cramer restricted Veryhachium europaeum (Stockmans Williére) Cramer Veryhachium trispinosum (Eisenack) Cramer and The spores are rare in the samples though are more varied and constitute a higher percentage than the acritarchs. The spore assemblage in Sample JS8/511-516 is quite significant. Emphanisporites, Retusotriletes, Apiculatispors, Apiculiretusispora, Hymenozonotriletes, Spinozo- notriletes, Raistrickia, Granulatisporites, Convul- atispora occur fairly commonly. The playno- floral assemblage is distinctively of Devonian age. The palynofloral assemblage is too poor to suggest a more specific age assignment but the total assemblage suggests very minor marine ~ interbeds_ stratigraphically high up in the Worange Point Formation. References ALLEN, J. R. L., 1962. tion of the Highest Lower Old Red Sandstone of 657. ALLEN, J. R. L., 1965. Alluvial Successions. Geol. Journ., 4, 229. BERNARD, H. A., and Major, C. F., 1963. Recent Meander Belt Deposits of the Brazos River: an Petrol. | Alluvial ‘‘ Sand” Geol. Bull., 47, 350. Model. Amer. Ass. BLISSENBACH, E., 1954. Geology of Alluvial Fans in | Semi-Arid Regions. Bull. Geol. Soc. Amer., 65, 175. Bouma, A. H., 1962. Sedimentology of Some Flysch Deposits, a Gvaphic Approach to Facies Inter- pretations. Elsevier Publ. Co., Amsterdam. Brown, I. A., 1931. The Stratigraphy and Structural Geology of the Devonian Rocks of the South Coast of New South Wales. Proc. Linn. Soc. N.S.W., 56, 461. ConoLtty, J. R., 1965. Clay Mineralogy of Some Upper Devonian Sediments from Central New South Wales. J. Proc. Roy. Soc. N.S.W., 98, 111. Crook, K. A. W., 1960. Classification of Arenites. Amer. Journ. Science, 258, 419. Crook, K. A. W., 1967. Upper Devonian Sedimento- logical Provinces in Eastern Australia and their Controlling Factors, in Oswald, D. H. (Ed), International Symposium on the Devonian System. Alberta Soc. Petrol. Geol., 1335. Doectas, D. J., 1962. The Structure of Sedimentary Deposits of Braided Rivers. Sedimentology, 1, 167. DunBar, C. O., and RopcErs, J., 1957. Stratigraphy. Wiley, New York. FRIEDMAN, G. M., 1961. Distinction Between Dune, Beach and River Sands from their Textural Characteristics. J. Sed. Pet., 31, 514. GEOLOGICAL SOCIETY OF AMERICA, 1951. Chart. Boulder, Colorado. Hat, L. R., 1957. The Stratigraphy, Structure and Mineralization of the Devonian Strata near Eden, N.S.W. Rept. Dept. Mines, N.S.W., 5, 103. Principles of Hatt, L. R., 1969. Quaama-Eden-Cape Howe District |} in Packam et al., in Packham, G. H. (Ed.), The Geology of New South Wales. J. Geol. Soc. Aust., 16, 156. § Hi, D., 1969. Devonian of Eastern Australia, im Oswald, D. H. (Ed.), International Symposium on the Devonian System. Alberta Soc. Petrol. Geol., 613. KLEIN, G. DEV., 1971. A Sedimentary Model for Determining Paleotidal Range. Bull., 82, 2585. McKeEE, E. D., 1957. Recent Sediments. Bull. Amer. Ass. Petrol. Geol., § 41, 1704. a McKeEE, E. D., and WErr, W., 1953. Terminology for © Stratification and Cross-Stratification in Sediment- | ary Rocks. Bull. Geol. Soc. Amer., 64, 383. Petrology, Origin and Deposi- Shropshire, England. J. Sediment. Petrol., 32, Fining-upward Cycles in — Rock Colour ‘ Geol. Soc. Amer. | Primary Structures in Some | THE MERRIMBULA GROUP OF THE EDEN-MERRIMBULA AREA, N.S.W. 51 Nairn, A. E. H. (Ed.), Problems in Palaeoclimatology. Interscience Publ., New York. NEVES, R., and Date, B., 1963. A Modified Filtration System for Palynological Preparations. Nature, 198, 775. PETTIJOHN, F. J., 1949. Sedimentary Rocks, 2nd ed. r and Bros., New York. Sanu, B. K., 1964. Depositional Mechanism from the Size Analysis of Clastic Sediments. Journ. Sed. Pet., 34, 73. SHEARMAN, D. J., 1964. On Penecontemporaneous Disturbance of Bedding by ‘Quick Sand” Movement in the Devonian Rocks of North Devon. Deltaic and Shallow Marine Deposits. Elsevier, London. SHELLEY, R. C., 1964. On Penecontemporaneous Deformation of Heavy Mineral Bands in the Torridonian Sandstone of Northwest Scotland. Deltaic and Shallow Marine Deposits. Elsevier, London. SHELTON, J. W., and NoBLz, R. L., 1974. Depositional Features of Braided-Meandering Stream. Amer. Ass. Petrol. Geol. Bull., 58, 742. Australian National University, Canberra, A.C.T. 2600. Australia. Present Address : Department of Geology, University of Alberta, Edmonton, Alberta, Canada. Soitmman, S. M., 1964. Primary Structures in a Part of the Nile Delta Sand Beach. Deltaic and Shallow Marine Deposits. Elsevier, London. STEINER, J., 1966. Depositional Environments of the Devonian Rocks of the Eden-Merrimbula Area, N.S.W., Ph.D. Thesis, Australian National Uni- versity (unpublished). STEINER, J., 1972. The Eruptive History and Deposi- tional Environment of the Devonian Extrusive Rocks, Eden, N.S.W. J. Geol. Soc. Aust., 19, 261. STRAATEN, V. L. M. J. V., 1961. Tidal Flat Areas. 9, 203. TANNER, W. F., 1955. Paleogeographic Reconstruc- tion from Cross-bedding Studies. Bull. Amer. Ass. Petrol. Geol., 39, 2471. TANNER, W. F., 1959. The Importance of Modes in Cross-bedding Data. J. Sed. Petrol., 29, 221. Van Houten, F. B., 1964. Origin of Red Beds— Some Unsolved Problems (see Nairn). Sedimentation in J. Alberta Soc. Petrol. Geol., (Received 23.9.74) Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 52-53, 1975 Local Compactness and Free Products of Topological Groups SipNEY A. Morris ABSTRACT—It is proved here that a free product (free abelian product) of an infinite family of non-totally disconnected topological groups is never locally compact. 1, Introduction Let {G;:ieI} be a family of topological groups. Then the topological group F is said to be a free product of {G; : ie}, denoted by II*G;, if it has the properties : t€. (a) for each tel, G; is a subgroup of F; (b) F is generated algebraically by UG; ; tel Definition. (c) if for each teJ, y;, is a continuous homo- morphism of G; into a topological group H, then there exists a continuous homo- morphism [° of F into H such that [=y; on Gj, for each 7. Of course a free product is simply the coproduct in the category of all topological groups. Thus, if it exists, it is unique up to (a unique) isomorphism. The free abelian product is similarly defined and is the coproduct in the category of all abelian topological groups. Free products of topological groups were first studied by Graev (1950). He showed that the free product of any family of Hausdorff groups exists and is Hausdorff. (A much simpler—but fallacious—proof of this result appears in Morris (1971). A simple proof of a special case is given in Ordman (1974). We summarize the other background results in the following Theorem. Let {G;:teI} be a family of (not necessarily Hausdorff) topological groups. (i) Morris (1971). II*G; exists and has as tel its underlying group structure the free algebraic product of G,, tel. (ii) Hulanicki (1967) and Morris (1971). If each G, is maximally periodic, then I od OF is maximally almost periodic. a (iii) Morris (1971). If each G; is connected, then II*G; is connected. tel (iv) Ordman (1974). If TI"G; is Hausdorff, then each G; is a Hee subgroup. (v) Ordman (1974). If at least two G; are not {e}, then TSG, is not compact. (vi) Ordman 1974), If at least two G; are not discrete, then lise; is not both locally compact and ince invariant. Note that in our main theorem and in part (vi) of the above theorem a non- triviality condition is assumed. Some such condition is necessary, as the free product of discrete groups is discrete. 2. Results Lemma. Let {G;:teI} be an infinite family of non-totally disconnected locally compact groups. Let G be the algebraic restricted direct product of {G;:zeZ} with the finest group topology which will induce the given topology on each G;. Then G is not locally compact. Proof. Suppose G is locally compact. Let C; be the component of the identity in G;, for each tel. Case 1. There exists an infinite subset J of I such that for each je J, Cj; has a subgroup Rj; isomorphic to the additive group of reals with its usual topology. Of course each Rj has a subgroup Z, isomorphic to the discrete group of integers. Let 1G: denote the restricted direct product of {G,: Tuer }, with the usual topology. Then there is a natural continuous algebraic iso- morphism f of G onto TPG, such that f|G,; is an isomorphism of G; into J(G,), for each tel. ‘Let A be the suberote of G generated algebraically by > Rj. Since Rj is ion compact, f(Rj) is a olase subgroup of /(G;) = are LOCAL COMPACTNESS AND FREE PRODUCTS OF TOPOLOGICAL GROUPS 53 Thus /(A)=ILf(R,) is a closed subgroup of ar 11?G,. Therefore, A is a closed subgroup of G t€. and consequently is locally compact. Similarly if we define B to be the subgroup of G generated algebraically by U Z;, then B is J locally compact. Since B is algebraically iso- morphic to [I2Z;, this implies by Dudley je (1961), that B ot the discrete topology. Since each Rj, jeJ, is connected, A is connected. Thus A is a compactly generated locally compact abelian group which has B as a discrete subgroup. By Corollary 1 of Morris (1972), B is finitely generated. This contradicts the definition of B. Thus Case 1 cannot occur. Case 2. There exists an infinite subset K of J, such that each C, is compact, keK. Let C be the subgroup of G generated algebraically by UC,. Since C, is compact, keK f(C,) is a closed subgroup of f(G,)=G,. Thus f(C)= Tip J(C,) is a closed subgroup of II2G;,. iel €. € Therefore C is a closed subgroup of G and consequently is locally compact. Clearly C is also connected. By §4.13 of Montgomery and Zippin (1955), C has a maximal compact subgroup M. Since C, is a normal subgroup of C, MC, is a subgroup of C,foreachkeK. Noting that MC, is compact and contains M, we see that MC,=M. Thus C, is a subgroup of M, for each keK. The family {C, : keK} generates C algebraically and so M=C ; that is, C is compact. However, if C is compact then f(C)= TPAC x) is compact. This contradicts Theorem e 6.2 of Hewitt and Ross (1963) which clearly implies a restricted direct product of an infinite family of non-trivial groups is never compact. This contradiction shows that Case 2 cannot occur. Now, by §4.13 of Montgomery and Zippin (1955) and our assumptions on the family {G,:teI}, if G is locally compact then either Case 1 or Case 2 must occur. Hence G is not locally compact. Department of Mathematics, University of New South Wales, Kensington, N.S.W., 2033, Australia. Theorem. Let {G;: te} be an infinite family of non-totally disconnected topological groups. Then II*G; is not locally compact. tel Proof. Suppose II*G,; is locally compact. tel Then by part (iv) of our preliminary theorem, each G; is locally compact. Let G be defined asintheLemma. Then clearly there is a natural continuous open homomorphism of II*G; onto tel G. Thus G is locally compact. This contra- dicts the Lemma. Hence II*G; is not locally tel compact. Similarly we obtain the following : Theorem. Let {G;:teI} be an infinite family of abelian non-totally disconnected topological groups. Then the free abelian products of {G;:ieI} is not locally compact. We conclude by drawing the reader’s attention to some work which complements the results obtained here: Morris, Ordman and Thompson (1973) and Morris (1975). References Dub Ley, R. M., 1961. Continuity of Homomorphisms. Duke Math. J., 28, 587. GraEv, M. I., 1950. On Free Products of Topological Groups (Russian). Jzv. Akad. Nauk SSSR. Ser. Mat., 14, 343. Hewitt, E., and Ross, K. A., 1963. Abstract Havmonic Analysis, Vol. I. Springer-Verlag, Berlin, G6éttingen, Heidelberg. Hutanicki, A., 1967. Isomorphic Embeddings of Free Products of Compact Groups. Collog. Math., 16, 235. MontGoMErY, D., and Zippin, L., 1955. Topological Transformation Groups. Interscience, New York. Morris, S. A., 1971. Free Products of Topological Groups. Bull. Austral. Math. Soc., 4, 17. Morris, S.A., 1972. Locally Compact Abelian Groups and the Variety of Topological Groups Generated by the Reals. Proc. Amer. Math. Soc., 34, 290. Morris, S.A., 1975, Local Compactness and Local Invariance of Free Products of Topological Groups. Collog. Math., Morris, S. A., ORDMAN, E. T., and THompson, H. B., 1973. The Topology of Free Products of Topo- logical Groups. Pyoc. second. International Con- ference on Group Theory (Canberra), 1973. OrpMaN, E. T., 1974. Free Products of Topological Groups with Equal Uniformities. Collog. Math. (Received 29.4.74) Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 54-69, 1975 Lower Silurian Rugose Corals from Central New South Wales R. A. McLEAN ABSTRACT—Six species of rugose corals (four new) are described from beds of Upper Llandovery ageincentralN.S.W. Representative of the family Arachnophyllidae Dybowski are Avachnophyllum epistomoides Etheridge, 1909 (Rosyth and Quarry Creek Limestones), Ptychophyllum auctum sp. nov. (Rosyth and Quarry Creek Limestones), P. cf. sibivicum Ivanovskiy, 1963 (Upper limestone horizon, Cobblers Creek, Angullong district), Stereoxylodes multicarinatus sp. nov. (Rosyth Limestone). Limestone) has uncertain suprageneric affinities. Introduction The rugosans described herein are represented in three major horizons west of Orange in central N.S.W. A summary of the stratigraphy of the correlative Rosyth and Quarry Creek Lime- stones, together with evidence for their Upper Llandovery age, are given in McLean (1974a). Similar data for the Upper Llandovery “ upper limestone horizon ”’ in Cobblers Creek, Angullong district, is provided by McLean (19740). This paper presents the first description of representatives from Australia of the genera Ptychophyllum Edwards and Haime, Cyathactis Soshkina, Stereoxylodes Wang and Strombodes Schweigger. In addition, a widely neglected species of Avachnophyllum Dana is revised and a lectotype chosen. Specimen numbers in the University of Sydney Palaeontological Collections bear the prefix SUP and where more than one section has been prepared from the one specimen, they have the suffix a, b etc. Numbers of specimens in the palaeontological collections of the Australian Museum, Sydney, have the prefix AM.F and thin sections in these collections the prefix AM. Full details of collecting localities within the Rosyth Limestone of the Boree Creek area, south of the Orange-Cudal road are given in McLean (1973). Systematic Palaeontology Family Arachnophyllidae Dybowski, 1873 Genus Avachnophyllum Dana, 1846 1876 Strombodes; Rominger, p. 130. 1901 Avachnophyllum; Lambe, p. 180. 1902 Strombodes; Poéta, p. 176. 1906 Avachnophyllum (Strombodes); Foerste, p- 318. 1909 22-5 74 45204c_ .. = 23 74 45204d_ .. Sc > 22 62 45205a (calice) .. Si b 60 45205b .. >18 60 45205c >15 258 45205d >15 56 45205e >15 ?31 45206a (calice) .. >16-5 32* 45206b_.. oe 18:5 34* 45206c_ .. Be 18 34* 45206d_ .. ae 18 33* 45206e .. td 214 33* 45206f ?10 ?25* 45207 aad ae 23 60 45208a (calice) .. >29 72 45208b_ .. 33 70 “strands” that appear contiguous with dis- sepiments adjacent to septa (see discussion above). Septa in this zone may reach a diameter of about 0-7 mm. In tabularium, major septa become thinner, most continuing to axis to form prominent axial vortex and septa in this region have common width of approx- imately 0-15 mm. Minor septa short, although total length cannot be determined owing to incomplete preservation of corallites. However, none reach axially as far as dissepimentarial- tabularial boundary. Where minor septa can — be observed in sections they are thin and in the © specimen from the Rosyth Limestone (SUP 45208), their discontinuous nature can be seen © (Plate II, Figures 8, 10). Dissepiments very steeply inclined and elongate adjacent to © tabularium. Towards periphery, dissepiments — slightly less inclined and more globose; generally they are small in size (av. 1-1-5 mm in width, 0-5-0-6 mm in height, although the Rosyth Limestone specimen is slightly larger). Tabularium composed of moderately arched series of mainly elongate tabellae, which tend © to be more globose towards margin of dis- sepimentarium. Average height of tabellae reaches 0-5-0-8 mm. Remarks : The only species of Ptychophyllum to show any strong similarities to P. auctum sp. nov. is P. sibiricum Ivanovskiy, 19636, from the Upper Llandovery of the Siberian Platform. Comparable features include the predominantly cylindricum growth form, corallite diameter | (20-30 mm), broad axial vortex of major septa, © steeply inclined rows of small, slightly elongate dissepiments and the size, shape and disposition of the tabellae. P. dilation of the major septa in the dissepiment- arium and comparable widths of the major and minor septa in this region. minor septa, tabularium (approx. 15 mm at corallite diameter 21 mm, compared to 13 mm at an approximate diameter of 25 mm in P. auctum). Ivanovskiy (1963), p. 79) (Plate XXI, Figure la) made no mention of peripheral breakdown — of septa in his description of P. stbiricum and there is none evident in his illustration although the specimen may be incomplete (epitheca not — It is evident, however, that the two visible). sibiricum may be dis- © tinguished, however, by having much weaker — It also has longer — reaching apparently to the tabularial boundary and a proportionately wider © species are related closely, owing to the dilation } of septa in the dissepimentarium and their thinning into a broad axial vortex. The specimen (SUP 45208) from the Rosyth Limestone is included in P. Creek Limestone material and appears to generally have longer minor septa, slightly more globose dissepiments and, in the more distal transverse section (Plate II, Figure 10), the septa appear far more discontinuous peripherally © than is normally shown in the Quarry Creek | in the more proximal ~ material. However, transverse section (Plate II, Figure 8), the septa | auctum with — reservation,’ since it is larger than the Quarry B23 BSH a - cel Cree pxintal sep LOWER SILURIAN RUGOSE CORALS FROM CENTRAL NEW SOUTH WALES 59 are more similar to the typical P. auctum. The strong dilation of the major septa in the dis- sepimentarium links this form to the repre- sentatives of the species from Quarry Creek and until more material from the Rosyth Limestone can be located, it appears best included as P. auctum?. Ptychophyllum cf. sibiricum Ivanovskiy, 1963 Plate III, Figures 3-9 Material: SUP 20111, 45209-45215. Upper limestone horizon, Cobblers Creek, Angullong district. Upper Llandovery. Diagnosis: Cylindrical Ptychophyllum with corallite diameter up to 19 mm. Septa range in number from 48 to 66, major septa forming axial vortex of variable intensity. Both major and minor septa thickened in dissepimentarium. Dissepiments small, moderately elongate, steeply inclined ; tabellae elongate and in arched series. Description : Probably cylindrical coralla with corallite diameter ranging from 10 to 13-5 mm in material available although corallites are abraded as in P. auctum sp. nov. Calice moderately deep (depth at least 8 mm in SUP 45214) with steep walls and convex-upward base. TABLE 2 Dimensions of Ptychophyllum ef. sibiricum Ivanovskiy Slide No. (SUP) | Dc (mm) n 20111a ri sl 16 62 45209a_ ls. ta 18 58 45210... a 15 Sing sare 45211 Ps He ane ae 58 45212a (calice) .. 18-5 56 45212b_ .. ad 19 56 j 45212c_ .. lt 17°5 56 45213a .. as Pa agepts 62 4521l5a 5 § Septal number ranges from 48 in smallest " @specimen to 66, with an average of 56 to 58. ‘BSeptal number and corallite diameters for ‘specimens available are listed in Table 2. Both major and minor septa are dilated in dis- sepimentarium, the major septa being slightly wider than the minor septa. Major septa taper axially, forming a generally prominent axial vortex (e.g. SUP 45210, 45212, Plate III, Figure 8). Owing to the incomplete nature of the material, however, this variation in axial vortex could be due to sections cut at different onto- genetic stages—there was material available for only one transverse and longitudinal section in most cases. It is notable, however, that in one specimen, SUP 45212, there is quite a variation in the intensity of the axial vortex, although it is uncertain at what position in the corallite the original sections were made. Minor septa are long, extending axially to margin of tabularium. Preservation insufficient to confirm any peripheral breakdown of septa. Dissepiments small, weakly elongate and steeply inclined, average height 0:4 mm, width 0:8 mm. Tabularium composed of moderately arched series of elongate tabellae, usually somewhat flattened marginally but becoming more domed in arched axial region. Average height of tabellae 0-8-1 mm. Diameter of tabularium commonly 8-10 mm, i.e. slightly more than half diameter of corallite. Remarks : The above described material bears closest resemblance to the Upper Llandovery species Ptychophyllum sibiricum Ivanovskiy, 1963, from the Siberian Platform. Similarities may be seen in the septa being thickened in the dissepimentarium and tapering axially in a broad axial vortex, together with the minor septa extending axially as far as the tabularium and being thickened almost equally with the major septa in the dissepimentarium. Also the dissepiments are of comparable size, shape, and inclination to the axis and the tabellae are of similar size and disposition. The Siberian material differs somewhat in being generally larger (corallite diameter commonly 21-22 m, max. 32 mm, compared to a maximum of 19 mm observed in the Angullong specimens). They also show a proportionally larger number of septa (92, n/Dc=4-38 as compared to generally 56 to 58, n/Dc 3-2-4-0). However, the close relationship to P. sibiricum is evident in all other features. P. cf. sibiricum may be distinguished from P. auctum sp. nov., by having much less pronounced thinning of the major septa in the tabularium as well as minor septa extending axially to the tabularium and thickened almost equally with the major septa in the dissepiment- arium. No evidence of peripheral breakdown of the septa in P. cf. sibivicum can be confirmed, although the state of preservaticn is poorer than in the material of P. auctum from the Quarry Creek Limestone. 60 R. A. McLEAN Genus Cyathactis Soshkina, 1955 1901 Cyathophyllum (part.) ; Lambe, p. 133. 1928 Cyathophyllum (part.); | Twenhofel, pally 1939 Cyathophyllum (part.); Northrop, p. 141. 1955 Cyathactis (part.) Soshkina, p. 122. -1963b Cyathactis (? part.) ; Ivanovskiy, p. 75 (cum syn.). 1965a Cyathactis ; Ivanovskiy, p. 76. 1965c Cyathactis; Ivanovskiy, p. 25. 1971 Cyathactis; Lavrusevich, p. 62. 1972 Cyathactis; Merriam, p. 33. Type species: C. typus Soshkina, 1955 ; Upper Llandovery, Siberian Platform. Diagnosis: Solitary corallum with generally straight, thin septa of two orders, the major septa usually reaching or nearly reaching the axis. Dissepiments numerous, mainly globose ; tabularlum composed of complete and incomplete tabulae, with or without tabellae. Discussion: The genus showing greatest resemblances to Cyathactis is Ptychophyllum Edwards and Haime, as discussed by Ivanovskiy (1965c). The features that distinguish it from Cyathactis are its development of an axial vortex of the major septa, together with the presence of numerous tabellae. The following species are regarded herein as probable representatives of the genus Cyathactis : C. typus Soshkina, 1955; C. tenuiseptatus Soshkina, 1955; C. balticus Kaljo, 1958; C. longiseptatus Lavrusevich, 1971; C. gazellensis Merriam, 1972 ; C. curyone (Billings, 1862); C. anticostiense (Billings, 1862) ; interruptus (Billings, 1862) and C. cormorantense (Twenhofel, 1928). Range : Lower Llandovery of Estonia; Middle Llandovery of Tadzhikistan; Middle—Upper Llandovery of Siberian Platform and Anticosti Island ; Upper Llandovery of Estonia, ? Urals, ? south-west Siberia, north-east U.S.S.R., Quebec (Gaspé) and N.S.W.; Wenlock of Siberian Platform, Tadzhikistan, Anticosti Island, Quebec (Gaspé) and ? Nevada; Ludlow of Quebec (Gaspé) and ? California. Cyathactis variabilis sp. nov. Plate III, Figures 10-12 ; Plate IV, Figures 1, 2 Derivation of name: Latin variabilis=variable, referring to the differences in dissepimental size and shape. Material: Holotype SUP 46181. Paratypes_ SUP 46182, 46183. Rosyth Limestone, Boree Creek area. Upper Llandovery. Diagnosis: Cyathactis having a deep calice ; relatively few septa, somewhat thickened in the © dissepimentarium ; numerous dissepiments of © very variable size ; and arched, closely spaced, incomplete tabulae and tabellae. Description : Corallum incomplete but probably - turbinate with corallite diameter of at least | 45 mm. at base of calicular pit. Total mature — height of corallum not less than 45 mm. § Epitheca and peripheral parts of dissepiment- arium not preserved in any of available material. — Calice deep, not completely preserved in any specimens, but at least 10 mm in depth with © maximum width of approximately 25 mm at | base of calicular pit, the base being slightly | arched. . | Septa long, major septa extending to axis | where they may be weakly curved (see Plate IV, | Figure 2). Minor septa at least half length of | major septa. Total number of septa not certain | due to incomplete nature of material but | probably about 80 are present. Septa show — abruptly thinner in tabularium (see Plate III, | Figure 12). : Tabularium broad, with maximum diameter | of approximately 25 mm in largest specimen. smallest (SUP 46183). Tabulae moderately | arched, mainly complete in axial region, with | zone of elongate tabellae in peripheral area. | Tabular spacing commonly 0-3-0-6 mm.) Dissepiments small, moderately inclined to axis, | becoming steep closer to tabularium. At least | 12 rows of dissepiments present, but material | is incomplete. Dissepiments commonly small | and weakly elongate, size variable, average | 0-5-1 mm wide and 0-3-0-8 mm high, bu i often larger, elongate forms are present, ranging jj up to 3-3-5 mm wide and 1-1-5 mm high. | Remarks : Although only three very incomplete | specimens have been found, enough material is | present to build up a reasonable picture of the | form and compare it with other described species. | None of these species bear any close resemblance to C. variabilis sp. nov. in all features, but some similarities are evident. +f The only forms to show a comparable number of septa to C. variabilis are C. cormorantense (Twenhofel, 1928) and C. longiseptatus Lavrusevich, 1971. C. cormorantense appears comparable in septal number and corallite size, i+ io LOWER SILURIAN RUGOSE CORALS FROM CENTRAL NEW SOUTH WALES 61 but may be distinguished in having widely spaced, flattened tabulae and a narrower dissepimentarium. It also appears to lack septal dilation and has shorter major septa (see Twenhofel, 1928, Plate III, Figures 3-4). C. longiseptatus occurs in Horizon G to Horizon K (Middle Llandovery-Lower Wenlock) of Tadzhikistan and is similar to C. variabilis in septal number and length and tabularial size andform. However, it differs in lacking dilation of septa in the dissepimentarium, having a much smaller corallite size and smaller, more uniformly sized dissepiments (see Lavrusevich, 1971, Plate VIII, Figures 2-4). The North American forms C. anticostiense (Billings, 1862) and C. interruptus (Billings, 1862) are both large forms like C. variabilis, but have a greater number of septa (more than 100) and much narrower tabularium together with more uniformly sized dissepiments (see Lambe, 1901, Plate X, Figure 6 and Plate XI, Figure 3). In general, C. variabilis is distinguished from other described species of Cyathactis by having peripheral dilation of septa and dissepiments of variable size. Genus Stereoxylodes Wang, 1944 1894 Cyathophyllum (Heliophylium) ; Weis- sermel, p. 591. 1902 Cyathophyllum (part.); Poéta, p. 87. 1927 Xylodes (part.) Lang and Smith, p. 475. 1929 Xylodes (part.) ; Smith and Tremberth, . 362. 1939 Xylodes (part.) ; Weissermel, p. 47. 1940 1944 Xylodes (part.) : Prantl, p. 6. Entelophyllum (Stereoxylodes) Wang, p. 24. Entelophyllum (part.) ; 244. Entelophyllum (part.) ; Hill, p. F275. Ptychophyllum (Nanshanophylium) Yi, p. 612. Stereoxylodes ; 21951 Schouppé, p. 1956 21956 21960 ' 1962 1964 21964 1964 Zheltonogova, p. 77. Stereoxylodes ; Soshkina e¢ al., p. 319. Stereoxylodes ; Strelnikov, p. 57. Carinophyllum Strelnikov, p. 59. Ramulophyllum (? part.) Nikolaeva, p. 52. Ornatophyllum Nikolaeva, p. 57. Stereoxylodes ; Ivanovskiy, p. 71. Carinophyllum ; Ivanovskiy, p. 71. Ramulophyllum ; Sytova and Ulitina, 241. 21964 (19654 ?1965a C 1966 Pp. Ramuilophyllum ; Sytova, p. 62. 1968 ?1968 Carinophyllum; Shurygina, p. 129. 1970 Stereoxylodes ; Sytova, p. 70. 21971 Carinophyllum; Strelnikov, p. 78. Type species: Cyathophyllum (Heliophyllum) pseudodianthus Weissermel, 1894. Wenlock or Ludlow. Germany (drift.) Diagnosis: Phaceloid or solitary corallum with septa typically dilated peripherally and strongly carinate. Dissepiments numerous and tabulae commonly show differentiation into axial and periaxial series. Discussion: Stereoxylodes was _ originally described as a subgenus of Entelophyllum Wedekind, 1927 by Wang (1944) and was erected to include those forms previously included in Entelophyllum but which possess _ strongly carinate, peripherally dilated septa. Hill (1956) listed Stereoxylodes as a synonym of Entelo- phyllum but subsequent authors have considered it as a full genus, this seeming reasonable on the basis of Stereoxylodes having typically strongly carinate and dilated septa. However, their views on the nature and interpretation of the genus have varied. Zheltonogova (1960, p. 77) ccnsidered Stereoxylodes as a mainly solitary form with rare budding, and described a solitary species, S. carinatum, from the Chagyr Suite (Upper Wenlock) of South-west Siberia. This form, however, has only weakly developed carinae and little dilation of the septa and so is only doubtfully considered as a representative of Stereoxylodes, being perhaps more likely to be a representative of Entelophyllum. Strelnikov (1964), p. 57) considered the genus contained only solitary forms and Ivanovskiy (1965a), p. 71) suggested that the name Stereoxylodes be reserved for solitary forms witn the morphology of that genus, compound representatives being included in the genus Carinophyllum Strelnikov, 1964. This latter form is discussed below. Sytova (1970, p. 70) modified Stereoxylodes still further, considering it contained forms either solitary or rarely forming a “ pseudocolony ” She also stated that the primary septa consisted of a fan-shaped arrangement of radiating trabeculae. This latter feature could represent a vertical section intersecting the carinae, such a structure being typical of carinate forms (e.g. Heliophyllum Hall; Smith, 1945, Plate 33, Figure 3b). Sytova considered also that a peripheral zone of dilated septa and scler- enchymal tissue was confined to the early growth stages only, and this is generally found in described species, although S. pseudodianthus sinense Wang, 1944 has a prominent peripheral stereozone in mature stages. Wang’s material is probably atypical of the genus but there does not seem sufficient evidence at this time to exclude his subspecies from the genus, although 62 this was suggested by Sytova (1970, p. 71). The form described by Sytova (1970, p. 71) as S. minimus is mainly a solitary form, but does occur as branching colonies. The genus Ramulophyllum Nikolaeva, 1964, was originally described (Nikolaeva, 1964, p. 52) as a solitary form, with thick, carinate septa and a dissepimental and tabular structure similar to that described for Stereoxylodes. The form described by Sytova (1968, p. 62) as R. explicatum from the Skala Horizon (Upper Ludlow—Lower Pridoli) of Podolia has thinner, more complete septa than is typical of Ramulophyllum. Nikolaeva (1964) described six new species of Ramulophyllum from the Aynasuy Horizon of Central Kazakhstan (con- sidered Upper Silurian by Ivanovskiy, 1965) and basal Devonian by Hill, 1967). Of the species, R. heterozonale (type species), R. heliophylloides and R. parvum in particular appear to show very similar structure to that of Stereoxylodes. The major difference appears to lie in the more degenerate peripheral septal structure shown in Ramulophyllum. The septa appear to break down into separate “ strands ”’ with irregularly oriented septal lamellae, giving the appearance of rather large, randomly inclined carinae. Very small globose dissepiments appear to be “clustered” around the septal lamellae in forms showing greatest breakdown of septa. These features are shown especially in the Czechoslovakian “ R.”’ prosperum (Potta, 1902) (see Prantl, 1940, Figures 6-8). This species was listed as a possible synonym of Stereoxylodes by Ivanovskiy (1965b), and con- sidered congeneric with S. pseudodianthus by Prantl (1940). However, this feature appears to be a further development of the formation of dilated, carinate septa found in representatives of Stereoxylodes, the specimens of Stereoxylodes pseudodianthus figured from the Wenlock of England by Lang and Smith (1927, p. 475, Figure 15) and Lower Ludlow of Estonia (Ivanovskiy, 1965a, Plate XIX, Figure 2) showing some peripheral septal breakdown of this type. Hence it seems reasonable to include Ramulophyllum as a synonym of Stereoxylodes, although forms with more degenerate septa should perhaps be included as a subgenus of Stereoxylodes. For the _ present, however, Ramulophyllum is included with reservations as a synonym. Nikolaeva (1964) also described the new genus Ornatophyllum from the same _ horizon as Ramulophyllum. According to Nikolaeva the distinguishing features of the former were the major septa being longer than in Ramulophyllum, R. A. McLEAN forming an axial complex. The length of septa in described species of Stereoxylodes is variable although they generally extend to near the axis, — but the presence of septal lamellae which may — form a weak axial complex may be enough to distinguish the genus. In all other respects, © particularly the dilated, strongly carinate septa, ~ Ornatophyllum seems comparable to Stereoxy- lodes. Its position is unresolved. ! } The position of the genus Carinophyllum | Strelnikov, 1964, is not certain. originally described as a_ solitary (Strelnikov, 1964, p. 59), but the type species” then designated, Cyathophyllum confusum Poétta, 1902 from the Upper Silurian (Budnany) of | Czechoslovakia, is colonial (see Poéta, 1902, | Plate 99, Figure 3-11). C. confusum was considered congeneric with S. pseudodianthus by Prantl (1940). In internal morphology the genus is very similar to Stereoxylodes, differing in having very strongly dilated septa that are greatly thickened with schlerenchyme. As men- tioned above, Ivanovskiy (1965a) suggested that the name Carinophyllum be used for compound forms having the internal morphology of Stereoxylodes and subsequent workers have | recognized colonial representatives of Carino- phyllum only (see Shurygina, 1968, p. 78). Whether the presence of abundant sclerenchymal © thickening of the septa in Carinophyllum is due to environmental factors or is a feature peculiar to that particular genus and is thus of taxonomic importance is not certain. If the latter is the” case, then subgeneric status seems the most useful classification cf “ Carinophyllum”’. Range : Upper Llandovery of N.S.W. ; Wenlock of England, Germany (drift), Czechoslovakia and ?China; Upper Silurian of Estonia, Czechoslovakia, ? Poland, Podolia, ? Turkey, Urals, Subpolar Urals, Vaygach Island and Kazakhstan. Foe te ET Stereoxylodes multicarinatus sp. nov. Plate IV, Figures 3-10; Plate V, Figure 2 Derivation of name; After the strongly carinate nature of the septa, particularly in the axial! zone. Material: Holotype SUP 46184, Paratypes SUP 46185-46187. SUP 46188 is doubtfully” included in the species. Rosyth Limestone, | Boree Creek area. Upper Llandovery. Diagnosis : Solitary, trochoid Stereoxylodes with septa strongly carinate with spinose projections, particularly in tabularium in late growth stages, and marked peripheral breakdown of septa. | Major septa reach axis. §) carinae. LOWER SILURIAN RUGOSE CORALS FROM CENTRAL NEW SOUTH WALES 63 Tabulae divided into strongly arched axial series and concave periaxial series; dissepiments numerous, small and slightly elongate. Description: Solitary, trochoid corallum with diameter ranging from approximately 30-45 mm Corallum height of approximately 40 mm in small relatively incomplete specimen (SUP 46188). Epitheca generally not preserved, but where present (in probable representative of S. multicarinatus, SUP 46188) it is mainly smooth with faint horizontal wrinkles and pronounced septal grooves. Calice shows a pit with depth of about 18 mm in largest specimen | (SUP 46185), with diameter 15 mm at base and 25 mm at rim, where overall corallite diameter ‘is 45 mm. Sides of calical pit steep, with ' slight development of broad boss at base of pit. Wide calicular platform present which is flat or slightly arched. Maximum septal number of approximately 90 in largest specimen (incomplete, SUP 46185), and generally ranges from 80-86 in smaller forms. Septa of two orders, major septa extending or almost extending to corallite axis, where weak twisting of septal ends may occur. Major septa withdrawn from axis in earlier growth stages (see Plate IV, Figure 6). Carinae generally strongly developed, particularly on major septa, and in longitudinal section (e.g. ‘)) Plate IV, Figure 10) can be seen to consist of spines or denticles, at least on their outer edges. Carinae generally almost perpendicular to septal lamellae in axial region but usually more oblique in dissepimentarium, forming typical zig-zag Septa strongly thickened in dis- sepimentarium but major septa taper towards axis. However, towards outer margin of dis- sepimentarium, septa lose their solid structure and break down to give retiform appearance, consisting of thin septal lamellae and carinae with occasionally clusters of small dissepiments around these elements. This structure is illus- trated in Plate IV, Figure 3. Minor septa are thinner than major septa and approximately 0-3-0-4 of length of major septa. Tabularium wide, at least half diameter of corallite, composed of narrow periaxial series of strongly concave, incomplete tabulae and }| strongly arched axial series consisting of large, | globose tabellae at margin and slightly sagging | (see Plate IV, Figure 9). incomplete tabulae and tabellae in the centre Dissepiments small, | globose or weakly elongate, very steeply inclined §;so as to be almost parallel to corallite wall. Average dimensions 0:8-1:0 mm wide and 0-4 mm high. Ontogeny : Although only a few specimens are available for study and the material is very incomplete preserved, some comments may be made on the morphological changes during growth of the form, owing to the different growth stages preserved in different specimens. The earliest stage preserved (? early neanic) is represented in SUP 46187a (Plate IV, Figure 6) where at a corallite diameter of 13 mm, 68 septa are present. At this level, the major septa are somewhat withdrawn from the axis, although a few isolated, wavy septal lamellae extend into this zone. The septa are quite strongly dilated, especially near the periphery and carinae are well developed though widely spaced. Peripheral breakdown of the septa can be detected but the material is incomplete in this region. Minor septa are very short although periphery of specimen is not preserved. A late neanic or early ephebic stage is repre- sented in SUP 46184a (Plate IV, Figure 9) where at a corallite diameter of 25 mm, 84 septa are developed. At this stage the major septa reach the axis and are slightly twisted. The major septa are moderately dilated and solid near the inner margin of the dissepimentarium, tapering towards the axis and remaining dilated but breaking up into the retiform condition towards the periphery. Septa are moderately carinate throughout and minor septa extend up to half length of major septa. A late ephebic stage is represented in SUP 461855 (Plate IV, Figure 5), sectioned just below the calical pit where the corallite diameter is 36 mm and septal number 90. Major septa are strongly dilated, tapering only near the axis, where they meet. Carinae are very numerous and septa are broken down to a retiform condition in most of the dissepimentarium. Where the septa are “ solid” (near dissepiment- arial—tabularial boundary) they appear to be thickened with sclerenchyme which decreases towards the periphery, exposing the retiform condition. Minor septa are at least half the length of the major septa. Remarks: None of the described species of Stereoxylodes show any very close similarities to S. multicarinatus sp. nov. It is a larger species than any described, the only species approaching it in dimensions being S. prosperus (Poéta, 1902) from the Upper Silurian (Budnany) of Czecho- slovakia. Other similarities to this spécies include the strongly carinate, dilated septa breaking down into a reticulate structure peripherally and the shape and disposition of It may, however, be dissepiments and tabulae. 64 R. A. McLEAN clearly distinguished from S. multicarinatus by possessing offsets and shorter major septa and lacking carinae in the axial region. The type species, S. pseudodianthus (Weissermel, 1894), has long septa as in S. multicarinatus and very strong development of carinae, although this is not as pronounced as in S. multicarinatus in the axial zone, but the septa are not as strongly dilated in the dis- sepimentarium and peripheral breakdown of septa is not as pronounced (see particularly Lang and Smith, 1927, p. 475, Figure 15). Specimens of Strombodes rosythensis sp. nov., described below, may show development of carinae similar to those of Stereoxylodes multi- carinatus, but they are generally more weakly developed in the former (see Plate VI, Figure 3). The N.S.W. occurrence of Stereoxylodes is apparently the oldest recorded at present. The genus first appears overseas in the Wenlock of Europe and is most common in the Upper Silurian of Eastern Europe and Central Asia. ? Stereoxylodes sp. Plate IV, Figure 11; Plate V, Figure 1 Material : SUP 46189 Rosyth Limestone, Boree Creek area, Upper Llandovery. Description : Solitary, trochoid corallum with maximum corallite diameter of 42 mm. Calice similar to that in S. multicarinatus sp. nov. Septal number 86 at corallite diameter 32 mm. just below base of calice. Major septa long, reaching axis, where they show marked twisting, Septa strongly dilated in dissepimentarium, tapering towards axis and showing marked peripheral breakdown as in S. multicarinatus. Carinae only weakly developed, particularly on axial side of peripheral breakdown of septa. Minor septa approximately 0-3 length of major septa. Tabularium incompletely preserved but there appears to be less strong differentiation into an axial and periaxial series of tabulae. Strongly arched series of tabellae at least are present. Dissepimentarium only partly present in imperfect longitudinal section, but size and disposition appears similar to that in S. multicarinatus sp. nov. Remarks: This specimen differs from S. multicarinatus sp. nov. only in the prominent twisting of the axial ends of the major septa and the weak development of carinae. It shows similarities to Ptychophyllum Edwards and Haime, 1850, in possessing an axial vortex and the dilated septa, but the presence of carinae, although weak, and the much more pronounced peripheral breakdown of the septa serve to distinguish it. It may represent an aberrant form of S. multicarinatus, but until — the species can be studied in more detail witha § larger number of specimens, its taxonomic § position remains unresolved. Family Uncertain Discussion: The suprageneric status of | Strombodes Schweigger, 1819, is at present § , uncertain. Previous authors have included it 9 as a representative of various families of the - suborder Columnariina Rominger, 1876 (e.g. Chonophyllidae Holmes: Hill, 1956; Kaljo, 1958 ; Spongophyllidae Dybowski: Ivanovskiy, © 1965a). However, Strombodes shows very close similarities to the genus Entelophyllum Ny Wedekind, 1927, a _ representative of the ii Arachnophyllidae (suborder Streptelasmatina). Entelophylium, as defined by Sytova (1952) and Ivanovskiy (1963a@ and }) is taken to include massive, fasciculate and solitary coralla with lamellar septa, horizontal convex or convexo- concave, often incomplete tabulae and usually small, globose dissepiments that may be excep- tionally lonsdaleoid. Hence the only significant | difference between this genus and Strombodes © seems to be that the latter has typically well- developed lonsdaleoid dissepiments that are elongate rather than globose. Therefore it does not appear justified to separate Strvombodes and Entelophyllum into separate —_ suborders. Equally, however, the view of Ivanovskiy (1965a) whereby Arachnophyllum and Entelo- phyllum were grouped in the Columnariina (family Arachnophyllidae) together with Strombodes (family Spongophyllidae), while typical Arachnophyllid forms Ptychophyllum and Cyathactis were included in the Strep- telasmatina (family Ptychophyllidae), does not appear acceptable. A restudy of these and related forms would appear essential before | this taxonomic problem can be resolved. Genus Stvombodes Schweigger, 1819 21927 Kyphophyllum Wedekind, p. 19. &y 21937 Kyphophyllum ; Soshkina, p. 27. " 21927 Tenuiphyllum (part.) Soshkina, p. 31. .. 21944 Kyphophyllum; Wang, p. 26. + 21949 Cyathophyllum (part.); Amsden, p. B,,. 108 (non Goldfuss, 1826). it. 1955 Evenkiella (part.) Soshkina, p. 126. 21958 Kyphophyllum ; ‘Kaljo, p. 107. h 1962 Tabulophyllum; Ivanovskiy, p. 120 (non Fenton and Fenton, 1924). 1963a Evenkiella; Ivanovskiy, p. 80. LOWER SILURIAN RUGOSE CORALS FROM CENTRAL NEW SOUTH WALES 65 1963b Evenkiella; Ivanovskiy, p. 88. ?1963b Tenwiphyllum ; Ivanovskiy, p. 90. 21965 Strombodes; Stumm, p. 47. 1965a Strombodes ; Ivanovskiy, p. 116 (cum syn.). 1965 Fepphotheissih Strelnikov, p. 40. 1966 Strombodes; Sytova and Ulitina, p. 233. 21968 Evenkiella; Lavrusevich, p. 115. 21970 Strombodes (Kyphophyllum); Fligel and Saleh, p. 281. 21970 Tenuiphyllum; Fliigel and Saleh, p. 284. 1971 Strombodes ; Strelnikov, p. 79. 21972 Kyphophyllum ; Merriam, p. 36. 1973 Strombodes; Strelnikov, p. 49. non 1960 Evenkiella; Zheltonogova, p. 86. Type species: Madrepora stellaris Linnaeus, 1758, Slite Beds (Wenlock), Gotland. Diagnosis: Fasciculate, massive or ? solitary corallum. Septa of two orders, usually thin, characteristically lonsdaleoid near periphery of corallite. Tabulae complete and incomplete, commonly domed. Dissepiments usually elongate. Discussion: The genus Kyphophyllum was erected by Wedekind (1927) and subsequently revised by Sytova (1952). Wedekind’s material consisted of both solitary and compound forms (Wedekind, 1927, p. 19). However, Sytova (1952) included only compound forms, with the following diagnosis (summarized) : “ fasciculate colonies, with thin, sometimes discontinuous septa, strongly convex tabulae and _ large, flattened, often lonsdaleoid dissepiments’”’. On such a basis, there seems little reason to doubt that Kyphophyllum is synonymous’ with Strombodes, a view held by Smith (1945), Wang (1950) and Ivanovskiy (1965a). Fliigel and Saleh (1970) suggested that Kyphophyllum be §) considered a subgenus of Strvombodes on the basis of Kyphophyllum being a solitary form. There has been no consistency in the past as to how forms with similar internal morphology, but having both solitary and compound coralla, should be classified. In the main, both solitary and compound forms have been grouped in the one genus, so until a definitive statement is made .on this subject, it seems best to follow this viewpoint. Accordingly Kyphophyllum is here included as a probable synonym of Strombodes. The genus Evenkiella Soshkina, 1955, was §} erected to include forms having colonial coralla, |i} thin lamellar septa, flattened convex tabulae which are usually incomplete, together with E ye 4 te : 4 large, lonsdaleoid dissepiments (Soshkina, 1955 and Ivanovskiy, 1963a and b). On the basis of the variability within the similar genus Entelophyllum, as described by Sytova (1952) and Ivanovskiy (1963a@ and 6), it seems reason- able to regard Evenkiella as a junior synonym of the genus Strombodes, as defined above. Ivanovskiy (1965a, p. 85) recognized a relation- ship between Strombodes and Evenkiella by placing the latter in the family Spongophyllidae as well, but still considered them separate genera. To the genus Tenwphyllum Soshkina, 1937, as redefined by Ivanovskiy (1963), p. 90), were assigned forms having massive coralla, occasion- ally lonsdaleoid septa, convex tabulae and numerous, rather small dissepiments. The characteristic feature was development of an “internal wall’’ from lamellar sclerenchymal thickening of the septa to make them laterally contiguous at some part of their length. Wang (1950) considered Tenuiphyllum a synonym of Entelophyllum but the genus shows similarities to both cerioid Strombodes and Entelophyllum, and probably is closer to Strombodes in rather commonly showing elongate _lonsdaleoid dissepiments. Soshkina et al. (1962, p. 319) considered Tenuiphyllum synonymous’ with Kyphophyllum and Sytova (1952) included the species TJ. flexuoswm Soshkina, 1937 in Kyphophyllum. However, Fliigel and Saleh (1970, p. 284) believed Tenwiphyllum constituted a distinct genus. The “internal wall’’ may distinguish it as an aberrant form of Strombodes but the described species need to be studied in more detail before their true taxonomic status is clarified. The systematic position of the genus Micula Sytova, 1952, is uncertain. The name was proposed for forms having solitary, cylindro- conical coralla; long septa of two orders ; arched, incomplete tabulae and small globose dissepiments. The lack of budding in this form was used to distinguish it from Entelophyllum. However, lonsdaleoid septa may be present in some specimens (Sytova, 1952) and it seems the genus may represent an intermediate between true Entelophyllum and Strombodes. Sytova (1952) suggested that the solitary species, “ Kyphophyllum primaevum”’ described by Wang (1944), belongs to either Micula or an intermediate between Micula and Kyphophyllum. It is possible that forms apparently possessing solitary coralla and previously included. in “ Kyphophyllum”’ (K. cylindricum Wedekind, 1927 ; K. conicum Wedekind, 1927; K. tenue Wedekind, 1927; K. multiseptatum Soshkina, 66 R. A. McLEAN 1937 ; K. primaevum Wang, 1944; K. schmidti Kaljo, 1958), could perhaps be included in Micula, if one considers that solitary and compound forms should not be grouped in the one genus although this does not seem a useful distinction. The systematic position of these species and of Micula itself for the moment remains unresolved. Range : Upper Ashgill of Estonia ; Llandovery of Estonia and ? north-east Iran; Upper Llandovery of Siberian Platform and N.S.W., Wenlock of Gotland, northern Urals, Subpolar Urals and Siberian Platform ; Upper Silurian of Estonia, northern Urals, Arctic U.S.S.R. (Chernov Ridge), Kazakhstan, ? California and ? Nevada. Strombodes rosythensis sp. nov. Plate V, Figure 3-6; Plate VI, Figure 1-5 Derivation of name: After the type horizon, the Rosyth Limestone. Material: Holotype SUP 45217, Paratypes SUP 25165, 45218-45227, Rosyth Limestone, Boree Creek area, Upper Llandovery. Diagnosis: Phaceloid or partially cerioid Strombodes with parricidal and non-parricidal calicinal increase. Average corallite diameter of 13 mm., septa commonly showing dilation and weak ? carinae in dissepimentarium. Dissepiments in broad zone, with at least five rows. Description : Corallum colonial, both phaceloid and cerioid. Corallites commonly fasciculate immediately after budding. Adjacent corallite walls usually in contact, or periodically so, giving cerioid transverse section during later ontogeny. Epitheca thin, with faint vertical septal striations and horizontal imbricating rings, representing impressions of dissepiments. Transverse wrinkling and rejuvenescence fre- quently shown. Corallites cylindrical, showing polygonal transverse section when cerioid. Colonies may reach size of 60 cm or more in width and 30 cm in height. Corallite diameter may increase gradually from very narrow initial stage (1-2 mm) with sudden increase in mature dimensions (average 13 mm) or may never reach normal maximum size owing to crowding by adjacent larger corallites. Maximum diameter observed, 18 mm. Growth commonly ceases at a particular level in adjacent corallites, some then sending out buds. Increase invariably calicinal, usually from outer rim of calice, although occasionally from central pit (in this case it is probably simple i t rejuvenation). At least six offsets observed } 4 from one calice during ontogeny in corallites } , showing rejuvenescence (Plate V, Figures 3, 4). a Increase is mostly non-parricial since rejuvenes-_ cence almost always occur at time of budding. — Calice deep, with broadly flaring, flattened margin, average diameter of calicular pit 7 mm, - depth 4-5 mm. Axial boss in pit average 4 mm wide, with height 1-2 mm. Septa usually lonsdaleoid, average number 52 (maximum observed 62). Major septa reach almost to axis. In late ontogeny weak axial vortex may occur, with septa reaching almost | to axis. Major septa generally thickened i dissepimentarium and may show weak zig-zag | j. ? carinae. Minor septa generally weakly) developed, strongly lonsdaleoid, rarely extending © into tabularium. Minor septa do not appez to be distinguishable until a diameter of approx imately 7 mm is reached (although silicification tends to obscure most detail in immature © stages). In longitudinal section (Plate V, Figure” 6), possible trabecular nature of septa shown b short spines arising from dissepiments (including also oblique intersections of septa). Being perpendicular to dissepimental surface, the are gently inclined towards corallite axis. Tabulae incomplete mainly, strongly distally arched in axial region with sagging latera margins. Central area flattened, with slight axial depression, or composed of imbricating subsidiary tabellae. Tabularium average diameter 4:5-5 mm, tabular spacing 0- 0-5 mm. Dissepiments mainly elongate tending to be more globose in inner area of dissepimentarium. In peripheral area, maxi mum width of dissepiments reaches approxim: ately 2-5 mm, decreasing axially to more globose types of width 0:5 mm. Average dissepimental height 0-4-0-5 mm. _ Dissepi ments commonly in 5-6 rows, gently inclined towards axis, becoming steeper near tabularia margin. df to ‘] Remarks: Only three species of Strombode show much similarity to the Rosyth fo S. socialis (Soshkina, 1955), from the Upper} Llandovery of the Siberian Platform and t Lower Wenlock of the Urals is comparable te B the local species in its phaceloid growth form} Ku, and non-parricidal increase, strongly lonsdaeloi¢ ? septa and elongate dissepiments and tabula : form (see Soshkina, 1955; Ivanovskiy, 1965a 1 Strelnikov, 1971). In particular thelongitudinaly | section figured by Soshkina (1955, Plate XII : Figure 2) is very similar to that of the Ros ; species. However, S. socialis may be dis P, LOWER SILURIAN RUGOSE CORALS FROM CENTRAL NEW SOUTH WALES 67 tinguished by much larger dimensions (up to 30-40 mm corallite diameter) a larger number of much thinner septa (70) and a greater number of dissepiments (10-15 rows). S. elkinense (Sytova, 1952), from the Wenlock of the Northern Urals shows strong similarities to S. rosythensis in its manner of increase, with formation of offsets from the rim of the old calice at the time of rejuvenescence (Sytova, 1952). It is also comparable to the Rosyth form in corallite dimensions, septal number and septal form. However, it may be distinguished by having thinner septa, a wider tabularium with more widely spaced tabulae and fewer, more globose and more steeply inclined dissepiments. Acknowledgements The writer is grateful to Dr. B. D. Webby for c1itical review of the manuscript. The project was partly supported by a Commonwealth Postgraduate Studentship at the University of Sydney. References In order to save costs some publications have not been cited in the bibliography. These are included in Cotton, G. (1973). AmspDEN, T. W., 1949. Stratigraphy and Paleontology of the Brownsport Formation (Silurian) of Western Tennessee. Bull. Peabody Mus. nat. 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Obersilurische und devonische Korallen, Stromatoporoiden und Trepostome von der Prinzeninsel Antirovitha und aus Bithynien. oHAEL Palaeophyllum sp. cf. P. thomi (Hall) 1857 Plate Ik—n, Figure 4 Material: Eleven specimens, UNE F11581-91, from which ten transverse and ten longitudinal sections were prepared, from Locality 841, lenses A and B, Uralba Beds. Two transverse and two longitudinal sections, UNE F11791-2, cut from material no longer extant, from Locality 842, Trelawney Beds. MAJOR SEPTA @ eeceeeeem 00 OF NUMBER 2 4 6 CORALLITE DIAMETER (MM) Ficure 4.—Palaeophyllum sp. cf. P. thomi (Hall). Scatter diagram of number of major septa x diameter. (1) from Trelawney Beds; @ from Uralba Beds. Description : Corallum of phaceloid, cylindrical corallites of small diameter; corallites free for greater part of length, sometimes twisting but generally subparallel. Adjacent corallites may be in contact for short distances where out- growths from the epitheca connect the walls ; in transverse section this produces what appear to be short, cateniform chains of up to four corallites. However, connecting tubes, as seen in Syringopora, are not seen. Increase by lateral budding, non-parricidal. Corallite diameters range from 2-1 to 4-6 mm with a thick peripheral stereozone from 0-2- 0-4 mm thick. Major septa range in number from 16 to 22; long, straight, of even thickness, reaching almost to the axis where the tips of groups of septa may be fused. Septal counts at various diameters are: 2:5 mm, 16-18; 3-0 mm, 17-21; 4-0 mm, 20-21 (see Fig. 4). Minor septa incompletely developed, with only a few seen in any section, and often completely absent ; when present appear as short, blunt spines extending just beyond the stereozone. Tabulae closely spaced, 9-12 in a length of 5 mm; complete; highly arched with axial notch, or flat and gently depressed axially with strongly downturned edges. Remarks : The present material agrees closely with the descriptions and figures of the holotype given by Hill (1959). Flower (1961) describes P. thomi from New Mexico in which the tabulae show wide variations in form, as described for the present material. Bee er Se Peete iane rer Palaeophyllum trelawneyense sp. nov. Plate Io-q; Figure 5 Name Derivation: Named after the Trelawney Beds from which the type material was collected. a vee me Material: Five transverse and three longitudinal sections, numbered UNE F11744/1-8, cut from the holotype, of which hand-specimen material is no longer extant. From Locality 842, Trelawney Beds. —— - - ven a erie 1 ow @ re NUMBER OF MAJOR SEPTA o 2 3 4 > 6 CORALLITE DIAMETER (MM) Figure 5.—Palaeophyllum trelawneyense sp. nov.) Scatter diagram of number of major septa x diameter, jf Description: Phaceloid ; corallites cylindrical } with lateral, non-parricidal increase. Corallites * circular in cross-section; 3°0 to 4-6 mm in diameter with a peripheral stereozone 0-4 0-5 mm wide. Major septa long, thin, extend- Se | ing almost to the axis where the tips are fused in irregular groups; number of major septa 16-21. Minor septa have not been observed. Tabulae variable in form: gently arched or sagging axially, with edges turned upwards or downwards; 10 tol5 ina length of 5 mm. Remarks : Compared with the other species of this genus from the Uralba Beds and Trelawney Beds, this species is most closely allied with P. sp. cf. P. rugosum but is distinct from that species in having smaller average corallite diameters with fewer septa, in lacking the development of minor septa altogether and in having more closely spaced and variable tabulae. In general dimensions, number of major septa and spacing of tabulae this species is very similar to P. macrocaule Webby, but the relatively long minor septa of that species are not developed. Webby also describes the frequent elongation of one septum to form “ an axial, columella-like structure ’’ (1972, p. 154); this feature is not seen in P. trelawneyense where all the major | septa are long, extending almost to the axis. | Ontogeny in Palaeophyllum: Serial section | examination of the budding in two species | (P. sp. cf. P. rugosum and P. bothroides) shows that in both increase is lateral and non-parricidal. | Only a single daughter corallite is formed, | though in one case two were observed to form simultaneously. The daughter corallite is formed almost entirely external to the normal edge of the parent calyx by an outward swelling of the parent wall. The partition dividing the parent from the daughter corallite is formed by the swelling of the peripheral ends of about four of the septa in the parent corallite. After an early aseptate stage the long cardinal septum is the first of the protosepta to appear and may later extend right across the daughter corallite. Bulges on the wall Tepresenting the alar septa appear next. Insertion of metasepta in the cardinal quadrants is usually accelerated, these often appearing before the counter septum is finally developed. The daughter corallite usually remains in contact with the parent for a length of 3-4 mm, separating just before the Maximum number of septa is formed. Genus : Cyathophylloides Dybowski 1873. Mlype Shecies: Cyathophylloides kassariensis ® Dybowski 1873. Discussion: The genus Favistella Dana 1846 was based on the genotype Colwmnaria alveolaris "@Van Cleve, but Van Cleve’s description was never published. Later workers generally used the genus as Favistella Hall 1847 which had as its type species Favistella stellata. Bassler F ot} all ith ely (pe bes | lae |] the UPPER ORDOVICIAN CORAL FAUNAS FROM NORTH-EASTERN N\S.W. 81 redefined the genus Favistella, accepting F, alveolata Goldfuss as the type species, but Flower (1961, p. 76) points out that the original description of this species was so general that much confusion arose in subsequent species identification. He thus proposed the new name Favistina, based on F. undulata Bassler, for the group of Ordovician corals formerly included under the name Favistella Bassler. Spjeldnaes (1964) described Cyathophylloides kiaerty with characters intermediate between those of Cyathophylloides and Favistella. Simmons and Oliver (1967, p. 10) suggested that the name Favistina Flower ought to be utilized for such intermediate forms, as it is based on a well known type species, whereas the type species of Cyathophylloides is not well known. Browne (1965, p. 1186) described species of Favistina Flower which possessed features in common with both Favistella Dana and Cyathophylloides Dybowski. She then proposed enlarging the scope of the genus Cyathophylloides Dybowski to include Favistella Dana (=Favistina Flower). This usage is followed here. Cyathophylloides sinuata sp. nov. Plate IIa, b Name Derivation: Latin sinuatus=waved. A reference to the form of the corallite walls. Material: Twenty-two specimens: UNE F11610-23 from Locality 841, lenses A and I, Uralba Beds; UNE F11696-9 from Locality 842, Trelawney Beds. From this material fifteen transverse and_ sixteen longitudinal sections were cut. UNE F11698 designated holotype. Description : Corallum massive, corallites cerioid with thick walls (0-15 to 0:5 mm) which are generally crenulate in cross-section, with a dark axial plane present; wall segments curved. Corallite diameters variable within each corallum, ranging from 2-1 to 5-3 mm. Major septa long and thin, 11-15 in mature corallites, reaching almost to the axis where the tips may be fused in irregular groups or interfinger, becoming twisted ; occasionally withdrawn. Minor septa well developed, ranging in appearance from short, blunt spines extending just beyond the stereozone, to thin spines up to half the length of the major septa. Tabulae broadly domed, often with axial depression and edges strongly downturned : rarely incomplete ; spacing varies between 9 and 18 in a length of 5 mm, though crowded zones are not developed. 82 RUSSEEL /L;, 4HAEL Remarks: This species is similar to that described as Cyathophylloides cf. C. burksae Flower by Browne (1965, pp. 1189-9), but differs in having tabulae twice as closely spaced and lacking crowded zones. C. neminghensis (Etheridge) 1918 differs from the present species in having fewer septa (only 7-10 major) and tabulae more widely spaced, with 6 in a length of 5 mm, generally horizontal. Cyathophylloides juncta sp. nov. Plate IIc, d; Figure 6 Name Derivation: Latin junctus=united. A reference to the fusing of the tips of the septa. FIGURE 6.—Cyathophylloides juncta sp. nov. (A) UNE F11701/2 (holotype), T.S., x3; (B) UNE FI1701/1 (holotype), L.S., x8. Material: Four specimens, UNE F11700-3, from which four transverse and five longitudinal sections were cut. From Locality 842, Trelawney Beds. Holotype is UNE F11701. Description : Corallum massive, corallites cerioid with thick walls (0-2-0-5 mm) ; wall segments curved ; walls crenulate with a dark axial plane. Corallites polygonal in cross-section, 5 to 7 sided, varying in diameter between 1-7 and 3:0 mm. Major septa long, usually extending to the corallite axis where the tips are twisted together and fused to form a_ loose, “columella ’’-like structure; the number of major septa varies from 10 to 14 in mature corallites. Minor septa consistently developed, thin, varying from short spines which extend only about 0-1 mm _ beyond the peripheral stereozone to those extending half the distance to the axis. Tabulae strongly arched and _ tent-shaped, rising to a maximum height at position of “columella’’ where they are frequently dis- rupted; unevenly spaced with 10-22 in a length of 5 mm. Remarks: This species differs from C. sinuata in the presence of the loose “ columella ”’ formed by the fusion and twisting of the tips of the major septa at the axis and also in the more strongly inclined tabulae. Average diameter of the. corallites in this species is smaller than in ~ C. sinuata. Genus: Crenulites Flower 1961. t Type Species: Crenulites duncanae Flower \§h 1961. : Crenulites australis sp. nov. { Plate Ile, f Name Derivation: Latin australis=southern, referring to the first occurrence of this North American genus in Australia. Material: Five specimens, UNE F11624-28, @\ from Locality 841, lens A, Uralba Beds; eight © specimens, UNE F11704-11, Locality 842, | Trelawney Beds. From this material twenty- two transverse and twenty longitudinal sections were cut. UNE F11705 designated holotype. , Description: Corallum massive, broad and bs flattened, up to 10 cm across and reaching 5 cm § jy in height. Cerioid, corallites slender and radiat- 1 ing slightly from the base. Corallites polygonal, ti with diameters between 1-4 and 2:4 mm, with a straight or slightly wavy wall segments showing tir a dark axial plane. Walls 0-06-0-2 mm thick. Septa amplexoid, of variable appearance in 4 cross-section ; 14-16 in each corallite. Close 4 to anterior surface of tabulae the eight or nine P major septa reach almost to the corallite centre, being straight and of even thickness. Minor septa are invariably present in such sections as very short stubs. In other sections two orders” of septa are not able to be distinguished, all appearing as short stubs; in some sections septa are not seen. : Tabulae widely and evenly spaced, 6-9 in a | length of 5 mm; horizontal or gently arched, | with downturned edges; in some transverse | sections the scalloped nature of the tabulae neal a the walls can be seen as they pass in and out of | the plane of section. Longitudinal sections | passing close to the walls show the tabulae wit . short prolongations on their upper surface i (representing the cut ends of amplexoid septa) | which do not reach the tabulum next above, | though become longer as the wall is approached. + Remarks : C. australis differs from the six known | species belonging to this genus (all described ” from North America) in having smaller corallites. | It is most closely allied to C. duncanae Flower in | size, but differs from that species in regular] SS A a AE RC ET OR VERS ine YAY Oe es em wero UPPER ORDOVICIAN CORAL FAUNAS FROM NORTH-EASTERN N.S.W. possessing eight or nine septa and in having more widely spaced tabulae which lack any | zones of crowding. ey Crenulites australis minor sp. et subsp. nov. : Plate IIg, h Material: One specimen, UNE [11712 (holotype), from which two transverse and two | longitudinal sections were cut. From Locality 842, Trelawney Beds. Remarks: This form is very similar in most | aspects to C. australis sp. nov. and so is not fully described. It differs from that species in having corallites of consistently smaller i} diameters, being 1-0 to 1-5 mm across. "| Suborder: Streptelasmatina Wedekind 1927. || Family: Streptelasmatidae Nicholson in Nicholson and Lydekker 1889. , 2 “ Streptelasmatid gen. et sp. indet ” ty Plate Ili-l Remarks: Two fragments from Locality 842, Trelawney Beds and one from Locality 841, th) Jens K, Uralba Beds (thin sections numbered ult, UNE F11687-9 and UNE F11738 respectively). 1 _ The form from the Uralba Beds is a large ‘fl solitary corallite which has been compressed ; mii smaller diameter is 11-4 mm. Septa wavy, 7 thin, withdrawn from the axis, numbering 70, ¢ with two orders distinguishable ; axial structure a not apparent. in (Plate IIk). inf}. there are two forms present in the material in from the Trelawney Beds. The first is a solitary af corallite 9-6 mm in diameter with 29 major gi Septa which extend only two-thirds of the #idistance to the axis and thicken markedly jpg towards the wall. Corallite wall thick, up to }1-5 mm, and the minor septa appear as short _ §istubs on the inner surface of the stereozone. "\Tabulae apparently domed and incomplete he (Plate Ili, 1). The second form from the (“§\Trelawney Beds is a solitary corallite 10-6 mm ‘Sin diameter with thin wall (up to 0-5 mm) and tS long, thin major septa which extend almost "Sito the axis where the tips may be fused in small ‘"Sgroups. Minor septa well developed, up to ‘ one fifth the length of the major septa (Plate IIj). epld holder: Tabulata Milne-Edwards and Haime cid 1850. Er amily : Syringophyllidae Pocta 1902. vg ubfamily : Syringophyllinae Pocta 1902. iit\Genus : Calapoecia Billings 1865. WT vpe Species: Calapoecia anticostiensis Billings ult BL 865 Wall thin, averaging 0-4 mm 83 Calapoecia canadensis Billings 1865 1865 Calapoecia canadensis Billings, p. 426. 1957 Calapoecia aff. canadensis Billings; Hill, p. 101; Plate III, Figures 14a, b. (For a complete synonymy see Cox, 1936, p. 7.) Calapoecia sp. cf. C. canadensis Billings 1865 Plate IIIa, b; Figures 7, 8 Material: Four silicified specimens, UNE F11592-5, from which three transverse and two longitudinal sections were prepared. From Locality 841, Uralba Beds, lens I. Descriplion : Corallum massive, 15 cm high by 20 cm wide and 5 cm thick. Corallites radiating from base, polygonal or rounded in cross-section, arte ty = J e = ce °g ° Mm? = * oS sre y a FIGURE 7.—Calapoecia sp. cf. C. canadensis Billings. UNE F11592/1, T.S., x65. 2:0-2-5 mm in diameter and closely spaced, with centres never more than 3-0 mm apart. Corallites separated by a wall 0-2 to 0:5 mm thick, being wider at the corners between corallites to produce the rounded appearance of the corallites in cross-section. Short spines, reaching only about one fifth the distance to the axis, arranged in vertical rows down the inner wall of each corallite, project upwards from a broad base ; as many as 20 in a cycle, though full number usually not seen due to silicification. Where common wall between corallites is continuous, spines alternate ; frequently spines appear as discrete units in transverse sections. separated by pores. Tangential sections down a wall show strongly perforate or cribriform appearance, pores being 0-2-0-3 mm in diameter, developed in vertical and horizontal rows; those in vertical rows spaced 10-12 in a length of 5 mm. In oblique sections across corallite walls anastomosing pores are seen with highly irregular outlines. 84 RUSSELL ©: HALL Tabulae very variable in form: complete, horizontal or sagging axially, occasionally arched, rarely incomplete; may be continuous in adjacent corallites, passing through the pores in the walls. Spacing irregular, 7-10 in a length of 5mm. New corallites appear between adjacent corallites. weer ae Sv 8 Thee eye wet are Pied) ‘pee pee PARE A B FiGURE 8.—Calapoecia sp. cf. C. canadensis Billings. (A) UNE F11592/2, L.S., «3-5; (B) samespecimen, L.S.; Xd Remarks : This material agrees very closely with that described as C. canadensis by Cox (1936) except that the tabulae in his description are more closely spaced. The small, vertical tubes which he described as “ disruptive canals” and attributed to the presence of commensal organisms have not been observed in the present material. Hill (1957) noted the first Australian occurrence of this genus from Cudal, N.S.W. Family : Heliolitidae Lindstrom 1876. Subfamily: Plasmoporinae Wentzel 1895 Genus: Plasmoporella Kiaer 1897. Type Species: Plasmoporella convexotabulata forma typica Kiaer 1899. Plasmoporella inflata Hill 1957 Plate IIIc, d 1957 Plasmoporella inflata Hill, p. 104 ; IV, Figures 26a, b; Figures 28a, 0. Material: Two specimens, UNE F11597-8, from which one transverse and one longitudinal section were cut. From Locality 841, lens I, Uralba Beds. Description: Corallum hemispherical with tabularia 1:2—1-6 mm in diameter, with centres between 1-5 and 2-0 mm apart, though some may be in contact. Tabularia circular in cross- section, with 12 short, thick septal ridges projecting into the tabularia, and _ usually extending beyond the wall into the coenenchyme. The septa are connected by curved wall segments, usually unthickened. Plate Tabulae typically complete and gently domed ; spacing variable, usually 16-19 in a length of 5 mm, but where incomplete and highly arched tabellae are developed this number may be as — high as 22. The coenenchyme consists of globose dissepiments of variable size and form ; — new tabularia arise from the coenenchyme. Remarks: The present material is almost § | identical with that described by Hill (1957) and § differs only in having slightly smaller tabularia. § | we I t Plasmoporella sp. cf. P. inflata Hill 1957 Plate IIle, f UNE F11693 and UNE F11729 from Locality — 841, lens I, Uralba Beds. Two transverse and § three longitudinal sections were cut from tice ae material. | 7) Material: Three specimens, UNE F11596, §! i 0 Description : Coralla small, about 3 cm high, with corallites radiating from the base. 9), Tabularia circular in cross-section, ranging from § 1-3 to 1-9 mm in diameter, averaging 1-5 mm ; _ spacing of tabularia in coenenchyme variable, centres from 1-8 to 2-2 mm apart, with adjacent © tabularia sometimes almost in contact. Walls § of tabularia curved, usually thickened (up to 0-15 mm thick), but may be entirely absent, leaving discrete septal ridges around margin of tabularium. Septal apparatus present in the- form of 12 thickened septal ridges (up to 0-2 mm thick) with blunt protrusions extending only about 0-1 mm into the tabularia but up to 0-25 mm into the surrounding coenenchyme. Tabulae horizontal or broadly arched upwards, _ evenly spaced with 20-24 in a length of 5 mm. / Incomplete tabellae, usually more strongly arched, frequently present. Coenenchyme con- + sists of small, arched dissepiments, usually§ ‘« 0-3 to 0-5 mm wide and in approximately/§ horizontal layers between tabularia. Pid\ tar De ye SS, . Remarks: This form shows close similarities} lw with P. inflata Hill in having greatly thickened ti septal ridges which protrude both into the % tabularia and the surrounding coenenchyme ;/§f tty P. inflata has more widely spaced and _ less sin consistently arched tabulae; the tabularia injij i! that species are more evenly distributed through- ys out the coenenchyme and are of slightly smaller} ij diameter. The septal ridges in P. bacilliformis\ wi sp. nov. extend much further into the! coenenchyme and the wall segments are much} thinner; the coenenchymal tissue is more compact and the tabulae more strongly archi HN in that species. 4 Ar UPPER ORDOVICIAN CORAL FAUNAS FROM NORTH-EASTERN N.S.W. Plasmoporella bacillifornis sp. nov. Plate IIIg, h; Figure 9 Name Derivation: Latin bacilliformis=rod- shaped. A reference to the prominent longi- tudinal septal ridges. Material: Four specimens, UNE F11717-9 (holotype UNE F11719) from which five transverse and eight longitudinal sections were cut. Locality 842, Trelawney Beds. Description : Tabularia circular in cross-section, consistently 1-5 to 1-7 mm in diameter and regularly spaced at intervals of 2-0 to 2-5 mm through the coenenchyme. Septa number 12, being thick, blunt ridges which extend 0-2 mm into each tabularium but as much as 0-4 mm _ into the surrounding coenenchyme; wall seg- ments between these thick septal ridges smoothly curved, 0:05 mm thick. Tabulae smoothly arched, complete, closely spaced, 15-20 in a length of 5 mm; incomplete tabellae often present down the margins of tabularia. Coenenchyme consists of small, | arched dissepiments, 0-2—0-4 mm wide and up | to 0-2 mm in height ; some dissepiments broad | and flattened, or sagging in the centre. Ficure 9.—Plasmoporella bacilliformis sp. nov. (A) UNE F11719 (holotype), T.S., x3; (B) UNE F11719 (holotype), L.S., x3. Remarks : This species bears closest resemblance to P. inflata Hill but differs from it in that the septal ridges are thicker and project further beyond the walls of the tabularia into the Surrounding coenenchyme; the coenenchyme of P. bacilliformis is more compact, consisting of smaller, arched dissepiments. The tabulae of the present species are more strongly arched and more closely spaced. Plasmoporella contigua sp. nov. Plate Illi, j; Figure 10 Name Derivation: Latin contiguus=bordering. A reference to the tabularia being in contact. 85 Material: Three specimens, UNE [11720-22, from which two transverse and four longitudinal sections were cut. UNE F11720 designated holotype. From Locality 842, Trelawney Beds. Description: Corallum 9-5 cm across, with corallites radiating from the base. Tabularia of constant size, 1:2 to 1-4 mm in diameter, with walls 0-06—-0-1 mm thick. Where corallites in contact, cross-sectional form is polygonal, becom- ing circular only where coenenchyme present. Septal apparatus consists of continuous ridges which in transverse section vary in appearance from sharp, spine-like protrusions up to 0:2 mm long to blunt, rounded protrusions. Number of FiGcureE 10.—Plasmoporella contigua sp. nov. (A) UNE F11720/1 (holotype), T.S., x3; (B) UNE F11720/2 (holotype), L.S., x3. ridges seen in each corallite varies, commonly 11, maximum 12. Tabulae strongly arched upwards, evenly spaced with 13 to 16 in a length of 5mm ; incomplete and strongly arched tabellae present. Small, irregular patches of coenenchyme occur between many corallites, being 0-2 to 0:7 mm across and containing small, arched dissepiments. Remarks : P. contigua is apparently unique for this genus in having coenenchyme only irregularly developed, with walls of most tabularia in contact. This produces a very close resemblance to Proheliolites Kiaer in transverse sections, but the vertical series of downwardly directed septal spines so character- istic of that genus are lacking. The horizontal elements of the coenenchyme are _ globose dissepiments rather than horizontal solae as in Proheliolites. Genus : Plasmopora Milne-Edwards and Haime 1849. Type Species : 1839. Porites petalliformis Lonsdale 86 Plasmopora circumflexa sp. nov. Plate IIIk, 1 Name Derivation: Latin circumflexus=arched. A reference to the form of the tabulae. Material: One specimen, UNE F11694, from Locality 841, lens A, Uralba Beds; and four specimens, UNE F11723-6, from Locality 842, Trelawney Beds. UNE F11723 designated holotype. Description : Tabularia circular in cross-section, ranging between 0-8 and 1-2 mm in diameter ; distance between centres of adjacent tabularia from 1-1 to 3-0 mm (mostly 1-3-1-6 mm) ; tabularia separated by one to four rows of tubules which are between 0-15 and 0:3 mm across. Twelve tubules’ surround’ each tabularium, their walls usually being continuous with the septa; in some instances narrow extensions from surrounding tubules may reach the tubularium walls. Tubules immediately surrounding tabularia do not differ in size or form from those in the remainder of the reticulum. Walls of tabularia circular in cross- section, rarely crenulate ; not thickened relative to walls of tubules; spines blunt and of even thickness, ranging up to 0-24 mm in length, 12 in each tabularium. Tabulae smoothly arched, evenly spaced ; usually 14-16 in a length of 5 mm, though this number may vary between 10 and 20. Occasionally tabulae may be flat or sagging where they are more unevenly spaced; some incomplete tabellae. Coenenchyme consists of slender tubules, polygonal in cross-section, with horizontal solae which are spaced 20 to 30 ina jength of 5 mm. Remarks : This species is characterized by the constantly arched tabulae and well developed septal spines. Genus: Cyrtophyllum Lindstrom 1882. Type Species: Cyrtophyllum densum Lindstrom 1882. Cyrtophyllum sp. Plate IVa, b Material : One transverse and one longitudinal section cut from material no longer extant, UNE F11695. From Locality 841, lens I, Uralba Beds. Description: Tabularia of even size, ranging from 0-7 to 1-0 mm in diameter, circular in cross-section, with strongly crenulate walls. Distances between the centres of adjacent tabularia vary between 1:0 and 1-5 mm; commonly separated by one, though occasionally RUSSELL -L, HALE as many as three, rows of tubules. Walls of tabularia slightly thickened relative to those of tubules, being from 0-04 to 0-1 mm thick. — Twelve septa, ranging in form from blunt, — rounded protrusions of the crenulated walls to § definite ridges projecting up to 0-1 mm into the © tabularium. Tubules rounded to subangular in cross- | section, usually 0-2—0-3 mm in width and often ~ with discontinuous walls. Tabulae smoothly concave upwards and evenly spaced with 20-25 — in a length of 5 mm; pairs of tabellae are common, being inclined towards axis to rest on — tabulum next below. Solae horizontal, closely spaced, 40-45 in a length of 5 mm, sometimes continuous across several tubules. depressed and closely spaced tabulae, with frequent incomplete tabellae. section is characterized by frequent dis- continuities in the tubule walls. Family: Favositinae Dana 1846 Genus : Palaeofavosites Twenhofel 1914. Type Species : Favosites aspera d’Orbigny 1850. Favosites on the basis of having mural pores — 7 Discussion : Palaeofavosites was separated from j - i largely or completely confined to the wall | angles or corallites ; septal spines may or may | not be Flower (1961) regarded ~ the present. genus Foerstephyllum as and numerous septal ridges or rows of septal 9 spines, commonly 20 or more in number, some © In advanced species the fibrous 7 sclerenchyme of the common walls between | ; . in two series. adjacent corallites becomes separated by a thin, | Mural pores are lacking | in the older species but occur in younger species. | Flower (1961) described as Palaeofavosites dark “axial plate’’. sparsus a form with wall structures and tabulae lacking septal spines ; mural pores were present — in the wall angles. sessing mural pores but with the septal apparatus © represented by a series of spines were placed by © i / resembling those of Foerstephyllum vacuum, but } : p. 70 and F. porosum, p. 71), though he recog-— nized the transitional nature of these forms. | It seems preferable to retain in the genus Palaeofavosites all those forms possessing mural 7 pores in the wall corners, rather than posing the | difficulty of distinguishing members of this © genus from species of Foerstephyllum on the | basis of combinations of such variable characters © as the degree of development of spines or septal — ridges and microstructure of the walls. Flower in the genus Foerstephyllum (F.nuinutum, i ) | Remarks: This form is characterized by | The transverse iJ | ! : 5 } including © Ordovician cerioid corals with fairly thick walls 9 UPPER ORDOVICIAN CORAL FAUNAS FROM NORTH-EASTERN N.S.W. 87 Palaeofavosites magnus sp. nov. Plate [Vc, d. Name Derivation: Latin magnus=large. A reference to the many corallites of unusually large diameter. Material: A _ single corallum, UNE F11728 (holotype), from Locality 841, Uralba Beds, from which four transverse and_ three longitudinal sections were cut. Four specimens, UNE F11713-6, from Locality 842, Trelawney Beds; from this material two transverse and five longitudinal sections were cut. Description : Corallum massive, cerioid, corallites radiating from the base; polygonal in cross-section, reaching 4-6 mm in diameter, but averaging between 2-0-3:0 mm. Wall segments typically curved, but may be straight or wavy; 0-05 to 0:15 mm thick, with a distinct dark, axial plane bounded by sclerenchyme. Tabulae thin, complete, gently sagging or domed in centres, with edges turned up or down ; spaced evenly, 5-9 in a length of 5 mm. Pores averaging 0-1 mm in diameter observed very close to wall angles. Remarks : P. sparsus Flower and P. mccullochae Flower from North America have the same average dimensions as the present species, but lack the large diameter corallites. Both these species have tabulae rather more widely spaced. Palaeofavosites crassus sp. nov. Plate IVe, f Name Derivation: Latin crassus=thick. A reference to the very thick walls in some parts of the corallum. Material: A single corallum (the holotype), UNE F11599, from which two transverse and two longitudinal sections were cut. From / Locality 841, lens I, Uralba Beds. Description: Corallum massive, cerioid ; corallites polygonal, varying in diameter between 1-8 and 3-8 mm. Wall segments straight or wavy, of variable thickness with a dark axial plane. In those parts of corallum where walls thickened (up to 0-2 mm), 16-20 thick, blunt septal ridges are observed which in adjacent corallites may be opposite or alternate to give the walls a strongly crenulate appearance in cross-section. Where corallite walls are thin (0-02-0-1 mm) the septal ridges are narrow and pointed. Two series of septa not observed. Tabulae straight and complete, or wavy with edges turned up or down; evenly spaced with 6-10 in a length of 5mm. Mural pores clearly seen in transverse and longitudinal sections very close to the wall angles. Remarks : This species is characterized by the continuous, vertical septal ridges, especially in those parts of the corallum where the walls are thickened. The thin, dark axial plane is frequently obscured in such zones. The septal ridges appear as continuous vertical elements in longitudinal sections passing close to the corallite wall, suggesting that their distal edges are smooth rather than serrated as in P. spinimarginatus. The mural pores are found in vertical rows down either side of the wall angle, being round, 0-1 mm in diameter and about 0-4 mm apart. Palaeofavosites spinimarginatus sp. nov. Plate IVg, h; Figure 11 Name Derivation: Latin spina=spiny ; Latin marginatus=margined. A reference to the spines on the inner edges of the septal ridges. Material: A single specimen, UNE F11727 (holotype), from which one transverse and one longitudinal section were cut. From Locality 842, Trelawney Beds. Description: Corallum massive, corallites polygonal, five to seven, but usually six-sided ; mature corallites range in diameter from 1-7 to A B FicurRE 11.—Palaeofavosites spinimarginatus sp. nov. (A) UNE F11727/1 (holotype), T-S., X2-°5; (B) UNE F11727/2 (holotype), L.S., x 2-5. 2-2 mm. Walls straight with a dark axial plane always present, 0-05—0-1 mm thick, with very short, sharp spines up to 0-1 mm in length. Spines number up to 18 in a cycle, but usually fewer than this observed in one section. Septal 88 RUSSEEL L. HALL apparatus consists of lamellar ridges which are produced into short, sharp spines along their inner edge; in oblique longitudinal sections they appear as continuous vertical lines which break up into a series of dots as they pass out of the plane of section. Tabulae horizontal, gently sagging or wavy, with edges usually turned up or down approach- ing wall; evenly spaced, with 8-14 in a length of 5mm. Mural pores located at wall corners, 0-05-0-1 mm in diameter. Remarks : Comparison of the septal apparatus in the present material with that in P. crassus and P. rarispinulatus suggests that the present species is transitional, having continuous lamellar septal ridges which break up into discrete spines along their inner edge. This species has generally smaller corallite diameters than the other species of the genus described in this paper, lacks wall thickening and has more closely spaced tabulae. Palaeofavosites rarispinulatus sp. nov. Plate IVi, j Name Derivation : Latin spinula=small thorn ; Latin varus=scarce. A_ reference to the infrequent small spines. Material: Nine specimens, UNE F11601-9, from Locality 841, lens I, Uralba Beds. Five transverse and five longitudinal sections were prepared. Holotype is UNE F11608. Description : Corallum massive, cerioid ; corallites polygonal, varying in diameter between 1-3 and 3-8 mm, most in the range 1-9-2-6 mm. Wall segments may be straight, wavy or curved in transverse section, varying in_ thickness between 0-05 and 0-2 mm, with a thin, dark axial plane. Septal spines usually present, but variable in development with 2-16 in any one corallite, arising from wall crenulations where these are present; spines short and pointed. Mural pores occasionally seen, very close to wall corners. Tabulae evenly spaced, 6-8 in a length of 5 mm; complete, horizontal or wavy, with edges turned up or down near walls; in some corallites tabulae extremely variable in form and spacing becomes irregular. Remarks : P. rarispinulatus differs most notice- ably from P. crassus in having the septal elements reduced to discrete spines ; a maximum of 16 spines has been counted in one corallite but in most only a few are seen, suggesting that they are widely spaced in vertical rows. Palaeofavosites sp. Plate IVk, | Material: A single specimen, UNE F11600, — from which two transverse and three longitudinal |} ° sections were cut. From Locality 841, lens I, |}? Uralba Beds. Description : Corallites polygonal, four to seven — sided, with very thick walls (0-1-0-4 mm) which are often crenulate in both transverse and longitudinal sections, with a dark axial plane. © Corallites large, from 3-0 to 4-1 mm in diameter. © Septa or septal spines lacking. Round mural > pores, 0:15-0:24 mm in diameter, located in — wall corners, but rare. Tabulae evenly spaced, 7-8 in a length of 5 mm, usually wavy with edges turned up or down near walls. In transverse sections many small, curved lines adjacent to the walls indicate the crenulate nature of the edges of the tabulae. — Remarks : This species is characterized by the — large corallites with thick walls, lacking septa, and particularly by the crenulate tabulae. Family: Auloporidae Milne-Edwards Haime 1851. Subfamily : Syringoporinae Nicholson 1879. Genus: Reuschia Kiaer 1930. Type Species : Reuschia aperta Kiaer 1930. and Reuschia sp. Plate Va Material : Part of a single colony from Locality — 842, Trelawney Beds, from which one thin section was cut, UNE F11743. Description : Corallum phaceloid, with corallites in contact for 2-3 mm after branching, often — forming cerioid patches; corallites branch outwards from axis of colony and are not parallel. Corallites circular in cross-section, 1:5-2:5 mm > in diameter, averaging 2:3 mm, with thick walls and a very narrow lumen. Typical corallite of 2-2 mm diameter having a central lumen of 0-5 mm in diameter surrounded by a thick wall (0-85 mm) consisting of two distinct layers. The outer layer, 0:25 mm thick, separated from the thick (0-6 mm) inner layer by a dark line. Inner surface of wall may have occasional broad undulations. In longitudinal sections tabulae not seen; calyx expanded. Remarks: Kaljo and Klaaman (1965) list occurrences of this genus from the Upper Ordo- vician of Norway (Hill, 1953) and China (Yu, 1960) ; Hill (1959) also describes a species from Arizona, R. subparallelus. The present form is similar to this last species in general dimensions but differs in having corallites that diverge from the central axis of the colony. Family : Halysitidae Milne-Edwards and Haime 1850. Subfamily : Haime 1850. Genus: Halysites Fischer von Waldheim 1813. Type Species: Tubipora catenularia Linnaeus 1767. Halysitinae Milne-Edwards and Halysites sp. Plate Vb, c; Figure 12 Material: A single specimen, UNE F11752, from Locality 841, lens K, Uralba Beds. Two transverse and two longitudinal sections were prepared. _ Description : Corallum of slender corallites, up to 9 cm tall ; ranks of one to five, usually three, macrocorallites bounding compact lacunae of A B Figure 12.—Halysites sp. (A) UNE F11752/1, T.S., x5; (B) UNE F11752/2, L.S., x65. | polygonal or somewhat elongated cross-sectional form, eg. 3:0x6:0 mm; 4:0x7-:0 mm; my) 2-2x10-3mm; 5-5x2-0mm. Macrocorallites al}) oval in cross-section, averaging 1-4-1-7 mmx ell] 0-8-1-0 mm in size, with smoothly convex walls 1) 0-1-0-13 mm thick. Septal spines absent. iil}} Walls constricted between macrocorallites ; ratio fo} Lonay e 5 @ ~s oO te wn ro) = 7) =] Qu i) =) a 3. =| oO i=} a 5 Li | (=) 77) ct (o} | 77) Rectangular microcorallites, averaging 0-2 x }0-6 mm in size and with their greater length | transverse to the rank, occupy the constrictions | between macrocorallites. Mesocorallites at the junction of ranks are triangular to polygonal in del] cross-section and about 0:5 mm across. (\} Tabulae in the macrocorallites are straight, otf} horizontal and evenly spaced with 9-12 in a mijlength of 5 mm; those in microcorallites are sit} More closely spaced. yet ih UPPER ORDOVICIAN CORAL FAUNAS FROM NORTH-EASTERN N.S.W. 89 Remarks : The single specimen of this species is silicified and has been compressed so that accurate measurements of corallite diameters proved difficult to obtain. Webby and Semeniuk (1969) have described the only true Halysites previously known from Ordovician rocks: H. praecedens from the upper parts of the Bowan Park Limestone and the Canomodine Limestone in the central west of New South Wales. These strata have been correlated with the Upper Eastonian. The present form differs noticeably from H. praecedens in having compact lacunae with frequent junctions between ranks which contain only a few macrocorallites ; no lacunae are known in the material representing H. praecedens which has long, open ranks of corallites. The specimen from the Uralba Beds has more elongated macrocorallites, with less marked constrictions in the walls and narrower microcorallites in comparison with H. praecedens. Subfamily : Cateniporinae Hamada 1957. Genus : Catenipora Lamarck 1816. Type Species: Catentpora escharoides Lamarck 1816. Catentpora flexa sp. nov. Plate Vd-g Name Derivation: Latin flexus=bending. A reference to the form of the ranks. Material: Eleven specimens, often silicified, UNE F11644-54, from which nine transverse and eleven longitudinal sections were cut ; UNE F11650 designated holotype. From Locality 841, lenses B and I, Uralba Beds. Description: Lacunae variable within each colony, ranging from medium, oval in cross- section (1-0 x0-5 cm) formed by ranks contain- ing 4-6 corallites, to curved, labyrinthine (5:0x1-0 cm) with ranks containing 2-13 corallites. Macrocorallites oval in cross-section with thin, dark holotheca ; average size 1-8 x 1-3 mm, with walls smoothly convex, giving a ratio of 2: 3 for the width at constrictions and corallite midlengths respectively. In cross- section chambers vary from oval with smoothly rounded ends to subquadrate with ends flattened along common wall between corallites. Micro- corallites absent ; mesocorallites absent. Walls range in thickness between 0-2 and 0-4 mm; in corallites where greatest wall thickness is developed three distinct wall layers (holotheca, midwall and peripheral stereozone) are seen. Spines are developed in well-defined vertical rows, with as many as ten rows in each corallite ; development of spines down length 90 RUSSELL [HALL of any corallite apparently not continuous, many chambers showing from two to four horizontal rows between adjacent tabulae, with none in adjacent chambers. Spines thick at base, projecting upwards and usually pointed ; deposits of poikiloplasm frequently obscure or completely replace spines. Tabulae complete, horizontal, gently arched or sagging; spacing uneven down length of each corallite ranging from 7 to 10 in a length of 5 mm. Remarks: This species closely resembles C. workmanae Flower (1961) from the Second Value Formation, New Mexico but differs in having larger, more open lacunae bounded by curved ranks of corallites. Australian representatives of this genus are known from a limestone breccia at the top of the Malachi’s Hill Beds (Webby and Semeniuk, 1969, p. 357) and the upper beds of the Gordon Limestone of Tasmania (Etheridge, 1900; Banks, 1962). C. flexa is readily dis- tinguished by the ranks of uniform, oval corallites forming elongated, labyrinthine lacunae and the frequent development of spines. Catentpora spatiosa sp. nov. Plate Vh, i; Figure 13 Name Derivation: Latin spatiosus=roomy. A reference to the wide spacing of the ranks. Material: Five specimens, UNE F11639-4 ; UNE F11640 designated holotype. Three trans- verse and two longitudinal sections were cut from this material, from Locality 841, lens A, Uralba Beds. A B FIGURE 13.—Catenipora spatiosasp. nov. (A) UNE F11640/2 (holotype), T.S., «3-5; (B) UNE F11640/1 (holotype), L.S., «3-5. Description: Lacunae large, elongated, often labyrinthine, up to 1-0 cm wide and often exceeding 3-5 cm in length. Walls 0-3 mm thick, with thin, dark holotheca and in places a third layer can be seen in the wall structure. Macrocorallites large, ranging from 1-6 to 2-6 mm in length and 1-5 to 1-8 mm in width ; end of chambers flattened, with thin, straight walls between adjacent corallites. External walls only slightly convex, giving a ratio for the diameters at the end and midlength of corallites respectively of 7:8. Septa only occasionally seen in transverse §- sections as short spines up to 0-1 mm long; in 9, tangential longitudinal sections the cut ends of j : these spines are seen in vertical rows, with three /§ , 3 ililieieetenietahdieteiddidesiet ke or four horizontal rows between adjacent tabulae. © Tabulae thin, complete, horizontal or slightly © sagging; evenly spaced with 6-8 in length of 5 mm. 1 Remarks : This species resembles Falsicatentpora chillagoensis (Etheridge) but definitely lacks | mesopores at the junctions of ranks. In his |§ original description Etheridge makes no mention |} of gonopores (—mesopores) but refers to “ feeble | gonopores’’ in material from the Gordon) Limestone in Tasmania which he believed to be © conspecific with the material from Chillagoe, Queensland. Genus: Quepora Sinclair 1955. Type Species: Halysites catenularia va Quebecensis Lambe 1900. Quepora sp. Plate V j-l i" Maternal: Your specimens, UNE F11739-42)99 g; from which four transverse and four longitudinal} py sections were cut. From Locality 841, lens K,¥ jj, Uralba Beds. Remarks: The material representing this form has been deformed and only broken fragment of the ranks have been preserved ; no lacuna have been seen. However, the material rep resents an undoubted Quepora. Corallites an rounded to slightly oval in cross-section ; the? longer diameter ranges from 1-3 to 1-6 mm, the shorter diameter from 0-7 to 1-1 mm. Septal} spines absent ; microcorallites and mesocorallite absent. Tabulae horizontal, straight and eve spaced, 6-8 in a length of 5 mm. Subfamily : Schedohalysitinae Hamada 1957 Genus : Falsicatentpora Hamada 1958. Type Species: Halysites japonicus Sugiyami 1940. Falsicatentpora stricta sp. nov. Plate Vm, n; Figure 14 Name Derivation: Latin strictus=straight. reference to the straight walls of the macré corallites. . Material: Four specimens, silicified, UNE F11734—7 ; UNE F11734 designated holotype. From Locality 841, lens F, Uralba Beds. Description : Corallum tall, up to 9-0 cm high ; corallites radiating from the base to form | hemispherical surface. Lacunae compact, with §| smooth outlines, polygonal or elongated in cross-section; sizes 7°5xX2-5 mm; 3:2~x 2-2 mm; 3:-5x1-5 mm. Ranks moniliform, consisting of one or two macrocorallites which are elongated parallel to the rank, narrow, with straight walls (0-08-0-1 mm thick) which are ¢ A B FicuURE 14.—Falsicatenipora stricta sp. nov. (A) UNE F11734/1 (holotype), T.S., 3-5; (B) UNE F11734/2 (holotype), L.S., 3-6. not constricted at corallite junctions. Macro- corallites 1-1 0-5 mm, 1:-4x0-4 mm. Septal spines alsent. Microcorallites entirely absent ; lj) mesocorallites occasionally present at junction l§) of ranks, triangular to rounded in cross-section with internal diameter of 0:02 mm. Tabulae in am; macrocorallites thin, straight, evenly spaced jwith 17-25 in a length of 5 mm. | Remarks: This species is easily recognized in @jhand specimen by the long narrow macro- ®\corallites with straight sides which lack septal @ispines. The compact, polygonal and smooth- jpeed lacunae give this species a superficial Mitresemblance to Halysites lithostrotonoides @) Etheridge, but the shape of the macrocorallites jis again distinctive. The rectangular form of the macrocorallites is similar to those of F. hillae (Hamada) but in the present species they are more elongated and the lacunae are larger. Acknowledgements I wish to express my gratitude to Professor . M- Philip who encouraged the beginning of his study and who made available for descrip- ion material he collected from the Trelawney , geds. Dr. B. Runnegar, Professor Dorothy Hill mm d Dr. B. Webby provided valuable advice F d discussion on taxonomic and_ bio- ' UPPER ORDOVICIAN CORAL FAUNAS FROM NORTH-EASTERN N.S.W. 91 stratigraphic considerations, literature and preparation of the manuscript for publication. Assistance in preparing the illustrations was given by Mr. B. Whan, Mr. J. Whorwood and Dr. D. Ellenor. References Banks, M. R., 1962. Ordovician System. The Geology of Tasmania. J. geol. Soc. Aust., 9, 147. BassLer, R. S., 1915. Bibliographic Index of American Ordovician and Silurian Fossils. U.S. Nat. Mus. Buill., 92. BassLer, R. S., 1950. Faunal Lists and Descriptions of Palaeozoic Corals. Mem. geol. Soc. Am., 44. BILuincs, E., 1858. Report for the year 1857. Rep. geol. Surv. Can., for 1857, 142. Bitiincs, E., 1865. Notice of Some New Genera and Species of Palaeozoic Fossils. Canadian Naturalist, new ser., 2, 425. BrowneE, R. G., 1965. Some Ordovician Colonial Corals of North-Central Kentucky. /. Paleont., 39, 1177. CHAPPELL, B. W., 1961. The Stratigraphy and Structural Geology of the Manilla-Moore Creek District, N.S.W. J. Proc. R. Soc. N.S.W., 95, 63. Cox, I., 1936. Revision of the Genus Calapoecia Billings. Canada nat. Mus. Buil., 80, 1. Crook, K. A. W., 1961. Stratigraphy of the Tamworth Group (Lower and Middle Devonian), Tamworth- Nundle District, N.S.W. J. Proc. R. Soc. N.S.W., 94, 173. DysowskI, W.N., 1873. Monographie der Zoantharia sclerodermata rugosa aus der silurformation Estlands, Nord-Livlands und der Insel Gotland. ETHERIDGE, R., 1900. A Tasmanian Species of Halysites. Pap. Proc. R. Soc. Tasm. for 1898-99. ETHERIDGE, R., 1918. Two Remarkable Corals from the Devonian of New South Wales. Rec. Aust. Mus., 12, 49. FLoweEr, R. H., 1961. Colonial Corals. Mex., 7, 1. Hatt, R. L., 1963. Geology of an Area North-east of Attunga, New South Wales. Univ. New England, B.Sc. Hons. Thesis (unpubl.). Hitt, D., 1953. The Middle Ordovician of the Oslo Region, Norway. 2. Some Rugose and Tabulate Part I. Montoya and Related Mem. Inst. Min. Technol. New Corals. Norsk. Geol. Tidssky., 31, 143. Hitt, D., 1957. Ordovician Corals from New South Wales. J. Proc. R. Soc. N.S.W., 91, 97. Hitt, D., 1959. Mexico, Arizona and Texas. Technol. New Mex., 64, 1. Hirt, D., 1961. On the Ordovician Corals Palaeo- phyllum rugosum Billings and Nyctopora billingsiz Nicholson. Bull. geol. Surv. Can., 80, 1. Jounston, D. A., 1968. The Geology of the Halls Creek-Oaky Creek District, South of Bingara, N.S.W. Univ. New England, B.Sc. Hons. Thesis (unpubi.). Kayo, D., and Kraaman, E., 1965. The Faunas of the Portrane Limestone, III The Corals. - Bull. Br. Mus. nat. Hist., Geology, 10, 422. K1AER, J., 1899. Den Korallenfaunen der Etage 5 des norwegischen Silursystems. Palaeontographica, XLVI, 1. Some Ordovician Corals from New Bull. Inst. Min. 92 KIakER, J., 1930. Den fossilforende ordovicisk-siluriske lagrekke pa Stord og bemerkninger om de ovrige fossilfun i Bergens feltet. Bervgens Mus. Arbok. Naturv. vekke, Il, 1. LaMBE, L. M., 1901. A Revision of the Genera and Species of Canadian Palaeozoic Corals. The Madreporaria Aporosa and the Madreporaria Rugosa. Geol. Surv. Canada, Contrib. Canadian Palaecont., IV, 97. Linnaeus, C., 1767. Systema Naturae I: and (37). Edito Duodecima Reformata. LoNSDALE, W., 1839. See Murchison, R. I. Murcuison, R. I. The Silurian System. Pts. I, II, 657. D’ORBIGNY, A., 1850. Prodrome de Palaeontologie. PackHAM, G. H., 1969. The Geology of New South 533-1327 Wales. J. geol. Soc. Aust., 16 (1). Pestana, H. R., 1960. Fossils from the Johnson Springs Formation, Middle Ordovician, Inde- pendence Quadrangle, California. J. Paleont., 34, 862. Puitip, G. M., 1966. The Occurrence and Palaeo- geographic Significance of Ordovician Strata in Northern New South Wales. Aust. J. Sci., 29, 112. PicKEtTT, J., 1966. Lower Carboniferous Coral Faunas from the New England District of New South Wales. Mem. geol. Surv. N.S.W. Palaeontology, NE University of New England, Armidale, N.S.W. Present address : McMaster University, Hamilton, Ontario, Canada. (Received 30.9.74) EXPLANATION OF PLATE 1 FIGURES a-e.—Palaeophyllum sp. cf. P. rugosum Billings. fused in small groups and weakly developed minor septa ; (b) and (c) UNE F11570, T.S., x3; (d) UNE F11555/6 L.S., x4; (e) UNE F11555/3, L.S., x4. Ficures f-j.—Palaeophyllum bothroides sp. nov. (f) UNE F11573/1 (paratype 1), T.S., x4; (g) and (hy UNE F11573/1, T.S., x2; (i) UNE F11575/4 (holotype), L.S., x3, showing deep trench-like structure in tabulae (j) UNE F11575/3 (holotype), L.S., x3. Figures k-n.—Palaeophyllum sp. cf. P. thomi (Hall). respectively, L.S., x5; (1) UNE F11586/2, T.S., x6; (n) UNE F11588/3, T.S., x3. FicuRESs 0-q.—Palaeophyllum trelawneyense sp. nov. (0) enlargement of part of (p), T.S., x6; (p) UN F11744/1 (holotype), T.S., x2; (q) UNE F11744/8 (holotype), L.S., x4. EXPLANATION OF PLATE II Figures a, b.—Cyathophylloides sinuata sp. nov. (a) UNE F11698/1 (holotype), T.S., x3; (b) UNE F11698/ (holotype), L.S., x3. FicuREs c, d.—Cyathophylloides juncta sp. nov. (c) UNE F11701/2 (holotype), (holotype), L.S., x6. FiGuRES e, f—Crenulites australis sp. nov. (e) UNE F11705/1 (holotype), T.S., x4; Note amplexoid septa and crenulated margins of tabulae. g, h.—Crenulites australis minor sp. et subsp. nov. (g) UNE F11712/1 (holotype), T.S., x# (paratype 2), L.S., x4. FIGURES (h) UNE F11712/2 (holotype), L.S., x4. FicureEs i-l.—Indeterminate streptelasmatids. RUSSEEL LS HALE (i) and (1) UNE F11687, L.S., x2 and UNE F11689, T.S x 1-5, respectively ; (j) UNE F11688, T.S., x1-5; (k) UNE F11738, T.S., x1-5. oe er err ee en oe RUNNEGAR, B. N., 1970. The Permian Faunas of Northern New South Wales and the Connection Between the Sydney and Bowen Basins. J. geol. Soc. Aust., 16, 697. SIMMONS, G. C., and OLIVER, W. A., 1967. Otter Creek Coral Bed and its Fauna, East-Central Kentucky. Bull. U.S. geol. Suvv., 1244F. SPJELDNAES, N., 1964. Two Compound Corals from the Tretaspis Beds of the Oslo-Asher District. Institutt. for Geologi, avd. C. Blindern. Strusz, D. L., 1961. Lower Palaeozoic Corals from New South Wales. Palaeontology, 4, 334. Suciyama, T., 1940. Stratigraphical and Palaeonto- logical Studies of the Gotlandian Deposits of the Kitakami Mountainland. Sci. Rep. Tohoku Univ., ser. 2, Geology, 21. VoisEy, A. H., 1959. Tectonic Evolution of North- Eastern New South Wales, Australia. J. Proc. R. Soc. N.S.W., 92, 191. Wessy, B. D., 1969. Ordovician Stromatoporoids from New South Wales. Palaeontology, 12, 637 Wespy, B. D., 1972. The Rugose Coral Palaeophyliu Billings from the Ordovician of Central New South Wales. Proc. Linn. Soc. N.S.W., 97, 150. WesBY, B. D., and SEMENIUK, V., 1969. Ordovician Halysitid Corals from New South Wales. Lethaia, 2, 345. Yu, Cu., 1960. Pozdneordovikskije korally Kitaja Acta palaeont. sin, 8, 65. (a) UNE F11560, T.S., x6, showing major septz (k) and (m) UNE F11590/1 and UNE F11791/ T.S., x6; (d) UNE F11701/ - (f) UNE F11706/5 TALI. PEATE N.S.W. r WErSOCIETY OURNAL ROY ‘3 iT MN Shindhs: JOURNAL ROYAL SOCIETY N.S.W. HALL PIATE. es wee i Pen NY NY NY Q MM x n) Q nN) ny) a q N.S.W. be f « / gi K a AL SOCIETY e. bal e JOURNAL ROY Ss = Sa] <= = ) Q NX wy) X a Los N ns JOURNAL ROYAL SOCIETY PEATE i L HA > nH N. r SOCIETY JOURNAL ROYAL UPPER ORDOVICIAN CORAL FAUNAS FROM NORTH-EASTERN N.S.W. 93 EXPLANATION OF PLATE III FicurEs a, b.—Calapoecia sp. cf. C. canadensis Billings. (a) UNE F11592/1, T.S., x4; (b) UNE F11592/2, L.S., x4. Showing spinose septa and cribriform wall structure. Ficures c, d.—Plasmoporella inflata Hill. (c) UNE F11598/2, T.S., x4, showing septal spines extending into coenenchyme; (d) UNE F11598/1, L.S., x4, showing arched tabulae. Ficures e, f.—Plasmoporella sp. cf. P. inflata Hill. (e) UNE F11693/3, T.S., x4, showing thickened septal ridges and in places absence of wall; (f) UNE F11729/1, L.S., x4. Figures g, h.—Plasmoporella bacilliformis sp. nov. (g) UNE FI11718/l, paratype 2, T.S., x4, showing thickened septal ridges and absence of corallite walls ; (h) UNE F11719/2 (holotype), L.S., x4, showing thick, continuous septal ridges and strongly arched tabulae. Figures i, j.—Plasmoporella contigua sp. nov. (i) UNE F11720/1 (holotype), T.S., x4, showing septal ridges and small patches of coenenchyme developed at corners of adjacent corallites ; (j) UNE F11720/2 (holotype), Ls., x4. Figures k, 1.—Plasmopora cirvcumflexa sp.nov. (k) UNE F11723/1 (holotype), T.S., x4; (1) UNE F11724/1 (paratype 1), L.S., x4. EXPLANATION OF PLATE IV FiGurEs a, b.—Cyrtophyllum sp. (a) UNE F11659/1, T.S., x4, showing tubules with discontinuous walls ; (b) UNE F11695/2, L.S., x4. Ficures, c. d.—Palaeofavosites magnus sp.nov. (c) UNE F11728/1 (holotype), T.S., x4; (d) UNE F11728/2 (holotype), L.S., x4. Ficures e, f.—Palaeofavosites crassus sp. nov. (e) UNE F11599/2 (holotype), T.S., x4, showing thickened walls with dark axial line, pores in wall angles; (f) UNE F11599/3 (holotype), L.S., x4, showing pores near wall angles and continuous septal ridges. Ficures g, h.—Palaeofavosites spinimarginatus sp. nov. (g) UNE F11727/1 (holotype), T.S., x4; (h) UNE F11727/2 (holotype), L.S., x4, showing cut ends of spines grading into continuous septal ridge. FicuREs i, j.—Palaeofavosites vavispinulatus sp. nov. (i) UNE F11608/1 (holotype), T.S., x4, showing rare septal spines and pores in wall angles; (j) UNE F11603/3 (holotype), L.S., x4. Ficures k, 1.—Palaeofavosites sp. (k) UNE F11600/2, T.S., x4; (1) UNE F11600/4, L.S., x4. EXPLANATION TO PLATE V FIGURE a.—Reuschia sp. UNE F11743, tangential section through colony, 1-5, showing thick walls and narrow central lumen. Ficures b, c.—Halysites sp. (b) UNE F11752/1, T.S., x4, showing form of ranks and lacunae, with micro- corallites visible in bottom centre; (c) UNE F11752/2, L.S., x4. Ficures d—g.—Catenipora flexa sp. nov. (d) UNE F11650/2 (holotype), T.S., 2, showing curving ranks of macrocorallites with spines ; (e) enlargement of part of Figure (d) showing septal spines, x5; (f) UNE F11650/10 (holotype), L.S., x8, showing ends of septal spines; (g) UNE F11650/7 (holotype), L.S., x6, showing vertical rows of septal spines. Ficures h, i—Catenipora spatiosa sp. nov. (h) UNE F11640/2 (holotype), T.S., x2, general view showing large macrocorallites ; (i) UNE F11640/1 (holotype), L.S., x5. =. Figures j-l.—Quepora sp. (j) UNE F11740, T.S., x4; (k) UNE F11742, T.S., x4; (l) UNE F11742, i. <5. FicurEs m, n.—Falsicatenipora stricta sp. nov. (m) UNE F11734/1 (holotype), T.S., x6, showing compact lacunae and macrocorallites with straight sides; (n) UNE F11734/2 (holotype), L.S., x6. AUSTRALASIAN MEDICAL PUBLISHING CO. LTD. 71-79 ARUNDEL ST., GLEBE, N.S.W., 2037 975 | : E THE ROYAL SOCIETY OF NEW SOUTH WALES The Society originated in the year 1821 as the Philosophical Society of Australasia. Its main function is the promotion of Science through the following activities : Publication of results of scientific investigation through its Journal and Proceedings; the Library ; awards of Prizes, and Medals ; liaison with other Scientific Societies ; Monthly Meetings ; and Summer Schools for Senior Secondary School Students. Special Meetings are held for the Pollock Memorial Lecture in Physics and Mathematics, the Liversidge Research Lecture in Chemistry and the Clarke Memorial Lecture in Geology. 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The Society welcomes manuscripts of research (and occasional review articles) in all branches of science, art literature and philosophy, for publication in the Journal and Proceedings. Manuscripts will be accepted from both members and non-members, though those from the latter should be communicated through a member. A copy of the Guide to Authors is obtain- able on request and manuscripts may be addressed to the Honorary Secretary (Editorial) at the above address. Contents Astronomy : Occultations Observed at Sydney Observatory 1973. K. P. Sims Earth Rotation Related to Net Electric Charge—Communication to Editor— I. Michelson : - 3 Biochemistry : Potential Antitumour Activity of Some Amino Acid Metal Systems. A. J. Charlson, Kevin E. Trainor and Edward C. Watton Geology : Bedrock Topography in Northern Jervis Bay, B.D. Johnson and A. D, Albam Structure and Jointing in Permian Rocks Near Ravensworth, New South Wales, Northern Sydney Basin. D. R. Gray The Geology of the Windellama Area, N.S.W., Ruth Mawson oe The Merrimbula Group of the Eden-Merrimbula Area, N.S.W. J. Steiner Mathematics : Local Compactness and Free Products of Topological Groups. S. A. Morris Palaeontology : Lower Silurian Rugose Corals from Central New South Wales. R.A. McLean Note on Fossil Megafloras of the Nymboida and Redcliff Measures, Southern Clarence Morton Basin, N.S.W. J. E. Flint and R. E. Gould Upper Ordovician Coral Faunas from North-Eastern New South Wales. R. L. Hall AUSTRALASIAN MEDICAL PUBLISHING CO. LTD. 71-79 ARUNDEL ST., GLEBE, N.S.W., 2037 1975 ; / f ~ t \ A } ft a = cs ; 7 | y uth Wales 1975 PARTS 3 and | Wool Research in the Division of Protein Chemistry, CSIRO* W. G. CREWTHER AND F. G. LENNOX Apstract—Research in the Division of Protein Chemistry, CSIRO., relating to the bans, biosynthesis, structure and chemistry of the wool fibre and to the mechanisms involved in chemical if : ; I processing of wool has been reviewed. : studies in other laboratories. Introduction Owing to the importance of the sheep industry | in the Australian economy, research on wool ‘production and utilization has been given ‘a onsiderable support by the Australian Wool | Industry and the Australian Government. This || research includes a substantial amount of work || on the structure of wool and on its constituent _ proteins, thus providing an ever broadening | foundation for developing new wool processes | and for dealing with some of the more serious technical problems facing the industry in the i: Together with other aspects of wool | research, advances in research on the wool | proteins and their organization to form the wool | fibre have been critically surveyed at the | International Wool Textile Research Conferences | initiated in Australia in 1955 (Int. Wool Text. | Res. Conf., 1st, 1955) and held subsequently at Harrogate (Int. Wool Text. Res. Conf., 2nd, _ 1960), Paris (Int. Wool Text. Res. Conf., 3rd, | 1965) and San Francisco (Int. Wool Text. Res. | Conf., 4th, 1970). Such advances have also been ' Surveyed in recent reviews (Crewther ef al., 1965 ; Fraser et al., 1972 ; Bradbury, 1973). ‘ In the following brief account, some aspects of present knowledge on wool proteins are _ discussed in relation to current trends and | future needs. Reference is made to studies of | the intact fibre and its constituent cellular and ultra-structure, to the derivatization of the wool _ Proteins and their separation into fractions Tepresenting the major groups of proteins present in the fibre, to the further fractionation of these _ groups to yield individual protein chains and to the determination of amino acid sequences of some of these purified proteins. Attention is also drawn to what may well prove to be the most | ‘challenging and difficult aspects of the overall | programme. This is to ascertain the location | Of covalent crosslinkages in the native wool o _ * Invited paper. In some instances it has been necessary to refer to related fibre, how the sequences of the individual proteins determine their conformation within the fibre, to investigate their location and interaction with other proteins in the structure and their accessibility to, and interaction with, chemicals used in wool research and in wool processing. The ultimate goal is to know the location within the fibre of all the protein chains and the positions of their constituent amino- acid side-chains in relation to the histological and fine structural detail. Such studies may have to await the development of better experimental methods than those available at present. Meanwhile our expanding knowledge of the chemistry and structure of the wool fibre is providing new insights and new incentives to wool technologists who are endeavouring to develop new or improved processes in the wool textile industry. Biosynthesis and the Structure of the Wool Fibre The wool fibre is composed of a cortex con- taining elongated spindle-shaped cells covered by a cuticle comprising flat overlapping scale cells. These originate in separate layers of germinal cells situated just above the papilla at the base of the wool follicle in the skin of the sheep. The blood supply to the papilla is believed to be the source of the amino acids which are assembled into the wool proteins on polyribosomes located in the cells of the wool root. As the cortical and cuticle cells stream up the follicle they elongate or flatten respectively and, at a level corresponding to about one third of the height of the follicle, they lose their capacity to react with compounds used for detecting thiol groups, such as sodium nitroprusside, due to the oxidative conversion of thiol groups to disulphide groups. This reaction, which is the most significant feature of the fibre- hardening or keratinization process, is delayed if copper is deficient in the diet of the animal 96 W. G. CREWTHER anv W. G. LENNOX (Marston, 1946) and since no copper-containing oxidative enzyme has been detected in the follicle it is possible that the cupric, ion itself is responsible for catalyzing the crosslinking reaction. More recent studies using the electron microscope have shown that the cortical cells contain oriented filaments known as macrofibrils and that these consist of much smaller filaments known as microfibrils (Birbeck and Mercer, 1957 ; Rogers, 1959). The microfibrils are about seven nm in diameter and their centres are spaced about nine nm apart, the intermicro- fibrillar spaces being filled with an apparently amorphous matrix (see Fraser, MacRae and Rogers, 1972). The heavier staining of the matrix as compared with the microfibrils following partial reduction and treatment with osmic acid has led to the suggestion that the matrix has a higher cystine content than the microfibril (Birbeck and Mercer, 1957 ; Rogers and Filshie, 1962). Post-staining with lead salts after staining with osmic acid shows that the inner core of the individual microfibrils differs from the outer annulus. Evidence for this annular structure has been obtained also from X-ray diffraction and electron microscope studies (Bailey e¢ al., 1965; Millward, 1970; Fraser e¢ al., 1971). Attention is currently being directed to the determination of the more detailed structure of the microfibril through studies of fibrillar material extracted from the pre-keratin of rat vibrissae follicles (Whitmore, 1972a, b ; Jones, unpublished). Another interesting feature of the wool follicle is that the unusual amino acid citrulline occurs in the inner root sheath, where it appears to be associated with the proteins not incorporated in the so-called trichohyaline droplets. It also occurs in the medulla which is present as a central structure in coarse wool fibres and in hair (Rogers, 1963). Presumably citrulline is derived from arginine but the significance of its location in the follicle and fibre has yet to be determined. The protein of the medulla is insoluble in solutions containing reducing agents and protein disaggregating agents apparently due to the presence of e— (y-glutamyl)—lysine crosslinks (Harding and Rogers, 1971). It has also been shown that the proteins comprising «#—keratin can be synthesized in a cell-free system containing messenger RNA. During protein synthesis the ribosomes are grouped to form polyribosomes of three sizes and it has been suggested that the size of the polyribosome is directly related to the molecular yt io weight of the protein being synthesized, eac ribosome corresponding with about 30 amino — acid residues (Steinert and Rogers, 1971a, )). Additional information on the biosynthesis of © the fibre has been derived from an extension of earlier studies (Hardy, 1949, 1951 ; Hardy and Lyne, 1956) on the development of embryonic mouse hair and sheep skin in tissue culture. In the more recent studies hair from a young mouse was grown in tissue culture using collagen gel containing mouse embryonic diges as the culture medium (Frater and Whitmore, 1973). The cortical cells in the wool fibre appear to © be of two different types which differ in their © sub-cellular structure, in their uptake of stains such as with methylene blue or osmic acid and Wj" in their reaction with chemicals. In Merino Wj! fibres these cells have a bilateral distributio a (Horio and Kondo, 1953; Mercer, 1953) an constitute two adjacent strands known as thi ortho and para segments which twist around on another along the length of the fibre so that the ortho segment is always found on the outside oj each crimp wave (Fraser and Rogers, 1955; Wy: Fraser and MacRae, 1956). It has been Wy suggested that the formation of crimp in fin wools is due to the differential effect of moist on these two types of cell. In coarser, less- crimped wool fibres the two types of cell are not distributed bi-laterally. The reason for the difference in properties between the two types of cells is not known with any certainty, but! electron micrographs of fibre cross sections show that in the ortho cortex the microfibrils arew} frequently arranged in whorls whereas in the} Mj paracortex hexagonal packing is more common} (Rogers, 1959 ; Rogers and Filshie, 1962). Ini addition, the paracortical cells appear to contain} more high-sulphur matrix proteins between the? microfibrils than the orthocortex (Leach e¢ al.,) 1964). . The measurement of electron micrographs off stained sections of «keratin may give erroneous} data as a result of changes in dimensions during} staining. X-ray diffraction measurements ong the other hand are capable of providing more} precise information. Nonetheless, values for} the microfibrillar diameter (7-2 mm) and distance between centres of microfibrils (8-7 nim obtained from X-ray diffraction studies o porcupine quill (Fraser e¢ al., 1971) are similar to values obtained for other a-keratins electron microscopy. Synthetic polypeptides which .-adopt th a—-helical conformation give reflections col responding to a pitch of 0-54 nm and an axial . i t 4 268 Ss weeEes=xs sas foe & Ee B. SES FR FS RE FRE SFSPFSRSS_ FE nf ili! \ | one ai! di WOOL RESEARCH IN THE DIVISION : | | rise per residue of 0-15 nm. The high-angle diffraction pattern from «keratin on the other hand contains meridional arcs of spacing 0-515 and 0:149 nm. Crick (1952) and Pauling and Corey (1953) suggested independently that groups of a-helices were distorted to form two or three stranded coiled-coils which enable the residues on the inside of the assembly to pack together more neatly. The pattern obtained from «#—keratin agrees closely with that predicted for an a—helical coiled-coil rope (Fraser et al., 1964). Recent studies of the low-angle meridional and near-meridional low-angle pattern (Fraser Jjand MacRae, 1971, 1973) suggest that in the microfibril, the low-sulphur proteins are arranged on a helix with a unit height of 6-7 nm and pitch of 22 nm which is subject to a periodic axial distortion of period 23-5 nm. With progressive stretching of «—keratins, such as wool and hair fibres, in steam the characteristic 0-51 nm spacing along the fibre ) fis gradually replaced by a 0-34 nm spacing which \icharacterizes @-keratin, a different ordered atrangement in which the polypeptide molecular chains have been shown to be almost fully extended (Astbury and Woods, 1933; Fraser and Suzuki, 1970). This new meridional spacing is attributed to the mean axial distance between individual amino acid residues in the polypeptide chain. New reflections appearing in the equatorial pattern at 0-47 nm and 0-97 nm are ascribed to interchain and intersheet spacings Tespectively in pleated-sheet structures which are formed during mechanical extension of the fibre (Astbury and Sisson, 1935; Fraser e¢ al., 1969). ae and Isolation of Wool Proteins In parallel with biophysical studies of the intact fibre, investigations have been directed to the extraction of wool proteins and to their subsequent identification, fractionation, purific- ation and characterization. The studies to be described here were based on the earlier work of Goddard and Michaelis (1934, 1935) which showed that a high proportion of the proteins comprising «—keratins can be extracted at pH 11-12 after reduction of the disulphide bonds by Teagents such as thioglycollic acid or mer- captoethanol. Alternatively 6-8 M urea can be used as a disaggregating solvent thus permitting extraction at lower pH values (Jones and Mecham, 1943). The thiol groups in the wool proteins are then alkylated, preferably with lodoacetate to form S-carboxymethyl deriv- atives of kerateine, which have greater solubility OF PROTEIN CHEMISTRY, C.S.1.R.0. 97 than those obtained with alternative reagents, In our early research some fractionation of the proteins was obtained by a process of preferential extraction (Gillespie and Lennox, 1953, 1955a, 6) but in recent studies the objective has been to obtain maximum extraction of the proteins and subsequently to fractionate the protein mixture (Gillespie, 1972a). The present procedures have been developed in a series of studies (see Crewther et al., 1965 ; Bradbury, 1973 ; Fraser e¢ al., 1972) which show that the extractable proteins of the wool fibre are of three types differing greatly in structure and properties. As a result of these differences in properties it is possible to separate the three types of protein by fractional precipitation from solution. An outline of the procedure used and an indication of the approximate proportion of the wool proteins in each main fraction is shown in Figure 1. The largest protein fraction obtained by this procedure, which is designated the low-sulphur protein fraction because it contains only about 1:7% sulphur as compared with about 3:5% sulphur in the original fibre, consists of protein chains with molecular weights in the range 46,000-56,000 (Jeffrey, 1972; O’Donnell and Woods, 1956). The high-sulphur protein fraction, with a sulphur content of 4-5-6:5% depending on the breed and nutritional status of the sheep, contains protein chains with molecular weights between 10,000 and 25,000. On very good pastures, or when pen fed on a diet supplemented with formaldehyde-protected proteins, sheep may produce wool yielding a high-sulphur protein fraction containing as much as 7:0% sulphur containing chains with molecular weights as high as 30,000. The half- cystine content in such wool proteins is about 30 residues/100 residues. Proteins comprising the third type of extractable proteins are rich in glycine (up to 40 residues/100 residues) and tyrosine (up to 22 residues/100 residues) and contain 1:4 to 30% sulphur. They contain no methionine and usually relatively small proportions of lysine, histidine and isoleucine. These proteins all have molecular weights less: than 10,000 and can be classified as Type I or Type II high-tyrosine proteins according to their solubility properties (see Figure 1). There are a variety of alternative procedures available for rupturing the disulphide bonds of wool and producing soluble derivatives of the proteins. For example, tributyl phosphine (Maclaren e¢ al., 1968) has been shown to give virtually complete reduction of the disulphide bonds in a variety of solvents but after alkylation the amount of protein extracted is less than that 98 W. G. CREWTHER obtained by reduction with a thiol, alkylation, and extraction with similar solvent systems. Alternatively the disulphide groups can be oxidized to produce two sulphonic acid groups. Thompson and O’Donnell (1962) have shown that performic acid is preferable to peracetic acid (Alexander and Earland, 1950) for this purpose in that oxidation of the disulphide groups with performic acid is virtually complete without significant peptide hydrolysis. Merino Wool Reduce with thiol in aqueous urea (2RSH + WSSW > RSSR + 2WSH) React with iodoacetate Insoluble residue Cell walls and other debris (10%) Filtrate High-sulphur proteins (25%) Supernatant Add 2 vols acetone ammonium sulphate + 1/3 vol. sat. Precipitate Low-sulphur proteins (55%) FicurE 1.—Basic procedures used in separating the main protein constituents of wool. In addition, a number of different alkylating agents have been tested following reduction with 2—mercaptoethanol or mercaptoacetic acid in the presence of 8 M urea. S-—Cyanoethy]l, S—hydroxyethyl, S-carbamidomethyl kerateines have been produced but in each case the high- (WSH + ICH Soluble fraction Dialyse, add zinc acetate to 0.02 M, adjust pH to 6.0 Precipitate Suspend in 0.02 M sodium citrate, Type II proteins rich in glycine and tyrosine AND W. G. LENNOX sulphur protein fraction is virtually completely insoluble in aqueous buffers. As a result, these protein derivatives form a floccular precipitate when solutions of the kerateine derivatives in } 8 M urea are dialysed against distilled wate iy the low-sulphur proteins remaining in solution (Gillespie, 19635; Bhatnagar and Crewther, 1969). i After separating the wool proteins into} fractions containing the major protein types it iE coo. > WSCH 2 7C00H + HI) dialyse Precipitate Type I proteins rich in glycine and tyrosine (4%) Filtrate (6%) is necessary to identify the individual proteins) present in each fraction and to isolate each in a pure homogeneous state so that its chemical} structure, including the sequence_of the con- stituent amino acids, can be established. recently stressed by Sparrow (1972) this has WOOL RESEARCH IN THE DIVISION OF PROTEIN CHEMISTRY, C.S.1.R.O. proved to be a most difficult problem with keratins for several reasons. Firstly solubilized wool proteins have no known biological activity, such as enzymic or hormonal activity, that could be used to identify the chains and to follow the course of purification. Secondly, they show a marked tendency to aggregate, and disaggreg- ating agents such as urea must be present at high concentration during fractionation. Thirdly, each major protein type comprises a complex mixture of closely-related chains which, although apparently highly effective in conferring the desired mechanical properties on the fibre, greatly complicate the task of isolating pure protein species. Finally the S—carboxymethyl or other charged groups introduced into the structure to confer chemical stability and solubility tend to mask charge differences present on individual proteins prior to derivatization and so accentuate the difficulty of isolation. The greatest difficulty in fractionation and purification has been encountered with solutions of the low-sulphur proteins and this may be associated with the presence in these chains of a-helical regions which are stabilized by inter- action with «helical regions in other chains as shown by measurements of the optical rotatory dispersion of their solutions (Harrap, 1963 ; Crewther e¢ al., 1968). The rupture of these interchain associations is a necessary prerequisite to the isolation of the individual chain species. Usually 8 M urea has been used as a disaggreg- ating solvent for this purpose. The problem is exacerbated by the presence of several different chains in the low-sulphur fraction with large but similar molecular weights and similar amino acid compositions. When the S-carboxymethyl kerateines are subjected to starch-gel electrophoresis in 8 M urea several protein bands are produced, the most deeply-stained when numbered in order from the origin being bands seven and eight. These major bands are also present in electro- phoretograms of the low-sulphur protein fraction. Fractions enriched in the proteins corresponding with each of these two bands have been prepared in 8 M urea by stepwise elution from DEAE- cellulose columns at pH 8:6 and gel filtration of suitable fractions on Sephadex G—200 (O’Donnell and Thompson, 1964 ; Thompson and O’Donnell, 1965). Techniques have also been devised for the fractionational precipitation of ‘‘ component 7” and ‘component 8”’ from solutions of the low-sulphur protein fraction in aqueous x— propanol or 4 M LiBr to yield relatively pure preparations of both “ components’ (Dowling and Crewther, 1975). Amino acid sequence ht “k . 99 studies on the N-terminal section of “ com- ponent 8” showed it to consist of a mixture of closely-related proteins (Thompson and O’Donnell, 1967; O'Donnell and Thompson, 1968 ; O’Donnell, 1969). Immunodiffusion studies (Frater, 1968) and electrophoresis of the low-sulphur protein fraction on acrylamide gel slabs (Sparrow and Crewther, 1972) have recently shown that both “component 7 ’’ and “‘ component 8 ”’ comprise several different proteins which have been designated components 7a, b and c and com- ponents 8a, b, cl, c2 and c3 (Sparrow, McKern, Dowling and Crewther, private communication). By using shallow salt gradients on DEAE- cellulose combined with ion-exchange chrom- atography on SP—Sephadex it has been possible to resolve the low-sulphur protein complex into a number of fractions, some of which contain virtually pure components identifiable as 7c, 8a, 8b and 8c3. An alternative method of studying the low- sulphur protein complex has been by partial proteolysis, thereby excising most of the non- helical regions of the protein chains and permitting the precipitation of helix-enriched fragments at pH 4-0 in the form of triple chain particles 160 A in length, about 20 A in diameter and of molecular weight about 40,000 (Crewther and Harrap, 1967 ; Crewther and Dowling, 1971 ; Dobb et al., 1973 ; Suzuki e¢ al., 1973). There is evidence for at least three types of «helical segments in the low-sulphur proteins and two of these have been identified as individual chain segments of about 100 residues in the triple- chain particle and prepared in a state of considerable purity. The complete amino acid sequence of one such chain segment has been elucidated (Hogg, Dowling, Crewther, Inglis and McKern, unpublished) and sequence studies on the other helical segments are in _ progress (Gough, Inglis, Dowling and Crewther, unpub- lished). The high-sulphur wool proteins, which remain in solution when the low-sulphur and_high- glycine-tyrosine proteins are precipitated with zinc acetate at pH 6, have been fractionated by several methods including ammonium sulphate precipitation and chromatography on DEAE-cellulose, cellulose phosphate and SE- Sephadex. The extreme heterogeneity of the unfractionated high-sulphur wool protein prep- aration compared with other protein systems has been clearly demonstrated by the elec- trophoretic mobility of their protein constituents (Joubert et al., 1968), by their behaviour during ion exchange chromatography and gel filtration 100 (Joubert et al., 1968 ; Gillespie, 1963) ; Darskus et al., 1969; Darskus, 1972) and by immuno- diffusion techniques (Frater, 1969). One high- sulphur protein preparation from wool, designated SCMK-B2, was originally believed to be a single protein (Gillespie, 1963a) but was later shown to consist of a family of closely- related proteins all lacking lysine, histidine and methionine from which four different protein chains were recovered in a sufficiently pure state for sequence studies (Lindley and Elleman, 1972). Some of the high-tyrosine proteins are very easily extracted from wool with alkaline thioglycollate solution (Gillespie and Lennox, 1955a; Simmonds and Stell, 1955; DeDeur- waerder et al., 1964). They are also readily recoverable from wool by extraction with 50% formic acid (Zahn and Biela, 1968a, b). In the studies of Gillespie and Darskus (1971) these proteins were precipitated together with the low-sulphur proteins at pH 6-0 by the addition of zinc acetate and ammonia. After solution of the precipitate in 0-02 M sodium citrate and dialysis against deionized water the high-tyrosine proteins could be divided into two types on the basis of their solubility in deionized water (Figure 1). The insoluble Type I proteins were then collected and dissolved in aqueous ammonia, presumably by ionization of phenolic side-chains of tyrosine residues. The soluble Type II proteins were recovered from the low-sulphur protein fraction, by utilizing their greater solubility in aqueous acetone in the presence of ammonium sulphate. The identification and fractionation of this family of proteins has been greatly facilitated by the use of electrophoresis on cellulose acetate (Blagrove e¢ al., 1975). The proteins rich in glycine and tyrosine are characterized by relatively low molecular weights (<10,000) and by the restricted range of amino acid residues constituting individual chains. In many instances glycine and tyrosine residues constitute about 50°% of the residues in the molecule. All chains are devoid of methionine and some contain little or no lysine, histidine, isoleucine or glutamic acid (Gillespie, 1972; Gillespie and Frenkel, 19746). One Type II high-tyrosine chain has been shown by Gillespie and Frenkel (unpublished) to contain only 11 different amino acid residues. Approximately 80% of the molecule was found to consist of glycine, tyrosine, serine and cystine. Ion exchange chromatography and isoelectric focussing of the Type I family of high-tyrosine proteins have shown the presence of thirty to forty different protein species belonging to about ten families. W. G. CREWTHER anp W. G. LENNOX 1 a ., The significance of this heterogeneity, like that } of the high-sulphur and low-sulphur proteins, is | a not yet understood (Gillespie and Frenkel, } *“ 19745, c). o Attention has been focussed mainly on thi ‘ proteins extractable from wool because method: 4 are available for studying their structures 4 There is an equal need, however, to know they P molecular structure of proteins located in the i membranes isolated from wool. In preliminary | ™ studies on the composition of the epicuticle, 2 chemically inert and very thin membrane which is released from the surface of wool fibres by 4 treatment with chlorine and vigorous agitation, |} ™ it was shown to be rich in serine, glycine, cystine § and glutamic acid (King and Bradbury, 19657R The membranous residue from wool obtained by oxidation with performic acid and extractior with ammonia or urea (Bradbury e¢ al., 1971 closely resembles the epicuticle in amino aci¢ composition. It is also desirable to learn more \ about the lipid in wool of which about 1% is released when the fibre is treated with formic] . acid (Bradbury et al., 1965; Bradbury and} King, 1967). Lipid is also released during prolonged extraction with alkaline thioglycollate (Lennox, unpublished). This material appee to be relatively inaccessible and may well ha an important influence on the penetration of chemicals into the fibre. Influence of Breed and Nutrition of Sheep — on Wool Proteins : Before rapid methods for estimating amino / acids and techniques for solubilizing and ~ fractionating wool proteins became available, intact wool was frequently subjected to chemical © analysis for particular elements, such as nitrogen | and sulphur, and on account of the relative | constancy of the values obtained wool was | assumed to have a constant composition ) (Marston, 1946). However, it is now known © that even wool from a single sheep can vary in f th composition to a considerable degree. For } i example, the rate of growth and the cystine | content of wool are increased by abomasal } infusion of cystine or sulphur-rich proteins (Reis |} and Schinkel, 1963) and there are other major | changes in the overall amino acid composition of | the wool (Gillespie, 1965 ; Gillespie and Reis, | 1966; Gillespie and Darskus, 1971). is | change was found to be associated with 4 variation in the proportions of the constituent — low-sulphur, high-sulphur and_high-glycine- | tyrosine proteins. Variations in the content of high-sulphur proteins in wool between 18% and 34% have been attributed to both genetic and WOOL RESEARCH IN THE DIVISION dietary factors (Gillespie and Reis, 1966 ; Campbell et al., 1972). The role of the former is evidenced by the differences observed between fleeces produced by different sheep in the one flock grazing on the same pasture. The importance of diet is seen in the effects of changes in the nutrition of individual sheep on the composition of the wool produced. One conspicuous feature of the wool from sheep fed on a high-protein diet containing adequate amounts of the sulphur-containing amino acids is the increase in the proportion of a group of proteins in the wool designated “ ultra-high- sulphur” proteins which contain some 30 residues per cent of half-cystine residues (Lindley ét al., 1971). 1 2 3 4 5 7 8 ) OF PROTEIN CHEMISTRY, C.S.1.R.O. 101 synthetic steroid, opticortenol, or abomasal infusion of methionine to sheep maintained on a wheat diet, result in weak wool and in some cases defleecing of the animal occurs. The relationship between the synthesis of high- tyrosine proteins and defleecing is not understood (Frenkel, Gillespie and Reis, unpublished). Amino Acid Sequences in Wool The relative proportions of the various amino acids and the sequence in which they are linked together in the peptide chain or chains of a protein exert a profound effect on its properties. They largely determine the conformation the protein will assume in a particular environment, how it will interact with other proteins in the 10 11 12 13 14 15 16 17 18 GLN-ASN-ARG— GLN-CMC-CMC- GLU-SE R-ASN-LEU-GLU-PRO-LEU-PHE-SER-GLY-TY R-ILE-— 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 = 36 —GLU-THR-LEU-A RG-ARG-GLU-—ALA-GLU-CMC-VAL-GLU-ALA-ASP-SER-GLY-ARG—LEU-SER- 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 —SER-GLU-LEU-ASN-LEU-VAL-GLN-GLU-VAL-GLU-GLU-CMC-T Y R-GLU-ARG-—A RG-TY R-GLU- 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 ae 72 —GLU-GLU-ILE-ALA-LEU-ARG—-ALA-THR-ALA-GLU-ASN-GLU-PHE-VAL-ALA-LEU-LYS-LYS- Om ass TOS nn LOD, ace 78 79 80 81 82 83 84 85 86 = 87 88 89 90 —ASP-VAL-ASP-CMC-ALA-T Y R-LEU-ARG-LYS-SE R-ASP-LEU-GLU-ALA-ASN-V AL-GLU-ALA— Sienos eo. One Toor 90)" 07. 98 99 100 101 102 1038 104 4105 4106 #107 #108 109 LEU-ILE-GLN-GLU-THR-ASP-PHE-LEU-ARG-ARG-LEU-TY R-GLU-GLU-GLU-ILE-ARG-VAL-LEU Ficure 2.—The amino acid sequence of the Type II helical peptide segment recovered from the helical fragments produced by partial proteolysis of the low-sulphur wool protein SCMK—A, with chymotrypsin. S—Carboxy- methylcysteine residues are indicated by CMC. Similarly it has been shown that variations in the tyrosine content of wool between about 2:3 and 4:3% of the amino acid residues are associated with changes in the content of the proteins rich in glycine and tyrosine (Gillespie and Darskus, 1971; Gillespie and Frenkel, 1974a ; Frenkel e¢ al., 1974). As with variations in cystine content, these variations also can be related to dietary and genetic changes in the ‘sheep. Experimentally a reduction in the content of proteins rich in glycine and tyrosine in the wool can be readily induced by infusions of zein, maize gluten, wheat gluten or an amino acid mixture corresponding in composition to zein, into the abomasum of the sheep. Inter- ference with the metabolism of the aromatic amino acids has been suggested to explain the effect. Other treatments of the sheep causing a similar inhibition of the synthesis of the high- tyrosine proteins, such as intravenous infusion of mimosine, intravenous injection of the vicinity with chemicals, how it is affected by irradiation of all types, and in the case of a fibrous protein, how the fibre behaves when subjected to mechanical stress. The amino acid sequences and the architecture of the proteins of wool also determine the resistance of the fibre to digestion by proteolytic enzymes and its susceptibility to digestion in the gut of the clothes moth larva and the carpet beetle. It is therefore important to ascertain the amino acid composition and sequence of those proteins which can be isolated from wool in a sufficiently pure state. This has been facilitated by the construction of an automatic amino acid sequenator and the improvement of existing methods for the identification of amino acid derivatives and for the determination of the sequences of small peptides using the machine (Crewther and Inglis, unpublished ; Inglis and Nicholls, unpublished ; Inglis e¢ a/., 1974). The family of low-sulphur wool proteins known as component 8, has been cleaved with cyanogen 102 bromide and a 77-residue peptide from the N-terminus has been partly sequenced (Hosken et al., 1968) and more recently partial sequences have been determined (Figure 2) for helical peptides isolated from the mixed low-sulphur proteins of wool (Hogg ef al., 1971; Inglis, McKern and Crewther, unpublished ; Gough, Inglis and Crewther, unpublished). These sequences show a clear pattern in which hydro- phobic residues occur at positions 1, 4 or 5, 8, 11 or 12, 15, 18 or 19, and so on (Figure 2), thus producing a band of hydrophobic side-chains W. G. CREWTHER anv W. G. LENNOX 1971 ; Dopheide and Elleman, 1972). As will be noted from Figure 3, these three proteins are highly homologous and a large part of each is made up of variant repetitions of the decapeptide | sequence Thr—Ser—Cys—Cys—Glu—Pro—Thr—Cys— § Ile—Glu. An interesting feature of the high-sulphur and low-sulphur protein sequences studied so far is § that in most instances the N-terminal amino § acid residues were found to be acetylated. the former the terminus is acetyl-alanine | (Figure 3) and in component 8, the only low- B2A Thr—Gly B2B...Ac—Ala~-CMC—CMC-Ser—Thr-Ser—~Phe—CMC--Gly—Phe—Pro-Ile-CMC-Ser-—| Ser—Val |-Gly-Thr—CMC-Gly— B2C Thr—Ala Pro—CMC-Gln-—Pro |- CMC Ser—Ser—| CMC-—Gly—Gln—Pro |-Thr—CMC- | Ser |-Gln—Thr—Ser-CMC—CMC-GIn-Pro-Thr—Ser—e-Gln— CMC-—CMC-Arg—Ser Ser Thr—Ser-CMC—CMC-GIn—Pro-Ile—Ser—Ile—GIn—Thr—Ser-CMC-—CMC-Gln—Pro-Thr Ser—Ile—Gln— Thr—Ser—-CMC—CMC-Gln-—Pro-Thr CMC-Leu-—Gln—Thr—Ser—Gly—CMC-Glu-Thr—Gly—CMC-Gly—Ie— Gly-Gly-Ser—Ile—~Tyr—Gly “hoy -Gln-Val-Gly—Ser—Ser-Gly—Ala~Val-Ser-Ser-Arg-Thr-Arg- Trp—CMC—Arg—Pro—Asp-CMC-Arg-Val-Glu—Gly—Thr—Ser—Leu—Pro—Pro—CMC-—CMC-Val-Val—Ser— Pro CMC-Thr— Ser Tyr—CMC-Gly—Gln—Ser-CMC-—CMC-—Arg—Pro—Ala~-CMC-—CMC-CMC-GIn-—Pro-Thr—CMC- Ser CMC-—Glu—Pro-—'Thr CMC-— Ser/-Pro-Ser CMC-CMC-GIn-Leu—Tyr—Tyr—Ala—Gln—Ala—Ser-CMC-—CMC—Arg—Pro-Ser— Tle lle Thr —Glu—Pro-— CMC-Glu—Pro-Thr—CMC Vv al ) Thr Ser—G]n—Pro—Ile—CMC FIGURE 3.—Comparison of the amino acid sequences of high-sulphur wool proteins SCMK—B2A and SCMK-B2C | with that of SCMK-—B2B. when the sequence is arranged in the form of a 3°6 residue/turn helix. This could be considered diagnostic for a coiled-coil structure of the form proposed by Crick (1952, 1953) and Pauling and Corey (1953). Among the high-sulphur proteins three individual structures, each containing about 100 residues, have been isolated and sequenced in South Africa (Haylett and Swart, 1969 ; Haylett et al., 1971) and three other high-sulphur proteins belonging to another family and having 171, 156 and 151 residues per molecule (Figure 3) have been sequenced in Australia (Elleman, Sequence differences are enclosed in boxes. Sequence deletions are indicated by lines. ? sulphur chain for which the N-terminal sequence is known, it is acetyl-serine (O'Donnell and Thompson, 1968). By contrast, in the high- | tryosine proteins examined so far, the N— terminal amino groups are free (Dopheide, 1973, unpublished data ; Marshall, unpublished data). Other important features of these sequences are that many of the residues occur in pairs, and also, especially in the high-sulphur proteins, — there are many examples of the same or closely similar sequences of amino acid residues being | repeated in the same molecule. This suggests that the genes for these proteins have arisen | . | j | In § I - | a ae - — ee = sly | WOOL RESEARCH IN THE DIVISION from the duplication of smaller genes with subsequent mutations arising in most instances | from single base changes in the codons specifying certain amino acids (Elleman ef al., 1973). Many of the proteins in wool appear to have been derived from common ancestors. The high-glycine-tryosine proteins, being of low molecular weight, are readily extracted from wool by a variety of solutions, and the individual protein species are somewhat easier to separate from one another during fractionation than those of the low-sulphur and high-sulphur groups. The sequence of a member of the Type I sub- group of high-tryosine proteins (Dopheide, 1973) is shown in Figure 4. The amino acid sequence of this protein is necessarily dominated by the glycine residues. However, no pattern is apparent in the arrangement of the glycine residues and it will be necessary to determine the sequences of other related proteins to | determine which residues, if any, play an essential role before any structure for these {| proteins can be postulated. However if certain deletions or insertions are accepted it is con- OF PROTEIN, CHEMISTRY, C/S:1:R.O. 103 preferentially liberated as the disulphide bonds are progressively converted to S—carboxymethyl groups. This study may give preliminary information about the distribution of reactive and less reactive disulphide bonds. Location of Proteins in the Intact Fibre While it is essential in the determination of the complete structure of wool to know the sequence of the amino acid residues in each protein, it is likewise important to know the location and conformation of the proteins in the wool fibre and their interrelationship with one another. Electron micrographs of cross sections of wool fibres reduced and stained with osmium tetroxide suggest that the low-sulphur proteins comprise the microfibrils whereas the high-sulphur proteins are located in the matrix. Initially the proteins rich in glycine and tryosine were believed to be located in the inter-cellular regions in the wool fibre (DeDeurwaerder ef al., 1964) but the amount extractable from Merino wool (up to 12%) is too large to be wholly accom- Ser—T yr-CMC—Phe-Ser—Ser—Thr—Val—Phe—Pro—Gly—CMC-Tyr-—Trp-—Gly—Ser-T yr—Gly—T yr—Pro-— Leu—Gly—Tyr—Ser—Val—Gly—CMC-Gly—T yr—Gly—Ser—Thr~-T yr—Ser—Pro-—Val-Gly—T yr—Gly—Phe— Gly—Tyr-Gly—Tyr—Asp—Gly—Gly—Ser—Ala—Phe-Gly-CMC-—Arg—Arg—Phe—Trp—Pro—Phe—Ala—Leu—Tyr Figure 4.—Amino acid sequence of the high-tyrosine protein, component 0-62. ceivable that portions of these chains show a decapeptide “repeat ’’ which may be related to the “repeat” in the high-sulphur protein sequences (Lindley, unpublished). On the other hand the high content of relatively few amino | acids in this chain gives a high probability of | such repeats at intervals of 10 residues assuming a random distribution of residues and further information is needed before the decapeptide- | repeat hypothesis can be tested. Once the amino acid sequence of each major constituent of wool has been determined it will ‘be possible to collect information about the | positions of interchain and intrachain disulphide | linkages in the fibre. _about the distribution of disulphide bonds in As yet little is known wool. Lindley and Cranston (1974) have shown | that the reactivity of these bonds with thio- glycollate, and hence the ease with which they can be ruptured is greatly affected by the nature of the adjacent amino acid residues. Disulphide || groups in proximity to polar residues appeared to be more reactive than those associated with non-polar residues. This work is being extended to determine which protein chains are modated at this site. The current view (Fraser et al., 1973) is that a-keratins contain a variable proportion of these proteins located in the matrix with associated high-sulphur proteins. This is based on the observation that the volume ratio, matrix/microfibril, as determined by X-ray diffraction measurements approximates closely the mass ratio, high-sulphur protein + high-tryosine protein/low-sulphur protein. An alternative means of determining the location of the proteins is to isolate the individual histological components of the fibre by methods involving minimum damage to the constituent proteins. These can then be extracted by conventional methods and individual proteins identified by chromatographic and_ electro- phoretic techniques developed for the proteins of the intact fibre. Mechanical disruption of fibres swollen in formic acid appears to be the most acceptable method at present available for preparing sufficient cuticle and cortical cells for amino acid analysis (Bradbury et al., 1965; Bradbury e¢ al., 1966) and both types of cell have now been prepared in sufficient quantity for protein fractionation (Ley, unpublished). 104 An alternative approach for locating various types of protein in the wool follicle is now being explored. Antibodies to purified wool proteins are prepared by injecting them into rabbits and the antibodies are then labelled with a fluorescent dye or the enzyme peroxidase. The binding sites of these labelled antibodies in sections of skin are then determined using fluorescence microscopy (Frater, unpublished) or by the production of a coloured product when peroxidase constitutes the label. Earlier studies on the preparation of antibodies to wool proteins for studies on the homogeneity of wool protein preparations (Frater, 1968, 1969) suggested that such methods are feasible. Chemical Reactivity in Relation to the Utilization of Wool The effects of chemicals, physical deformation, heat and various types of radiation on wool reflect the susceptibility to modification by these treatments of the terminal and side-chain groups, the main chain peptide bonds and crosslinks such as disulphide groups. The rate at which the wool fibre is modified in this way is a function of both the reactivity and the accessibility of the various reactive sites. Accessibility to chemical reagents may be increased, for example, by swelling in water or by mechanical, biological or other forms of damage or pre-treatment. fa HN \ NH CH=CH, -SH "GH 2 > Ns Cc=0 J As with other protein materials, wool is very susceptible to damage by highly alkaline solutions, especially at elevated temperatures. Hydrolysis of the amide bonds in glutamine and asparagine residues is liable to occur with liberation of ammonia, also peptide bonds in the main chain and disulphide crosslinks are liable to be broken. The hydrolytic products formed from cystine residues in this way can be further degraded to form «—aminoacrylic acid residues which then react with cysteine residues, another major product from the hydrolysis of cystine, to form lanthionine residues. The extent of this reaction is determined by the activity of hydroxyl ions within the wool fibre ionic strength of the liquor surrounding the fibre (Crewther and Dowling, 1965). Yellowing of the fibre is also a problem if wool is heated in solutions at pH values greater than seven J (Lennox, 1960) and the underlying chemical | changes are more complicated than the hydro- — lytic reactions referred to above. Thus in the process of scouring greasy wool to remove wax, © suint and dirt, discoloration and tendering are liable to occur if the pH and the temperature of | the scouring liquor are not carefully controlled, Such difficulties are more likely to be encountered with the older method of soap-soda scouring than the newer methods employing synthetic detergents which are effective in neutral | solutions. At pH values less than seven, damage to wool } is less likely partly because the “ ppcenuay point’ of the fibre lies in the vicinity of pH 5 | so that swelling of the fibre is minimal in dilute {| acid and partly because disulphide groups are } more stable to acid than to alkali. For this | reason the dyeing of wool with acid dyes, which carry sulphonic acid groups to render them | soluble, normally produces little appreciable § damage even though it may involve boiling in ~ dilute acid solution for prolonged periods. Similarly wool can be dyed without apparent | damage in cold concentrated formic acid | F x HN NH = CH-CH,,-S-CH,-CH Zee ‘ C=0 / (Harrap, 1959 ; Milligan, 1961), a process that laid the foundations of modern methods for the cold dyeing of wool in aqueous solvents. The method of choice for the removal of vegetable matter from clean wool involves a more severe acid treatment. The wool is soaked in dilute sulphuric acid and hot air is forced through the wool to evaporate the water and concentrate the acid. The wool is then baked at a temper- ature frequently greater than 100°C to char and embrittle the burr and other vegetable matter SS A A . which can then be powdered and shaken out | from the wool. Damage can be minimized | during carbonizing by the addition of certain J ; § | H thal § coloration. WOOL RESEARCH IN THE DIVISION OF PROTEIN CHEMISTRY, C.S.LR.O. wetting agents to the acid bowl used for soaking (Crewther, 1955 ; Crewther and Pressley, 1958). Reaction with excess concentrated sulphuric acid causes sulphation of the serine and threonine residues in the wool proteins and virtually eliminates the affinity of wool for acid dyes (Maclaren and Kirkpatrick, 1970), an effect that is sometimes observed when wool is carbonized under excessively severe conditions. Since acids degrade wool by hydrolysis to its constituent amino acids the conditions of exposure to acid solutions must be carefully controlled. As with alkaline treatments, the ionic strength of the acid solutions has a major effect on the hydrogen ion activity within the fibre and hence on the extent of fibre damage at a particular pH of the external solution. Peptide bonds adjacent to aspartic acid residues are particularly susceptible to hydrolysis in dilute acid solutions (Leach, 1955). The proteins of wool are also susceptible to damage by light, especially in the presence of moisture. This is evidenced by chemical changes in the wool, loss in strength and dis- These changes are associated with the photooxidation of the cystine residues through a series of partial oxidation stages to the formation of two cysteic acid residues (Sweetman ef al., 1965). Such breakdown contributes to loss in strength of the fibre and to the production of negatively charged centres which change its affinity for dyes and other ionic compounds. Accompanying the loss in strength, and usually apparent at an earlier stage, yellowing discoloration is observed which appears to be associated with the photooxidation of the tryptophan residues in the wool (Lennox and Rowlands, 1969). The tips of wool fibres in the animal's fleece are particularly susceptible to chemical changes of this type and because of the concomitant loss in strength much of this damaged fibre is lost during processing. Much attention has been given to the ‘thf » chemistry of the photodegradation of tryptophan The alee vere lute the rate pee anda tel oul ine ' {alll s he aa which proceeds through several intermediates giving rise to formyl kynurenine. Intermediates not previously recognized have been isolated and identified in the course of this work (Savige, 1971), but the chemical nature of the yellow » product or products resulting from the photo- oxidation of wool remains unknown. Evidence for the formation of polymerized yellow products from tryptophan residues has been obtained (Holt and Milligan, 1973) but so far these have resisted attempts at identification. A further complication is that fluorescent whitening agents, which are applied to textiles to enhance their 105 brightness and whiteness, catalyze the yellowing of wool by light. This is a major problem for the industry and a considerable amount of research has been directed to elucidating its nature and to minimizing its effects. Whereas the photoyellowing of untreated wool becomes more pronounced the further the radiation extends into the ultra-violet region and is a significant problem only in summer, that of a fluorescently whitened wool fabric occurs most rapidly at the absorption maximum of the fluorescent whitening agent employed and occurs in all seasons (Leaver and Ramsay, 1969). Also by treatment of wool with a stilbene or pyrazo- line fluorescent whitening agent containing a radioactive marker prior to irradiation it has been shown that the whitening agent becomes covalently bound to the wool during exposure (Milligan and Holt, 1973). Currently attention is being given to the synthesis of new fluorescent whitening agents and to new methods of application to the fibre in order to understand the mechanism of the yellowing processes, and eventually to achieve a better performance on wool. It has been shown that partial protection against photoyellowing can be conferred by impregnating wool fabric with thiourea and formaldehyde (Milligan and Tucker, 1964) but this treatment is not completely fast to washing and the residual protective effect following laundering is not sufficient to justify widespread adoption of the treatment. The protective action of these chemicals is probably associated firstly with the restriction of conformational changes due to the introduction of methylene bridges by reaction of formaldehyde with side- chain groups and secondly to the reductive bleaching effect of the thiol groups of the thiourea. It has recently been shown (Gee, unpublished) that a wide range of thiols or other reducing agents (Holt et al., 1974) give similar beneficial effects. The setting of wool fabrics to assist retention of creases or pleats is known to involve chemical changes in the cystine residues of the wool proteins. Reagents such as _ bisulphite or thioglycollate which increase the thiol content of the wool are widely used commercially as setting agents for wool fabrics, for example, to impart permanent creases. It has been shown that the increase in thiol content facilitates thiol-disulphide exchange reactions within the fibres. This reaction in turn allows mechanical stress to be relieved within the fibre as the proteins take up new conformations (Caldwell et al., 1964). 106 Many shrink-proofing treatments for wool fabrics also involve the chemical modification of disulphide groups. Oxidizing treatments which convert the disulphide bonds to sulphonic acid groups confer shrink resistance on wool presumably by softening the scale edges and roughening the surface of the scales. This greatly decreases felting which is due, at least in part, to the ratchet action between adjacent fibres as the unidirectional scales of one fibre slide over their counterparts in the other, thus preventing them from returning to their original positions after each distortion of the fabric brought about by mechanical agitation during laundering. It has been shown that when permanganate solutions containing common salt are used as a wet chlorination process for shrinkproofing wool a subsequent treatment with sodium sulphite greatly enhances the shrinkproofing effect (McPhee, 1963). This observation finds a ready explanation in a study on the intermediates formed during oxidation of disulphide groups in proteins and_ simpler compounds. Intermediate oxidation states of the form —SO.S— or —SO,S— were shown to be formed with a variety of oxidizing agents, including halogens. When these intermediates were reacted with sulphite the products of the reaction were shown to contain sulphonate groups and thiosulphate groups. The reaction of oxidized disulphide groups with sulphite is probably as follows : WS-SO. W-+S03-->WS-SO3 + WSO- WSO-+S03-+H+->WS-SO3 +OH- WS-SO,. W-+S03-->WS-SO3 +-WSO2 and the rupture of crosslinkages together with the consequent solution of proteins, accounts for the greatly increased shrinkproofing effect following treatment with sulphite (Sweetman and Maclaren, 1965). An investigation of the mechanism of the chlorination reaction which is unique in its shrinkproofing effect has shown (Gordon, unpublished data) that chlorine attacks not only disulphide bonds but also peptide bonds adjacent to certain amino acid residues. It is therefore effective in producing soluble sections of peptide chain which can then exert a large osmotic effect and cause extensive surface damage to the wool fibres. The traditional dyeing procedures used for wool fabrics depend on electrostatic attractions between ionic groups on the dye molecule and those on the wool proteins for binding of the dye by the fibre. Negatively-charged sulphonate groups on acid dyes interact with the positively- charged groups of lysine and arginine residues are in the fibre and these attractions W. G. CREWTHER anp W. G. LENNOX supplemented by hydrogen bonding and hydro- phobic bonding between the proteins and appropriate regions of the dye structure. That the ionic effect is preeminent is shown by the — fact that the number of ionizable basic groups in — the fibre can be assessed by determining the amounts of acid dyes bound by the wool — (Maclaren, 1960). Greater washfastness of dyes is achieved by the use of chrome dyes which rely for their effectiveness on the formation 7m situ of a very large complex between chromic ions and the dyestuff which is too large to diffuse out of the fibre (Hartley, 1969). The normal electrostatic and hydrophobic binding of acid dyes are operative in the older and cheaper process of chrome dyeing during which the chrome salts © and the dye are applied to the wool in separate treatments. In the meta-chrome process the two reagents are applied simultaneously. The great advantages of chrome dyeing are the high levels of washfastness and lightfastness achieved. On the other hand the shades obtained are relatively dull and it is partly for this reason / and the need for high levels of washfastness and bright shades in certain end uses that the so- called reactive dyes, which form covalent bonds with wool, have been developed and are growing in popularity. lysine, histidine, serine, tryosine or cysteine oF The reactive dyes interact principally with the — 4 I ; 4 I residues in the wool proteins by displacement or | addition reactions. excellent fastness to washing and cover a very wide range of shades. is sometimes poor compared with the chrome dyes. One widely used class of reactive dyes carries a sulphuric acid ester grouping which is converted to a vinyl sulphone on treatment with alkali. In weakly acid solution these groups interact readily with the lysine and N-terminal amino groups in wool to produce a covalent bond. Although the main purpose of inserting reactive groups on dyes is to increase wash- fastness it has been observed for example with a particular Astrazon dye (Gale and Wilshire, 1974a, 6) that the insertion of the reactive groups, N—2, 3-dibromopropionyl and N—chloro- difluoropyrimidyl, into the dye can also impart improved lightfastness to the dye after reaction with the wool fibre. The Thiolan dyes which carry isothiuronium groups have been developed as a new class of reactive dyes for wool (Guise and Stapleton, 1973). After the dye has been distributed evenly throughout the wool, the pH of the — dyebath is raised to decompose the isothiuronium — However the lightfastness ~ In general, they display A <. = = er ge Ss ee eas as ee eee es oe in The Garra Formation (Early Devonian) at Wellington, N.S.W. d BRIAN D. JOHNSON f : nai Axsstract—Andesitic volcanics, often regarded as Ordovician, but here referred to the Early Devonian Cuga Burga Volcanics, out-crop in a much faulted, north plunging anticline in the a ’ Wellington Caves area. The volcanics are overlain by the Garra Formation. The latter commences all with an apparently transgressive sequence of volcanically derived sediments grading from con- he glomerates and siltstones through to marine shales and these in turn into limestones at the base ie of a carbonate sequence some 970 metres in thickness. It is contended that a complete sequence of At. the Garra Formation exists in the Wellington area and that this can be informally divided into 20 | units. After the initial transgressive phase, subtidal marine carbonates were deposited on a shallow ap || platform ; the upper half of the formation is characterized by extensive sabkha style deposition on ld | intertidal and supratidal flats. Conodonts indicate correlation of the basal Garra limestones with es Introduction Richly fossiliferous horizons have long been i | known to occur in the limestones of the Garra | Formation near the Wellington Caves, south of 7 die Nellington, N.S.W., but their stratigraphic | sequence and faunal ‘composition have not been =| detailed; with the exception of the corals, | (Strusz, 19655, 1966, 1967, Strusz and Jell, ‘nf “| 970) the diverse invertebrate faunas have m |Feceived little attention. Mapping of the | Wellington Caves area was undertaken to | determine the field relationships of the Garra | Formation to contiguous units and to establish a | the stratigraphic and lithologic sequence as a | basis for palaeoecological analysis of the faunas. < | The area (Figure 1) forms part of the eastern 1! flank of the Molong High. The oldest outcrops n the region are Ordovician spilites and grapto- Hitic shales (Oakdale Formation) overlain by fossiliferous Silurian limestones (Narragal Lime- stone) and graptolitic shales (Barnby Hills | Shale). Andesitic vulcanism, with extensive |intermediate lavas and detrital deposits, com- _|menced at or about the close of the Silurian and continued into the Early Devonian (Cuga Burga | Volcanics). All the above outcrop typically | along the Oakdale Anticline (Strusz, 1960) to the east of the Caves area. | _ The oldest outcrops within the area mapped | are lavas, herein assigned to the Cuga Burga Volcanics. These are overlain by a thick | sequence of Early Devonian limestones | Tepresenting an eastward extension from a major | meridional belt of limestones, the Garra Formation (Strusz, 1965a), and physically parated from it by a synclinal belt of Late the limestones at the base of the Mandagery Park Formation (late Lochkovian-early Praguian). Devonian quartz rich clastics, the Catombal Group (Conolly, 1963; Roberts e al., 1972). There is no further sedimentary record of events until the late Cainozoic when the various alluvials of the present drainage system accumulated. Stratigraphy Cuga Burga Volcanics Andesitic lavas, tuffs and detrital sediments of volcanic derivation, previously regarded as Ordovician in age (e.g. Adrian, 1971) and so indicated on the Dubbo 1 : 250,000 geological sheet (Offenburg et al., 1968), are here assigned to the Cuga Burga Volcanics as defined by Strusz (1960) ; this assignment has been implied previously by Strusz (1967a), Savage (1968) and Druce (1970). Correlation is indicated by the close petrographic similarities to the typical Cuga Burga outcrops mapped by Strusz (1960) and, more important, by field relationships in the area north of Newrea (south east of the Wellington Caves) where these volcanics are seen to be underlain by the Late Silurian Barnby Hills Shale. Owing to the weathered nature and lack of stratification in most outcrops, precise relation- ships and thicknesses are not clear. The better exposures to the south (‘ Camelford Ridge ’) are massive and strongly jointed, making bedding difficult to determine. The lowest outcrops are a suite of breccias with coarse angular, andesitic clasts and minor red lithic tuffs. They are overlain by green andesites grading into dark red and purple andesites with quartz veins and disseminated copper. BRIAN D. JOHNSON 112 Golf Club Nes “20 Nvawoly Mountain // View * // Mountain Y Valley yi Vv f) Mocqu WELLINGTON ) AREA orie YC ) * WELLINGTON CAVES t ES LL O — O oO al O ld O Wellington Z 500 metres 200 300 400 100 te} Undifferentiated high terrace deposits , colluvium in places ond deep soil cover Alluvial fons derived from Catombal Group — terraced ig Flood plain deposits , silts, sand, gravels ee ey Asousajono Sondstones, shales, conglomerates CATOMBAL GROUP uoluonag 2105 Andesitic lavos & tuffs « s 5 ¢ € 3 = 2 > a 2 Fe 2 = 2 = < S o ° S S a o Ss s oS = 2 2 $ 2 S $ S 3 xz 3 = S s ' = a 3 2 6 a = re) gee 3 o > < a ra c > oa < Qo 2 3 ¢ Limestones minor siltstones shales dolomitic limestones. GARRA FORMATION rts Bas faq voruorag 4103 g 3 3 e g 5 3 3 e 2 > 2 5 g = z 2 3 2 s $ 2 = 2 2 5 (= = 3° Ee 5 2 2 oS ° ° o S = o 3 cs o a — = ro) Geological boundaries, accurate and inferred sf Strike ond dip AK Syncline , Anticline a Foult, position accurate — wedges ond arrows indicated direction of displacement where known a Foult — postuloted Roads major and minor ele--~ Creeks , doms Dwelling tA Meosured section FIGURE 1. ‘| measurement ‘| (Figure 2). THE GARRA FORMATION (EARLY DEVONIAN) AT WELLINGTON, N.S.W. Garra Formation The above, essentially volcanic unit (approx. 200 metres), is overlain by 30-50 metres of polymictic conglomerates, siltstones and shales, compositionally consistent with derivation from earlier erupted lavas. These sediments are best exposed in deeply weathered, discontinuous outcrops along Bracken Creek. The conglom- erate has well rounded clasts, imbricated in part, in a claret coloured siltstone matrix. Alter- nating siltstones and shales overlie the con- glomerate; these grade into approximately 10 metres of fine silty shales with discontinuous, thin, contorted laminae of limestone and several recessive biostromes composed of abundant rugose and tabulate corals, stromatoporoids and | crinoid columnals, with interstitial mudstone. The first laterally persistent limestone bed of the Garra Formation occurs approximately two metres above the highest of these biostromes. Definition of the top of the Cuga Burga -Volcanics and the base of the Garra Formation is open to variant interpretation. The cessation of vulcanism and subsequent deposition of detritus from the reworked lavas and tuffs in an apparently transgressive sequence of basal conglomerate, siltstone, shale, limestone, may be regarded as either representing the close of “Cuga Burga ’ or the commencement of ‘ Garra’ events ; the latter is suggested here. Formal naming of this member has been deferred pending accumulation of data over a wider area. The appearance of marine biota and the transition to a carbonate sequence indicates an important change in depositional environment ; this horizon has been used as the base for of the stratigraphic column As both the conglomerate and biostromes outcrop very poorly, the first laterally persistent limestone bed has been used, for the purposes of mapping (Figure 1), as an approximation to the base of the Garra Form- ation. Strusz (1965a), in describing the Garra Formation, estimated its thickness to be between 915 and 1,200 metres, but due to sporadic outcrop, rapid facies changes, thickness variations and an apparent absence of a complete sequence at any locality, did not propose formal subdivision. It is here suggested that a complete sequence is developed in the Wellington | Caves area. Within the mapped area, five sections were | measured (see locations Figure 1) ; close litho- | logical and faunal correlation has enabled | compilation of a stratigraphic column (Figure 2). is correlation demonstrates that faulting ‘ 113 and/or folding has caused offsetting and some apparent increases in thickness between the marker horizons—Units 11 and 18 of Figure 2. The composite section is nevertheless con- sidered to be complete (cf. Strusz 1965a) ; there are 970 metres of carbonates in this area, but an additional 45 metres occurs in outcrops 2-5 km to the north of Section E on the west bank of the Bell River. Still younger units eroded from the area in post-Praguian, pre-Fasnian times, prior to the onset of deposition of the Catombal Group arenites, may occur elsewhere. Within the western part of the area distinctive horizons, especially the biostromes, may be mapped and correlated with confidence and thus the sequence has been informally subdivided into 20 units based on lithological, sedimento- logical and faunal data. Analysis of the nature, composition, grain size and structures of the sediments and the aspect of the autochthonous fauna has enabled the depositional environment of each unit to be inferred (Figure 3). The depositional history of the Garra Formation in this area may be summarized as follows : 1. Initial transgressive phase ; reworking of volcanics ; onset of carbonate deposition and appearance of marine biota (Units 1-2). 2. Period of fluctuating, predominantly sub- tidal carbonate deposition on a shallow platform ; variable terrigenous influx con- tinues (Units 3-9). 3. Period of gradual carbonate build-up ; cessation of terrigenous influx; quiet environment with highly diverse fauna, shallowing and decreasing in diversity towards close (Units 10-11). 4. Development of sabkha-style, tidal and desiccated supratidal flats (Units 12-17). 5. Brief subtidal episode ; quiet environment with diverse fauna (Unit 18). 6. Further development of tidal and supratidal flats (Units 19-20). 7. Cessation of deposition ; uplift and erosion. Relationships in the eastern half of the area are difficult to determine as much of the lime- stone is massive and apparently marmorized ; almost all bedding, fossils and original textures have been lost. The boundary of this massive limestone may well be faulted, juxtaposing massive, structureless units characteristic of the upper part of the sequence against the well bedded lower units (e.g. in the Fault Wall of the Cathedral Cave). 114 BRIAN D. JOHNSON = = 5 He BR Se a re ° ° 3 2 aya i ee eet ey z See a er eee Be es z 2 1 3 ees z ene 2 SRS Ce S Se Be ee > <2 2 ~ 2 = Bf Poe a oS uw a = Ke LF] (te) he i (rh SY uit ee el: a . £ & BE Sire z rd fs Zs 3 2 3 Slee a Bo 2.3 £ SA $23 a A Be SG f= > a "ES a + 3 = . 2 is: Bae BL § 2 ates 3 3 | se : £s s 3 ae: * sss |2|] 12 [elses £3: | ehIS Sa Lhe TE ° Nene tu s £ 3 ea | iad : MP S ig = ———= +—— sajjaw 2 CP 2 z jiun ks fable é RS 13 = 2a s Bee | = 2 3 = f ire = ~, s s Ss, ¢ Ca || 5 2 = J > Sr wa 3 — = > 2 alte =~esis 3 5 | te : a} * 2 E2Bi° $ 3 2 ey tes Ble E ae 3 «E \ 2 4 8 E| 2 Beals Sree 2} £3 = Fig lit 6 a8 8lal < ci < ied 8 ranaCT Vv 2 ay : 2 4, z 2 irr e g 7) {Wl s i} g + ° & z Ener aes rs fat OS Ps 8 Beales e ‘ H os Pelee ae : zg eo s = eel) s| EO rE: | = Rey cles S = = ea A Wg Ci £ £ gfe /2s| cae t gs 2 segs |28| 8c" 3 3h * oo JAISSVW i 4 a 35 ih Section B THE GARRA FORMATION (EARLY DEVONIAN) AT WELLINGTON, N.S.W. 115 1500 m NORTH a Section E lovos ond tuffs Sholes B siltstones derived from volcanics Algae algal binding algal mots Volcanics = B Conglomerate derived from volcanics B=] Sondstones H “Birds eyes ”- disturbed muds with os Prat at D _sporry calcite infillings wd ’ ar oF) a= Dolomitic limestone OTHER LITHOLOGIES ES Colcareous shale = iv " — won. <3 e ae HRI i Corbonote cement Sted Sporry pore filling cements OTHER CARBONATES zee Silty limestone OTHER CHARACTERS rugese /crinold biostrome : #8 23 3 ee | 5 e 2 z 3 35 i g 3| 5 32 Bos Pak & ' 2 a ° $5 ee Tit 2 = e a a= = i , 3 peer pak grele eh s é a3 2 PS | = 26 3 Bios! 3 e $5 3 5 2 Nege #3 5 BS is 3/38 | £ 5 ie > 3 a = 5 £ = S<2 3 5 ales | cee ey eee ee ® 3 Ca =).i Bh Shee. s e Sethe als $2 3 s 3 z eit | 90 el emery ays 5 a £ & 3/8 33) 2 g z 3 « 2 ‘ ed ed ed ee Rae opel Pols 8 lire 3 | 2 | 5 s lel8| |gesltl* e= Bll 28 2 A 2/3] 6 5 : ic aie 2 iala| |B" elalp 22 Bl] 6s 5 é = & Ba &5| & F & 3 & a ae 3 S'slsle Sis &/|—s2—- s | ; a8 & @ ue taf ; ae LA Way Gus Ah Lea ate hat et ti Ty ee i ; uM il Section A A FIGURE 2. je} Section CORRELATION OF SECTIONS for location of sections see figure | Zi}: Section C pods, gastropods Stylolites ouno Abundont diverse brachiopods, founo Large bivolve,gastroped fcuna with red and yellow colcite Gostropods , brochiopods , crinoid debris Favosites , brachio| Stromotoporoids — Sparse GARRA FORMATION WELLINGTON CAVES AREA eo) — |5 mT o| & a 2 SSS 2) 5/ v/s a | | |Biolwlw) i] —f S| S| S| > | | e/ S/A\A/GIE|Sl5ls Seals in iz w| 2) of 4)4)< a eo} O}5 Le trees o o!5|2/c| sie Z2/SislVl=lisis 5/2 2 Si sl o| Li alge So Oo} ~ b= A f= =| Ma | c 8/8) 2/5] S] o> @oalolsl, |i hz z= ~ | a\ S| 2) ee] 2] Shalblal@2is ||| 7) 7 z re) UNIT oi%|x*)i =| Sie@ = a/Y}o}fZiie2 o/6 = 3/8/38] eS) sel staisial Sislells| Sle] 5 F =| FS] 21 S[ mo] SIP}-PP} of Ol e|= ol a] £1) ores aa | CL 19 = 18 iis i bom Ce ss 17 | ace [pasa] Ta 16 rama : a : f E BGHTERTEEYET: LBs aut i i : PO PEPCCOPEE TT Peo JOHNSON Limestones along the eastern flank of ‘ Camel- ford Ridge’ are marmorized and dolomitized but retain some of their primary character. | The outcrops to the volcanics in the south are rich in rugosans and crinoid debris, set in a redlt ferruginous calcite matrix ; these horizons may — be equivalent to the lowest units exposed in ~ Bracken Creek. Creamy dolomitic limestones with abundant rugose and tabulate corals occur in the north of this block. Breccias of limestone fragments in bright orange and red ‘ terra rossa ’ | are common. ; Limestone outcropping immediately beside and to the east of the Mitchell Highway have — been completely recrystallized and _ heavily veined with black and white calcite. =| _ S&S Ses ry eS Se eo — i a Age of the Garra Formation Correlation with northern hemisphere Early | Devonian sequences has been somewhat’ problematic (Strusz, 1967a). Druce (1970), on the basis of conodonts considered the Garra | Formation to be Middle Siegenian in its lower’ part. Combining this information with) information from corals and brachiopods, Strusz | (in Strusz e¢ al., 1972) considers the Garra) Formation as extending from the latest Loch- | kovian or earliest Praguian at the base, through Praguian, probably into Zlichovian. Additional support for the late Lochkovian— ~ early Praguian age of horizons low in the Garra | Formation comes from a conodont fauna from” the lowest bed of Unit 3 in Bracken Creek (base ” of Section A, Figure 2). The forms have been} kindly identified by Dr. G. C. O. Bischoff as: Belodella sp, Hindeodella priscilla, H. equidentata, Icriodus pesavis, Lonchodina detorta, L. crista- galli, L. greilingi, Neopriontodus bicurvatus, N. excavatus, N. cf. multiformis, Ozarkodina typica, O. denckmanm, O. media, Paltodus sp., Plectos-' pathodus flexuosus, P. extensus, Spathagnathodus| vemcheidensis, S. inclinatus wurmi, S. aff.: asymmetricus, Trichonodella excavata. (Slide No. MU 7277). Dr. Bischoff considers the age to be late Lochkovian-early Praguian. | A conodont fauna from Unit 11, 410 metres | above the base of the sequence (70 metres above} the base of Section B, Figure 2) includes the forms : Icriodus pesavis, Ozarkodina denckmanmi, i ae J . = at — ee — eo — e” SS FIGURE 3. (a) Dessication features :—‘ bird’s eyes ’, mud cracks, | algal mats, vadose silts ; for distribution of dolomites | see Figure 2. i (b) Discrimination of faunal aspect based on the generalization that brachiopods, corals, bryozoans,” crinoids, stromatoporoids were unable to survive subaerial desiccation in the intertidal zone. d | f oe << 1 | “| Spathagnathodus exiguus philipi, S. optimus, S. “}} sulcatus. (Slide No. MU 7278). Dr. Bischoff «| considers the age of this fauna to be early »)}| Praguian. Interestingly, the fauna includes ul} Spathagnathodus sulcatus and Icriodus pesavts, || Shown by Savage (1973a, b) as having mutually || exclusive ranges. nk Units higher than Unit 11 have so far failed }| to yield conodonts in the mapped area though ®|conodonts are abundant in samples from w)|roadside outcrops of dark grey, highly fossiliferous limestones underlain and overlain i)| by light grey massive algal limestones on the »|| Mitchell Highway 19 km NNE of Wellington j)) (the fauna and lithological sequence suggest +) probable correlation with Unit 18). Spathag- nathodus exiguus philipi, S. optimus, Ozarkodina denckmanni, O. typica australis, Plectospathodus extensus are prominent (Slide No. MU 7279) but in spite of quite high yields S. sulcatus and |i definitive younger forms such as S. exiguus exiguus or species of Polygnathus were not obtained. On the similarity of the conodont faunas and regional relationships, I suggest correlation of .\the basal Garra Formation with the basal limestones of the Mandagery Park Formation (Savage, 1968, 1973a, b); the latter is inter- preted as a tongue of Garra extending out into the Cowra Trough. According to my analysis, previously listed coral, conodont and brachiopod faunas from the ..| Wellington area have come from the following i: horizons : ‘s|) Strusz, (19655, 1966, 1970) rugose corals, i) |Localities Cr 103, 106, BR?/200, BR#/214,=Unit iih}2t. Localities Cr 100, 94, 89, 111, 113, 1} |BR1/177 =Unit 18. Also assignable to this unit are localities i (Cr 1, 2, and 77, just outside the mapped area. oD F Druce, (1970) conodonts, Locality WC5=Unit “ \10. f ‘| Strusz, (in Strusz e¢ al., 1972) Brachiopods 0" |Locality Wellington Golf Course= Unit 10, 11 Unpublished details of Dr. Strusz’s sections i Jare given in his Ph.D. thesis (Strusz, 1963), (his lt (BR*—=Section B, BR?=Section D, BR!= ‘Section E). aii = 'Catombal Group The lowest units of the Catombal Group in the ai jarea are red to white, medium grained sandstones m (orthoquartzites) of the Brymedura Sandstone (Conolly, 1963). There is a marked angular discordance of strike between the Garra lime- _ Stones and Catombal clastics in the south of the 8 1048 I THE GARRA FORMATION (EARLY DEVONIAN) AT WELLINGTON, N.S.W. 117 area, the angle of discordance gradually decreasing northwards. There is no evidence of Middle Devonian sedimentation, either in the Wellington area or for that matter in central N.S.W. (Pickett, 1972). Structure The broad structure appears to be a much faulted, north-plunging anticline. The western limb of the antiform is well preserved in uniformly dipping, well bedded limestones. The boundary of the marmorized limestones angularly transgresses the strike of the well bedded limestones and may be a fault. Many of the boundaries between volcanics and limestone could be faulted but this cannot be determined with certainty due to poor outcrops ; an unfaulted boundary nevertheless occurs in Bracken Creek. Small tight minor folds are common in the basal limestone units (i.e. near the Cuga Burga Volcanics) but are absent from the remainder of the sequence. Evidence of faulting has been inferred from the measured sections more often than from direct field observation. Faulting prior to deposition of the Catombal Group produced a number of fault slices causing offsetting ; either faulting or undetected folding has increased the apparent thicknesses (Figure 1) between the distinctive biostromes and in addition has resulted in minor discordances in strike direction between sequences in the blocks. The difference in orientation between basal sediments of the Catombal Group and the Garra Formation indicates that in this area the Garra Formation was dipping at about 15° north- easterly when deposition of the Catombal Group commenced ; this is evidence for mild tectonism and erosion having occurred during the Middle Devonian. Following the cessation of deposition of the Catombal Group, the region underwent major deformation, presumably during the Carboniferous. Acknowledgements I am indebted to Dr. John A. Talent for supervision of the project and to him and Dr. D. L. Strusz and Dr. C. McA. Powell for criticism of the manuscript; to Dr. G. C. O. Bischoff for identifying and dating the conodont faunas, and to Mr. Dean Oliver for drafting the diagrams under the supervision of Mr. Rod Bashford. Addendum The stratigraphic position of limestones along the eastern flank of Camelford Ridge is currently 118 under review ; conodonts recently discovered indicate a pre-Garra age. A paper discussing these findings and their significance is in preparation. References ADRIAN, J., 1971. Stratigraphic Units in the Molong District, New South Wales. Rec. Geol. Swyrv. N.S.W., 13 (4), 179. Conotty, J. R., 1963. Upper Devonian Stratigraphy and Sedimentation in the Wellington-Molong District, N.S:W.. J: Proc. Roy. Soc. (N.S.W,, 96, 73. Druce, E. C., 1970. Conodonts of the Garra Formation (Lower Devonian), N.S.W. Bull. Bur. Min. Res., Geol. Geophys., 116, 29. Kuaprer, G., 1969. Lower Devonian Conodont Sequence, Royal Creek, Yukon Territory, and Devon Island, Canada. J. Paleontology, 43, 1. OFFENBURG, A. C., RosE, D. M., PackHam, G. H., 1968. 1: 250,000 Geological Series, Sheet SI-55—4 Dubbo, N.S.W. Geol. Surv. N.S.W. Pickett, J. W., 1972. Correlation of the Middle Devonian Formations of Australia. J. Geol. Soc. Aust., 18, 457. Roserts, J., et al., 1972. Devonian Rocks of Australia. Correlation of the Upper J. Geol. Soc. Aust., 18, 467. SavaAGE, N. M., 1968. The Geology of the Manildra District, N.S.W. J. Proc. Roy. Soc. N.S.W., 101, 159. School of Earth Sciences, Macquarie University, North Ryde, N.S.W., 2113. (Received 15.1.75) BRIAN D. JOHNSON , 1973a. Lower Devonian Conodonts from New South Wales. Palaeontology, 16, 307. , 1973b. Lower Devonian Biostratigraphic Correlation in Eastern Australia and Western — North America. Lethaia, 5, 341. Strusz, D. L., 1960. The Geology of the Parish of | Mumbil, near Wellington, N.S.W. J. Proc. Roy. | Soc. N.S. W., 93, 127. 1963. Studies in the Palaeontology, Petro-— graphy and Stratigraphy of the Garra Beds. © Unpubl. Ph.D. thesis, University of Sydney. , 1965a. A Note on the Stratigraphy of the © Devonian Garra Beds of N.S.W. J. Proc. Roy. © Soc. N.S.W., 98, 85. , 1965. from the Devonian Garra Formation of N.S.W. Palaeontology, 8, 518. , 1966. Spongophyllidae from the Devonian i Garra Formation of N.S.W. Palaeontology, 9, 544. 1967a. Molong Geanticline, N.S.W., Australia. In: Oswald, D. H., (ed.). International Symposium on the Devonian System. Vol. 2, 123. Alberta © Society of Petroleum Geologists, Calgary, Canada, 1967b. of N.S.W. Palaeontology, 10, 426. , et al., 1972. Correlation of the Lower Devonian Rocks of Australia. J. Geol. Soc. Aust., 18, 427. , and ~JREE, 9. o:, (Radiophyllum) from the Devonian of Eastern Australia. Bull. Bur. Min. Resour. Geol. Geophys. Aust., 116, (Palaeont. Pap. 1968), 119. Disphyllidae and Phacellophyllidae Lower and Middle Devonian of the { Chlamydophyllum, Iowaphyllum and | Sinospongophyllum (Rugosa) from the Devon 1970. Cyathophyllum © Hydrothermal Ca-Al Silicates in Ophiolitic Rocks Near Coolac, N.S.W. H. G. GoLpInG AND A. S. Ray ABsTRACT—The modes of occurrence and diagnostic properties of hydrothermal grossular, chrome grossular, vesuvianite, prehnite and monoclinic and orthorhombic epidote minerals, from Coolac ophiolites are described. The Fe content of the prehnite and chemical analyses of zoisite concentrates, are reported. Differential thermograms of the Coolac vesuvianite and prehnite differ from those of the same minerals from other geologic environments. A distinctive habit of zoisite is recorded. Most of the observed garnet and vesuvianite occur in rodingitic enclosures within serpentinized peridotite. The prehnite and most of the zoisite occur in segregations at junctions of ultramafic with other rocks. The formation of these minerals may partly pre-date emplacement of the ophiolites at a continent margin. Additionally, the mineral sequence : epidote—clinozoisite— orthorhombic epidote group minerals—grossular and/or vesuvianite apparently registers increasing stratigraphic depth in the mafic part of the ophiolite suite and may indicate sub-sea-floor meta- morphism. Introduction Occurrences of hydrothermal _ garnet, vesuvianite, prehnite and minerals of the epidote group in the Coolac ultramafic belt were briefly noted by Golding (1969, 1971). The purpose of this paper is to record new data on these minerals from occurrences in the Mt. Lightning—Mooney Mooney Range sector of the belt. A sheet of serpentinized harzburgite dips steeply eastward throughout the sector. In the Mooney Mooney Range the harzburgite is flanked on the west by Successive masses of pyroxenitic, gabbroic and basaltic rocks or by mafic rocks and serpentinite. Brown (1973) additionally delineated a zone of predominant keratophyre (Figure 1). The authors regard this rock succession as an ophiolite sequence in which the harzburgitic member forms the stratigraphic base. The distribution of the hydrothermal minerals with respect to this proposed sequence is considered. The minerals under review commonly occur as fine-grained aggregates in which, although one phase may predominate, several phases are intimately admixed and some are poorly crystallized. These features hamper optical study and the preparation of material for chemical analyses, and in some instances result in broad X-ray reflections. The application of combined techniques, however, yields diagnostic data. Field work was shared by both authors. The senior author (H.G.G.) is responsible for most of the petrography, the second author (A.S.R.) for the X-ray and chemical analyses except where otherwise acknowledged. Modes of Occurrence The investigated minerals tend to occur in specific sub-environments as follows : Gp. 1 rodingites: Tabular bodies, 1-15 m long and <1 m wide, with characteristic jointing (Plate I, A) completely enclosed within serpentinite or partly serpentinized harzburgite along North and Central Mooney Ridges (Figure 1) and at Mt. Lightning (Figure 2). The constituents are garnet and/or vesuvianite + chlorite + diopside + minor tremolite. Relict undeformed microtextures indicate a gabbroic or doleritic precursor for some examples, but are commonly lacking. Garnetite and vesuvianite rock are essentially monomineral variants of the group. Gp. 2 rodingites: Diverse rocks, including segregations of zoisite and of prehnite up to 1 m wide, at junctions of serpentinized harzbur- gite and variolitic spilite at Haystack Creek, Mt. Lightning (Figure 2). Associated rocks include gneissic garnet-chlorite rock, trondh- jemite, albitite and tremolite rock. Northern zoisitites: Apparently independent masses of zoisite-rich rock encountered as blocks, 10-20 cm wide, and similar material completely replacing feldspars, 3-4 cm wide, in gabbro pegmatite. Both occur at or close to the junction of clinopyroxenite and gabbro at North Mooney Ridge (Figure 1). Easterly reaction selvedges : Sporadic tabular masses, ~50 cm wide, of prehnite-+garnet at junctions of harzburgite and granodiorite along South Mooney Ridge (Figure 1). NORTH MOONEY RIDGE 7 CENTRAL MOONEY RIDGE\ MT. LIGHTNING 4 Figure 1.—Sketch map of the north of the Coolac ultramafic belt showing principal lithologic sub- divisions. : Silurian volcanic and sedimentary rocks. : Keratophyres. : Basalts and metabasalts with some serpentinite. : Gabbros and metagabbros. : Clinopyroxenite and wehlite. : Harzburgite and serpentinite. : Silurian granodiorite. “OO r WNW Veinlets in ultramafic rocks : Mainly of Gp. 1 rodingite, garnet or vesuvianite, in chromitite, at Mt. Lightning. Other sub-environments : Keratophyres, metabasites and associated epidosite veins flanking harzburgite in the Mooney Mooney Range (Figure 1) and at Mt. Lightning (Figure 2) and sporadic lenses of albitite and trondhjemite in harzburgite or serpentinite. The hydro- thermal Ca-Al silicates are principally members of the epidote group. Micro-veinlets of prehnite additionally occur in some albitite. Garnet Garnet-rich portions of Gp. 1 rodingites, and garnetites (70 to 95% garnet), are finely granular H. G. GOLDING anp A. S. RAY to dense, and white or pale grey in hand specimens. Thin sections reveal aggregates of moderately clear, colourless, polygonal grains, 0-1 to 0-3 mm wide, which are optically isotropic, or more commonly, pale brown turbid aggregates in which the grain boundaries are indistinct. In the turbid material isotropism is modified by milky internal reflections due to dispersed impurities. Garnet euhedra are uncommon bu the crystal form is expressed against chlorite. In gneissic Gp. 2 rodingites, augen of granular garnet are aligned within a matrix of chlorite. Much Coolac garnet appears to have crystallized froma paste. This is inferred from the dispersed impurities, turbid cores to numerous grains, variable crystallinity, relict colloform texture (Plate I, B) and (?) dehydration pores lined with chlorite Plate I, C). Chrome garnet, emerald green in thin section is associated with chlorite in veinlets penetrating chromite. The grains are commonly zoned (Plate II, A). In some grains there is a chromite core, a median zone of green isotropic garnet and a rim of pale pink, anisotropic garnet. Wider veins of colourless garnet in chromite display a selvedge of green garnet at contacts with chromite. The terminology for garnets used in this paper follows Deer e¢ al. (1962a). These and other authors have recorded hydrogrossular as ¢ constituent of rodingite. Hydrogrossular, member of the series 3Ca0.A],0,.3Si0; 3CaO.A1,03.6H,O, exhibits decreasing refractive index and increasing cell size with increasing substitution of Si by 4H. Provided that no significant substitution of Ca?+ by Fe?+, Mg?™ or Mn?+ or of Al§+ by Fe%+ has occurred the position of a garnet in the series may be estimated from the curves of Hutton (1943) ane¢ Yoder (1950). On this basis data obtained from very small sub-samples of clear Coola garnet (Samples 3, 5, 6, 7; Table 1) suggest ¢ composition close to that of anhydrous grossulai but the material tested may not be rep resentative. Dispersed impurity, approaching vesuvianite in composition, may be responsible for the low-index material (Zabinsky, 1964) it Samples 2, 4 and 5 (Table 1). Differential thermal curves of Coola garnetites containing <10% of chlorite o vesuvianite lack peaks (Figure 3). Thermo grams of strongly hydrous grossulars ar reported to show endothermic peaks at 650: 690°C and exothermic peaks at 870° and 940°C (Deer et al., 1962a). A moderately hydrous grossular from South Africa exhibits a endothermic reaction at ~1100°C but tht HYDROTHERMAL Ca-Al SILICATES IN OPHIOLITIC ROCKS PEE EERE EE EEE EEE PEE EEE EEE tt tt ttt ttt SPEER EEE EEE EEE ESE Et tet ttt tt ttt ttt tt SEES EEE EE EEE SEE EE EEE ett ttt ttt ttt ttt hess ASRS Stet tttttt+ tr,.. $tttttt+ SEES SESS t tt ttt tte ttt thtet $Ftttttsttttetti yy Shh hhtttteett ed $$h$hte44444444 LIGHTNING ® x oc ¥ QUILTE Re. : WEST LAMATTA AN ttttt+++++5 BLOCKY SERPENTINITE AND HARZBURGITE SHALE, CHERT GREYWACKE RODINGITE LOCALITY O Be | O oc < > ‘SPICAIT-E $+4444 +$+4444 +$+4444 GRANODIORITE SERPENTINITE SHEARED AN CHROMITE MINE ROAD FiGuRE 2.—Geo'ogical sketch map of Mt. Lightning. ® 122 curve begins to descend at ~1080°C (Frankel, 1959). There is no indication of this reaction in the low index Coolac material (Sample 2). These data tend to confirm the view that the non-chromiferous Coolac garnets are variably crystallized, impure grossulars and/or only slightly hydrous grossulars. H. G. GOLDING anp A. S. RAY colours but in some specimens shows normal low first order polarization colours. In some specimens the mineral is uniaxial, in others it is biaxial. Lamellar twins and patchy zoning are common. In rare veinlets the vesuvianite crystals are 1 mm wide and enclose garnet crystals 0-1 mm wide. TABLE 1 Data on Garnets from Mt. Lightning. Sample Location Host Material n aA +0:002 | +0-005 1 Quilters East White Gp. 1 garnetite (D=3-37). Garnet (90%) + 1-734 — chlorite 2 Quilters East White chert-like patches (D=3-39) of dense, impure 1-693- —- garnet in rodingite-serpentine breccia 1-700 3 Above Haystack Creek | Pink and green Gp. 1 rodingite. Garnet (60%), 1-733 11-855 vesuvianite (20%) + diopside 4 Haystack Creek Mottled grey and cream Gp. 2 rodingite. Garnet 1-723- 11-860 (85%), zoisite (10%) +sphene 1-726 5 Haystack Creek Pink and grey gneissic Gp. 2 rodingite. Garnet 1-734 11-862 (60%), chlorite (20%) + -zoisite (clear) + 1-699 (turbid) 6 East Ellamatta Creek | Pinkish-white Gp. 1 garnetite. Garnet (90%)+ 1-732- 11-853 chlorite 1-733 11-849 7 East Ellamatta Creek | As Sample 6. Garnetite with relict colloform texture 1-730 11-856 1-729 11-851 1-732 11-854 8 Quilters West Veinlets of zoned garnet+chlorite in chromite *1-82 — (green) 1-79 (pink) = *+0-01. Vesuvianite Vesuvianite commonly forms patches, streaks and veinlets surrounded by grossular and chlorite. The ratio of vesuvianite to grossular increases toward the centres of some Gp. 1 rodingite bodies. In other Gp. 1 rodingite bodies vesuvianite occurs to the exclusion of grossular. Some vesuvianite-rich rodingites (up to 95% vesuvianite) are megascopically pink and finely saccharoidal, others are brownish grey, brittle rocks with greasy lustre and conchoidal fracture. The pink variety is common in chromite-rodingite breccia. Megascopically pale green vesuvianite forms rare veinlets in some chromitite. Thin sections of vesuvianite-rich rodingite reveal aggregates of polygonal and rectangular grains. The grains, up to 0-5 mm wide, are euhedral against chlorite and less turbid than most grossular. The vesuvianite commonly shows anomalous yellow and brown polarization The refractive indices, cell sizes and D.T.A. data for selected examples of Coolac vesuvianite — have been compared (Table 2) with samples collected by one of the authors (H.G.G.) from — other ophiolite environments. According to Troger (1956) w<1-720 indicates <5% TiO,+ Fe,O,+FeO but data in Deer e al. (1962a) show some departures from this rule. Maximum indices of Coolac vesuvianites do not exceed — 1-717, but vesuvianites from Chrome Hill, Nundle and Radusa, Macedonia (Table 2) register higher indices, and a value of 1-729 was recorded by Miles (1950) for vesuvianite from Eulaminna, Western Australia. The extensive possibilities for ionic substitution in vesuvianites (Ito and Arem, 1970) preclude simple correlations between optics, cell dimensions and compositions for the group as a — There is a suggestion (Table 2), however, § whole. that the higher index vesuvianites from Chrome Hill and Radusa have the smaller cell dimensions. = =<. = 2 = CO | Bas | f | r HYDROTHERMAL Ca-Al SILICATES IN OPHIOLITIC ROCKS Differential thermograms of the Coolac vesuvianites show a characteristic endothermic peak at ~1050°C. Continued heating gives an exothermic peak at ~1090°C (Figure 3). According to Peters (1961) the first reaction registers lattice disruption and dehydration, the second reaction registers recrystallization to | Bac §7OO ~ 800 900" 1000 “Oo'c | Ficure 3.—Differential thermograms (600-1,100°) of garnetiferous and vesuvianite-rich materials. : Garnetite (Sample 6, Table 1). : Chert-like garnetite (Sample 2, Table 1). : Vesuvianite rock (Sample 1, Table 2). ; Vesuvianite-rich rodingite (Sample 2, Table 2). : Gp. 1 rodingite containing grossular, vesuvianite, chlorite and pyroxene, Ellamatta Creek, Mt. Lightning. ' F: Vesuvianite-bearing vein material, Radusa (Sample 8, Table 2). G: Brown vesuvianite from calc-silicate rock, near Marulan, N.S.W. leo @ lov garnet, melilite and doubtful anorthite. The thermal behaviour of the Coolac samples accords with that of vesuvianite from the Totalp-Serpentinmasse, near Davos, Switzerland (Peters, ibid.). The Chrome Hill and Radusa material react at slightly lower temperatures possibly due to the presence of admixed phases. Brown vesuvianite from a contact metamorphic 123 aureole near Marulan, N.S.W., tested for comparison, and vesuvianite from Vesuvius (Peters, «bid.), exhibit distinctly lower temperature endothermic reactions (Figure 3). The low refringence and the refractory thermal behaviour of the ophiolitic vesuvianite, particularly the Coolac samples, may indicate a relative deficiency of Fe and Ti, volatiles or other constituents. Patches of vesuvianite in a matrix of grossular may indicate compositional variations from domain to domain in the original rocks. Veinlets of vesuvianite, and vesuvianite-rich centres of rodingite bodies, possibly delineate the passage of late magmatic fluids. Prehnite Prehnite is a minor constituent of the northern zoisitites but forms prehnitites (70 to >95% prehnite) at Haystack Creek and at peridotite- granodiorite contacts. The prehnitites are of medium grain size (0-5-2-0 mm) but appear to be porcellanous in hand specimens. Most are white and massive, but grey bands of chlorite+ sphene occur in some samples and grey or cream-coloured zoisitic patches occur in others. Interstitial prehnite in the northern zoisitites is pellucid but most prehnite is slightly turbid. Euhedra are absent. Grain aggregates exhibit diverse textures which include radiating, banded columnar, polygonal granular (? columns viewed transversely) and sutured (Plate II, B). The grains show two cleavages, normal second order polarization colours and pronounced undulose or mosaic extinction. Coleman (1961) noted that the distinction of fine-grained prehnite and pectolite may be uncertain if based solely on refractive indices and strong X-ray reflections. The relatively coarse-grained textures of the Coolac prehnitites and other prehnite-bearing rocks, however, are usually diagnostic and optical and X-ray powder determinations have been confirmed by D.T.A. and a partial chemical analysis of one of the Haystack Creek prehnitites. The latter, estimated to contain <5°% impurities (zoisite, chlorite and sphene), was analysed by Dr. P. Bayliss, using atomic absorption spectroscopy and gave the following wt% values : SiO, : 44-0, Al,O, : 23-5, CaO: 24-7 and H,O: 4-6 (Sub- total : 96-8%). The D.T.A. of the Coolac prehnite accords with that reported for prehnite by McLaughlin (1957). The curve shows double endothermic peaks corresponding to dehydration in two stages at ~780° and ~870°+20°C (Figure 4) and is usually diagnostic despite considerable 124 variation in the position and intensity of the two peaks depending mainly on the amounts and kinds of other phases present. The presence of substantial chlorite, however, is confusing. In view of the occurrence of prehnite and zoisite in various proportions in chlorite-poor Gp. 2 rodingites at Haystack Creek, reference curves for artificially prepared mixtures of the two minerals in the proportions 3:1, 1:1 and 1:3 have been compared (Figure 4). A thermogram of deuteric prehnite from the Prospect alkali dolerite intrusion near Sydney, H. G. GOLDING anp A. S. RAY 1-640+0-002 (av: 1-638) and g=1-613- 1-614+0-002 (av: 1-614). These values © indicate a low Fe content. Determinations of Fe by means of wet chemical and X.R.F. methods gave values for total Fe as Fe,O, from — 0-2 to 0-3 wt% in Haystack Creek prehnitites. Most prehnites from diverse geologic environ- it } | ! | I 4 ments apparently contain <10 mole per cent of — the ferrian end-member (Hashimoto, 7bid.) but $ electron probe studies of prehnite from rocks in ; the prehnite-pumpellyite metagreywacke facies (Surdam, 1969) and from a contact metamorphic TABLE 2 Data on Vesuvianite from the Mooney Mooney Range (Samples 1, 2), Mt. Lightning (Samples 3-6) and from Other Ophiolites Samples 7, 8). Cell Edge D.T.A. n A Sample Locality Host Material Cc +0-002 | a+0-005— c+0:-01 1 North Mooney Ridge Pink vesuvianite rock in chromite- | *En 1050 ¢ 1-712 — rodingite breccia Ex 1090 @ 1-715 2 Central Mooney Ridge | Grey Gp. 1 rodingite containing 80% En 1050 — — vesuvianite which shows normal Ex 1090 polarization colours 3 Quilters South Brownish grey, Gp. 1 rodingite con- En 1050 min 1-710 15-595 taining 95% vesuvianite which is | Ex 1085 max 1-716 11-80 biaxial 4 Upper Haystack Creek | Vein of vesuvianite in garnetized En > 1030 == 15-602 dolerite 11-85 5 Ellamatta Creek Centre of Gp. 1 rodingite. Vesu- Chlorite — _ vianite (30%), grossular (30%) peaks + +chlorite + diopside En 1041 Ex 1075 6 Quilters East Vein of green biaxial vesuvianite in — min 1-713 15-590 chromite max 1-717 11-84 ui Chrome Hill, Nundle Vein of green vesuvianite + grossular En >1020 | max 1-720 15-570 in serpentinite 11-84 8 Radusa, Macedonia Vein of green vesuvianite + diopside + En >1015 | max 1-721 15-583 grossular in rodingite 11-84 * En: Endothermic peak. Ex: Exothermic peak. obtained for comparison, differs notably from environment (Robinson, 1973) show these that of the Coolac prehnite but accords with that reported for prehnite elsewhere by Norin (see Deer et al., 1962b). The two patterns of thermal behaviour may indicate two structural varieties of the mineral. Prehnite is regarded as a solid solution of ideal aluminian and ferrian end-members : Ca,Al],Sis0;)(0H), and CagF ez” Sig019(OH), respectively. The refractive indices increase with increasing substitution of Fe%+ for Al*+ (Tréger, 1956 ; Hashimoto, 1964) and y<1-640 indicates Al prehnite (<1-5 mole per cent of the ferrian end-member, and <1-0 wt% Fe,0s). Refractive indices of prehnites from three occurrences at Haystack Creek are y=1-637— prehnites to be highly variable with some grains containing up to 30 mole per cent of the ferrian end-member. Similar studies are desirable for the Coolac prehnites but the mineral in the Haystack Creek uniformly Fe-poor. sub-environment may be An occurrence of zoisite replaced by veinlets of prehnite in Newfoundland (Watson, 1942) may imply that prehnite is related retrogressively to zoisite (Liou, 1971 ; Holdaway, 1972). prehnite occupies spaces between uin-replaced © zoisite euhedra (Plate II, C). One of the Haystack Creek rocks contains prehnite pseudomorphs of zoisite crystals but in most of © the prehnite-zoisite associations near Coolac the | | | i{ i Leal | | | | | lh ore joriews ak ae LS LT TE ET TT Pee Ie SN ew ere eae aes ~ Ss ai a: ¥ ae HYDROTHERMAL Ca-Al SILICATES IN OPHIOLITIC ROCKS lIOOO 600 700 800 900 NOO°C Ficure 4.—Differential thermograms (600-1,100°C) of prehnite-rich, zoisite-rich and related materials. A: Zoisitite (> 95% zoisite), Haystack Creek. B: Prehnitite (>95% prehnite+a little Haystack Creek. C, D, E: Mixtures of A and B in the respective proportions 3:1, 1:land1: 3. F : Prehnite from the Prospect Intrusion, N.S.W. G:Green epidote from the Harts Range, Central Australia. zoisite), Epidote Minerals Terminology and Identification The Al-Fe epidote minerals may be referred to a series with the ideal end-members Ca,Al,Si,0,.(0OH) or zoisite (Ps) and Ca,Fe3*Si,0,,(OH) or pistacite (Psy). They “may also be conveniently subdivided into two orthorhombic groups: zoisite (Psy_».;) and ferrian zoisite (Ps,.,_;) and two monoclinic | groups : clinozoisite (Ps; _,,) and epidote (Ps,o_35) (see Deer et al., 1962a ; Holdaway, 1972). In the present study orthorhombic members have been distinguished from monoclinic members using the X-ray criteria of Seki (1959), zoisite has been distinguished from ferrian zoisite on the basis of optics and Fe content (Myer, 1966), and epidote has been arbitrarily distinguished from clinozoisite on the basis of colour and pleochroism. 125 Because intimate intergrowths of epidote minerals have been frequently reported elsewhere (see Ackermand and Raase, 1973) X-ray powder patterns of samples have been checked for the possible presence of both orthorhombic and monoclinic members. The diagnostic X-ray reflections for the zoisites (absent for clinozoisite) are at d=3-67, 3°62, 3-15, 3-08, 2-72 and 2-33 A, and those for clinozoisite (absent for zoisite and ferrian zoisite) at d=3-47, 3-40, 3:20, 2-59, 2-45, 2:16 and.1-57 A. The absence of X-ray reflections for vesuvianite which, in some of its occurrences, resembles zoisite in thin section, was also checked. Myer (1966) drew attention to the widespread confusion of terminology for the orthorhombic epidote minerals, and proposed that the terms a-zoisite and (-zoisite be discarded in favour of ferrian zoisite and zoisite respectively. Myer distinguished zoisite with up to 0-14 atoms of Fe*+ (on the basis of 25 oxygens), O.A.P. | to the cleavage (100) and dispersion r>v from ferrian zoisite with >0-14 atoms of Fe®+, O.A.P. || cleavage (100) and dispersionr1-3 wt% indicate ferrian zoisite. In several Coolac samples Fe content inferred from the optics of selected grains has been confirmed by bulk chemical analyses of concentrates (Table 3) by means of X-ray fluorescent spectrometry. Because some epidote minerals retain hydroxyl after heating at 1,000°C (Deer et al., ibid.), the loss on ignition of analysed zoisite concentrates was determined at 1,400°C. A_ repeat determination made at 1,000°C on one sample, and consistent strong endothermic peaks at 975°+15°C in differential thermograms (Figure 4), however, suggest that heating at 1,000°C may in fact suffice for the determination of water in Fe-poor zoisite. No reference to the D.T.A. of zoisite was encountered in the literature but the dry decomposition of zoisite to a mixture of anorthite, gehlenite and pseudowollastonite at or above 810°C is reported by Deer et al. (ibid.). Differential thermograms of clinozoisite-rich material from Mooney Mooney Range epidosites are similar to those of analysed zoisite concentrates. Zoisite and clinozoisite therefore cannot be distinguished by D.T.A. Once zoisite has been determined by other methods, however, the D.T.A. curve provides a useful guide to the proportions of phases present, at least in zoisite-prehnite assemblages. A 126 thermogram of green epidote from the Harts Range, Central Australia, tested for comparison, exhibits a weak endothermic peak at ~975°C followed by a stronger peak at ~1,015°C (Figure 4) suggesting water loss in two stages. The second peak accords with that for epidote recorded by McLaughlin (1967). Zoisite At North Mooney Ridge zoisitite contains zoisite (70-80%)-+diopside and _prehnite. Similar material in the gabbro pegmatite contains zoisite (70-80% )+grossular and prehnite. At Haystack Creek zoisitites con- tributing to Gp. 2 rodingites contain zoisite (60-95%) +-prehnite, chlorite, albite and sphene. Hand specimens of these rocks are pink to pale grey and commonly indistinguishable from some Gp. 1 rodingites. In the best-crystallized material the zoisite forms felted aggregates of decussate, euhedral crystals up to 1:0x0°5x 0-2 mm with a tabular, bladed habit. Prehnite, chlorite or grossular occupies the interstices. In some Haystack Creek specimens zoisite forms turbid masses of interlaced prisms or plumose acicular aggregates. Diffractograms confirm the presence of orthorhombic members of the epidote group, and the absence of monoclinic members, in all these segregations. The habit of the well-crystallized zoisite (Figure 5 ; Plate II, C) results in three principal kinds of grain sections: (i) narrow, elongate, length-fast sections || cleavage (100), (11) broader plates || (001) giving Bx, interference figures and showing length-slow cleavage traces and (iii) doubly terminated, length-fast sections || O.A.P. (010). This distinctive habit and optic orientation is not described in texts available to the authors, but doubly terminated sections are known in metamorphic rocks (e.g. Joplin, 1968, p. 206). The optic orientation indicates zoisite as distinct from ferrian zoisite. All the segregated Coolac zoisite displays normal low first order interference colours, and lacks zoning and multiple twins. Cross fractures are common in all elongated sections irrespective of orientation. Other optical data and chemical analyses of zoisite concentrates (Table 3) preclude the presence of significant amounts of ferrian zoisite in the segregations. Epidote Minerals in the Ophiolite Sequence Green epidote forms micro-veinlets comprising 5-15°% of the rock in quartz keratophyres of the Mooney Mooney Range and accompanies clinozoisite in metabasalts flanking Mt. Lightning on the west. Colourless clinozoisite is the H. G. GOLDING anv A. S. RAY common epidote mineral in metabasalts and metagabbros of the Mooney Mooney Range. The metabasalts contain variable amounts of actinolite, — calcic plagioclase, albite, chlorite and _ clinozoisite. augite, The metagabbros contain variable amounts of calcic plagioclase, — saussurite, albite, augite, hornblende, actinolite, — clinozoisite and are — veined by epidosites containing predominant — The veins, ~1 cm wide, are pink © tremolite, chlorite and clinozoisite. and finely saccharoidal in appearance. They sharply penetrate or merge with the metagabbros that are mottled pink and green. Ficure 5.—Habit and optic orientation of zoisite from segregations at North Mooney Ridge and Haystack Creek. The clinozoisite of the metagabbros and veins occurs in polygonal granular aggregates or clusters of prismatic crystals. Individual crystals attain a maximum width of 0:5 mm. Doubly terminated sections are absent. Most grain sections show anomalous polarization colours, blues predominating. Lamellar twins and patchy zoning are common. Grains with regular zoning occur in some specimens. This heterogeneity on the scale of vein widths, micro- domains and single grains is characteristic. Diffractograms indicate predominant clino- zoisite+minor amounts of zoisite or ferrian zoisite as revealed by weak reflections at d=3 -68 and d=8-15 A. P . abit Wa lees oy We ee a he OL re RE NE EE OE TR EY EOS VU IN URE EO FRE eS ee, a ee Re Serger =>. S23 2 Fe =e | i (2 — > i i § t Ss = FF Some metagabbros ~100 metres west of the harzburgite contain diopsidic augite, chlorite, grossular (10-20%), in some samples vesuvianite (5%), together with members of the epidote group (10-20%). Grossular, vesuvianite and epidote group minerals are segregated in respective micro-domains. The epidote group minerals display some doubly terminated sections, predominantly first order polarization colours, minor zoning and twins. The status of Creek, Mt. Lightning (Samples 2, 3 and 4). — 1 2 SiO, 39-84 39-67 a 0-07 0-07 Al,O, 31-85 32-67 *Fe,O, 0-69 0-44 MnO 0:02 0:07 MgO 1-79 0-70 CaO 23-40 23-29 K,O 0-01 0-15 PO, 0-13 0-31 So, 0-04 0:04 +Loss 3-30 3-60 }| . Total 101-14 101-01 On i . B+0-002 2V + (meas) Dispersion .. * Total Fe as Fe,O3. t Loss on ignition. ‘this material as zoisite, ferrian zoisite, a mixture of both, or of one or both of these with minor clinozoisite (see Ackermand and Raase, ibid.) thas not been determined. In the harzburgitic member of the rock association metabasites are represented ‘Principally by the enclosures of Gp. 1 rodingite which are devoid of minerals belonging to the epidote group. | A broad trend of variation in the secondary Ca-Al silicates from west to east across the i}} mafic-ultramafic association is suggested as ‘follows: green epidote—clinozoisite—orthor- if} hombic epidote group minerals—grossular and Vesuvianite. This trend is one of increasing ‘stratigraphic depth in the proposed ophiolite ‘Sequence (Figure 6). It may broadly reflect hydrothermal alteration of mafic rocks in ul | | HYDROTHERMAL Ca-Al SILICATES IN OPHIOLITIC ROCKS 2, 3 and 4 ~5% of Prehnite + Chlorite + Sphene+Albite. 1-695 42° I>v 127 conditions of increasing temperature and/or decreasing oxygen fugacity with increasing stratigraphic depth (see Coombs ef al., 1970; Holdaway, 1972; Liou, 1973) together with variations induced in proximity to ultramafic contacts. The influence of initial rock com- position, the proximity of some samples to former channels of enhanced fluid mobility or metasomatic activity, and other factors, also require consideration in future studies. TABLE 3 Chemical Analyses of Zoisite Concentrates from Segregations at North Mooney Ridge (Sample 1) and Haystack Impurities : Sample 1 contains ~10% of Diopside+ Prehnite. Samples Analyst: A. S. Ray. Formula of Sample 3 4 4 on the Basis of 25 (0) 39-40 39-85 Si 6-100) “15 0-09 P 0-037 }$6-137 32-79 31-54 Al — 0-39 0-43 Al 5-689 0-00 0-07 Fe 0-055 >5-753 0-33 0-83 Ti 0-009 23-02 23-36 0-55 0-15 Mn 0-009 0-16 0-31 Ca 3-837 0-01 0-04 Mg 0-184 }4-057 2-50 3-60 K 0-036 99-30 100-27 Optical Data 1-697 | 1-695 | 1-700 36° 33° 20° I>v — I>v Discussion Rodingite has been variously defined and interpreted (Coleman, 1967; Aumento and Loubat, 1971; Aumento, 1972; De, 1973; O’Brien and Rogers, 1973). The term has been used for diverse rocks the relationships of which to ophiolite sequences (Church, 1972; Page, 1972 ; Moores, 1973 ; and Gass and Smewing, 1973) require re-appraisal. An adequate description of the rodingitic rocks near Coolac must await studies of the complete mineral assemblages and of the petrochemistry of associated variants. Present observations, however, suggest that the qualifier “ rodingitic ” is appropriate for those members of the ophiolite suite that contain substantial amounts of relatively well-crystallized, Fe-poor, secondary Ca-Al silicates. Saussuritic rocks and most epidosites are thereby excluded. Near Coolac rodingitic rocks are characterized by grossular, vesuvianite, prehnite and “ zoisitic’’ minerals. Grossular may accompany each of the others, but intimate associations of prehnite and vesuvianite have not been encountered and associations of orthorhombic epidote minerals and vesuvianite are uncommon. Free silica and carbonates are absent from _ rodingitic assemblages except at junctions with trondhjemite, albitite or granodiorite. DACITE KERATOPHYRE BASALT AND METABASALT GABBRO AND METAGABBRO HARZBURGITE AND SERPENTINITE FiGURE 6.—Schematic ophiolite sequence in the Mooney Mooney Range showing trend in the distribution of the secondary Ca-Al silicates. Z: zoisitite. apa clinopyroxenite. amphibolite. R. Gp. 1 rodingite. F: proposed fault. Ep: enidote. Cz: clinozoisite. Zo: zoisite and/or terrian zoisite. Gr: grossular. Vs: vesuvianite. Pr: prehnite. The Coolac rodingitic rocks include a wide range of products that may have formed in different ways and at different times. For example, Gp. 1 rodingites apparently represent mafic dykes or pockets of trapped mafic magma. Metasomatism may have merged with the consolidation of some of these rocks but succeeded consolidation of others. Gp. 2 rodingites apparently belong to reaction zones H. G. GOLDING anp A. S. RAY (Coleman, 1967) that formed at junctions of } i! contrasted rock types. Zoisitized gabbro peg. matite may have been altered as a result o magmatic or external fluid attack or may have #}'! resulted from contact metamorphism that iil involved the recrystallization of saussurite ji (Olsen, 1961). & Several formerly problematic features of the rock association in the Mooney Mooney Range }}® may be interpreted as logical consequences of to ophiolite generation and modification accordi 5 to current concepts (Bonatti e¢ al., 1971; Aumento, 1972; Moores, 1973; Gass and Smewing, 1973; Spooner and Fyfe, 1973), | Ophiolites are regarded as segments of forme 7 sub-oceanic lithosphere generated at rifts | beneath oceans or marginal seas, modified b | faulting, intrusion, differentiation and complex © metamorphism that included hydrothermal | processes, prior to emplacement at margins 0 continents or island arcs. Bee _. io 7 The status of the rock association in the Mooney Mooney Range as a partly preserved ophiolite sequence is suggested by assemblage of features. These features include © (i) the tectonic setting between granodiorite and chert-bearing sedimentary and volcanic = rocks, (ii) a rock sequence ranging from deformed } harzburgite (with enclosures of podiform | chromitite, Gp. 1 rodingite and trondhjemite) | through essentially undeformed diopside-rich | cumulates or through amphibolite to altered gabbro, basalt and keratophyre, (iii) dive gabbroic rocks that are sporadically ed with epidosite,. (iv) basaltic rocks that exhibit a variety of relict igneous textures and a closely associated with serpentinite in sori areas, (v) metabasite assemblages that a similar to those of the greenschist, an transitional greenschist to amphibolite, facies of | metamorphism, (vi) mafic dykes and apophyses | displaying apparently conflicting age relation- | ships and (vil) a trend in the distribution of | hydrothermal Ca-Al silicates that may correlate | with “ sub-sea-floor metamorphism ” “ Sub-sea-floor metamorphism ”’ incorporates “ dynamothermal =e background - and | " ‘geothermal system metamorphism ” (Spooner | and Fyfe, 1973). Geothermal system metamor- phism involves the circulation of hot brines that become increasingly reducing with depth prior | to upward discharge. Such fluid circulation} may have promoted the formation and influenced | the variation of the epidote minerals and maj have induced some types of rodingitization. I might be conjectured that the rock association in the Mooney Mooney Range incorporates am) h $4 ti la HYDROTHERMAL Ca-Al SILICATES IN OPHIOLITIC ROCKS ophiolite sequence generated at a rift and an lintrusion, represented by the pyroxenite, that |was generated above a subduction zone (see |Stevens et al., 1974). Irrespective of such \conjectures, metasomatism doubtless occurred lat various times in the complex history of the jassociation and prehnite and grossular at peridotite-granodiorite contacts may have resulted from the post-emplacement passage of fluids that were meteoric in origin. ACKNOWLEDGEMENTS The authors thank Dr. P. Bayliss for the partial analysis of prehnite, Mr. G. Melville for drafting and Professor J. J. Frankel for helpful jsuggestions. References ACKERMAND, D., and Raasez, P., 1973. Coexisting Zoisite and Clinozoisite in Biotite Schists from the Hohe Tauern, Austria. Contry. Minerval and Petrol., 42, 333. AUMENTO, F., 1972. The Oceanic Crust of the Mid- Atlantic Ridge at 45°N., Jn Irving, E (Ed.), The Ancient Oceanic Lithosphere, Dpt. Energy, Mines, Res., Ottawa, 49. AUMENTO, F., and Lousat, H., 1971. The Mid- Atlantic Ridge near 45°N. XVI. Serpentinized Ultramafic Intrusions. Can. J. Earth Sci., 8, 631. Bonatti, E., HoNNoREZ, J., and FERRARA, G., 1971. Peridotite-Gabbro-Basalt Complex from the Equatorial Mid-Atlantic Ridge. Phil. Trans. Roy. ~ Soc. Lond. A, 268, 385. Brown, P., 1973. Ophiolites of the Central Mooney Mooney Ranges, a Portion of the Coolac-Goo- barragandra Ultramafic Belt, N.S.W. Hons. B.Sc. thesis, Univ. of N.S.W. (unpublished). Cuurcu, W. R., 1972. Ophiolite: its Definition, Origin as Oceanic Crust and Mode of Emplacement in Orogenic Belts, with Special Reference to the Appalachians, Jn Irving, E. (Ed.), The Ancient Oceanic Lithosphere, Dpt. Energy, Mines, Res., Ottawa, 71. CoLEMAN, R. G., 1961. Jadeite Deposits of the Clear Creek Area, New Idria District, San Benito County, California. J. Petrology, 2, 2. CoLEMAN, R. G., 1967. Low Temperature Reaction Zones and Alpine Ultramafic Rocks of California, Oregon and Washington. U.S. geol. Surv. Buil., 1247, 1. Coomps, D. S., Horopysk1, R. J., and Naytor, R. S., 1970. Occurrence of Prehnite-Pumpellyite Facies Metamorphism in Northern Maine. Am. J. Scz., 268, 142. Dr, A., 1972. Petrology of Dikes Emplaced in the Ultramafic Rocks of Southeastern Quebec and Origin of Rodingite. Geol. Soc. Amer. Mem., 132, 489. Derr, W. A., Hows, R. A., and Zussman, J., 1962a. Rock-Forming Minerals. Vol. 1, Ortho- and Ring Silicates. Longmans, London. Deer, W. A., Howte, R. A., and Zussman, J., 19620. Rock-Forming Minerals. Vol. 3, Sheet Silicates. Longmans, London. FRANKEL, J. J., 1959. Uvarovite Garnet and South African Jade (Hydrogrossular) from the Bushveld Complex, Transvaal. Amer. Mineral., 41, 565. 129 Gass, I. G., and Smewinec, J. D., 1973. Intrusion, Extrusion and Metamorphism at Constructive Margins: Evidence from the Troodos Massif, Cyprus. Nature, 242, 26. Gotpine, H. G., 1969. The Coolac-Goobarragandra Ultramafic Belt, N.S.W. J. Proc. Roy. Soe. N.S.W., 102, 173. Gotp1nG, H. G., 1971. Local and Regional Trends of Serpentinization and Metaserpentinization in the Coolac-Goobarragandra Ultramafic Mass, New South Wales. Geol. Soc. Aust. Spec. Publs., 3, 321. Hasuimoto, M., 1964. The Chemistry and Optics of Prehnite. J. Geol. Soc. Japan, 70, 180. Horpaway, M. J:, 1972. Thermal Stability of Al-Fe Epidote as a Function of fO, and Fe Content. Contr. Minerval and Petrol., 37, 307. Horton, C. O., 1948. Hydrogrossular, a New Mineral of the Garnet-Hydrogarnet Series. Tvans. Roy. Soc. N.Z., 73, 174. Ito, J., and Arem, E. J., 1970. Idocrase : Synthesis, Phase Relations and Crystal Chemistry. Amer. Minerval., 55, 880. Jorprin, G. A., 1968. A Petrography of Australian Metamorphic Rocks. Angus and _ Robertson, Sydney. Liou, J. G., 1971. Synthesis and Stability Relations of Prehnite, Ca,Al,Si,0,,(0H).. Amer. Mineral., 56, 507. Liou, J. G., 1973. Synthesis and Stability Relations of Epidote, Ca,Al,FeSi,0,,(OH). J. Petrology, 14, 381. McLaucuiin, R. J. W., 1967. Thermal Techniques. In J. Zussman (Ed.), Physical Methods in Deter- minative Mineralogy. Academic Press, London. Mires, K. R., 1950. Garnetized Gabbros from the Eulaminna District, Mt. Margaret Goldfield. Bull. geol. Suvv. W. Aust., 103, 108. Moores, E. M., 1973. Geotectonic Significance of Ultramafic Rocks. Earth Sci. Rev., 9, 241. Myer, G. H., 1966. New Data on Zoisite and Epidote. Am. J. Sci., 264, 364. O’Brien, J. P., and RopceErs, K. A., 1973. Xonotlite and Rodingites from Wairere, New Zealand. Minerval. Mag., 39, 233. OtsEn, E. J., 1961. High Temperature Acid Rocks Associated with Serpentinite in Eastern Quebec. Am. J. Sci., 259, 329. Pace, B. M., 1972. Oceanic Crust and Mantle Fragment in Subduction Complex near San Luis Obispo, California. Bull. geol. Soc. Am., 83, 957. Peters, T., 1961. Differential thermoanalyse von Vesuvian. Schweiz. Min. Pety. Mitt., 41, 325. Rosinson, D., 1973. Prehnite from the Contact Metamorphic Aureole of the Whin Sill Intrusion, Northern England. Amer. Mineral., 58, 132. Sexi, Y., 1959. Relation Between Chemical Com- position and Lattice Constants of Epidote. Amer. Mineral., 44, 720. SEKI, Y., and Kurryacawa, S., 1962. Mafic and Leucocratic Rocks Associated with Serpentinite of Kanasaki, Kanto Mountains, Central Japan. Jap. J. Geol. Geogr., 33, 15. Sex, Y., Kurtyacawa, S., and Horikosui, T., 1963. Mafic and Leucocratic Rocks Associated with Serpentinite in the Sasaguri and Omi-Kotaki Areas in the Sangun Metamorphic Belt of Japan. Sci. Rpts. Saitama Univ., B, 4, 193. Spooner, E. T. C., and Fyre, W. S., 1973. Sub-Sea- Floor Metamorphism, Heat and Mass Transfer. Contry. Minerval and Petvol., 42, 287. 130 H. G. GOLDING anp A. S. RAY STEVENS, R. K., Strone, D. F., and Kean, B. F., tabellen. Schweizerbart’sche Verlagsbuchhand ! 1974. Do Some Eastern Appalachian Ultramafic lung, Stuttgart. Rocks Represent Mantle Diapirs Produced Above Watson, K. D., 1942. Zoisite-Prehnite Alteration o a Subduction Zone? Geology, 2, 175. Gabbro. Amer. Mineral., 27, 638. SurpaAM, R. C., 1969. Electron Microprobe Study of Yoper, H. S., 1950. Stability Relations of Grossu Prehnite and Pumpellyite from the Karmutsen arite. J. Geol., 58, 221. Group, Vancouver Island, British Columbia. Zasinsk1, W., 1964. On the Occurrence of a Dispe Amer. Mineral., 54, 256. Vesuvianite Phase in some so-called Hydre TrocerR, W. E., 1956. Optische Bestimmung der grossulars. Bull. Acad. Polon. Sci., Ser. Sci. Gesteinsbildenden Minerale. Teil 1, Bestimmungs- Geogr., 12, 149. School of Applied Geology, University of New South Wales, Kensington, N.S.W., 2033. (Received 27 September 1974) EXPLANATION OF PLATE I A: Gp. 1 rodingite dyke in massive, partly serpentinized harzburgite. Southern slope of Mt. Lightning near Adjungbilly Creek. 2 B: Gp. 1 garnetite showing relict colloform texture. East Ellamatta Creek, Mt. Lightning. Thin section, } ordinary light. Frame length 1-3 mm. Xt C: Porous Gp. 1 garnetite with clusters of euhedral to sub-hedral garnet crystals separated by pores lined } with chlorite. Quilters East, Mt. Lightning. Thin section, ordinary light. Frame length 1-9 mm. \ EXPLANATION OF PLATE II A : Chromite-cored, uvarovitic garnet crystals associated with chlorite (white) and chromite (black) in veinlet penetrating chromitite. Quilters West, Mt. Lightning. Thin section, ordinary light. Frame length 0-6 mm, B: Prebnitite with sutured texture from junction of serpentinized harzburgite and granodiorite. North jj] bank of the Murrumbidgee River near Mt. Lightning. Thin section, polars crossed. Frame length 3-5 7 C : Zoisite euhedra (high relief) separated by prehnite (white) in Gp. 2 rodingite, Haystack Creek, Mt. Lightning. Thin section, polars partly crossed. Frame length 1-6 mm. v; 2 ~~ — hy) — O S Y ) SS o) me ) sq Z, Re =) cy 7 \ AND RAY PLATE I@ G GOLDIN es EEN, OYAL SOCIE JOURNAL R Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 131-146, 1975 Petrology and Petrochemistry of Igneous Rocks in the Mullaley Area of New South Wales JupitH M. BEAN ABsSTRACT—Division of igneous rocks in the Mullaley area into six groups (Bean, 1974), is further supported by petrological, mineralogical and chemical data. The Garrawilla Volcanics comprise a mildly alkaline, low-K, high-Fe lineage, similar to the mildly alkaline Hawaiian lineage, except for higher Fe,O,: FeO+Fe,O, ratios. The latter reflect a build up of volatiles in the more felsic Garrawilla lavas with the result that all rocks more evolved than hawaiites are either vesicular or pyroclastic. The Nombi Extrusives are moderately strongly undersaturated, low-K rocks which differ markedly from Hawaiian basanites in their low-Al values. The Glenrowan Intrusive lineage is a mildly undersaturated, moderately high-K, low-Al, low Fe,O, : FeO lineage. The range in chemistry of the rocks is proposed as the result of fractionation, initially deep within the crust (P<9 kb), and finally im situ within the sills. The Napperby Limburgite, by virtue of its strong degree of undersaturation and high-K content, is a unique rock type in the area. in its high-K, low-Na, high-Al composition. The mildly undersaturated Tambar Trachybasalt is also unique The Bulga Complex is comprised of the more evolved members of a mildly undersaturated, moderately high-to high-k, low Fe,O;: FeO lineage. The phonolites and phonolitic trachytes represent dual differentiation trends—one towards strong Na- and ve-enrichment, the other towards K-enrichment ; similar trends have been observed in the alkaline sequences of Gough Island (Le Maitre, 1962) and Nandewar Volcano (Abbott, 1969). Factors which may have been significant in genesis of the lineages are briefly discussed. Introduction Field relationships, distribution and general petrography of rock types found in the Mullaley area of New South Wales have previously been outlined by Bean (1974). Six groups of igneous rocks are recognized : the Garrawilla Volcanics, the Nombi Extrusives, the Glenrowan Intrusives, the Napperby Limburgite, the Tambar Trachy- basalt and the Bulga Complex. The present paper presents the petrography, mineralogy and chemistry of these rocks and includes discussion on some aspects of petrogenesis. Petrography and Mineralogy Garrawilla Volcanics (Table 1) (a) Alkali olivine basalt and alkali basalt have only positively been identified as non-vesicular flows. Alteration of both phenotrystal and groundmass olivine is extensive and excludes the rocks from bulk chemical study. In the alkali olivine basalts a significant proportion of the olivine occurs as microphenocrysts with core compositions ranging from Fa,, to Fa,,.+ Both the alkali olivine basalts and alkali basalts consist of laths of labradorite, and 1 Olivine compositions, unless otherwise stated, are based on B refractive index measurements (0-002) and the data of Bowen and Schairer (1935). rarely bytownite (An,, to An”), euhedral grains of mauve brown titanaugite and olivine, and grains of a faintly pinkish brown homo- geneous titanomagnetite. Primary interstitial analcime (clear, isotropic, ~=1-488-1-489) is minor in some flows. At least two thick flows contain up to 40 modal percent of a brown glass charged with fine dendrites of opaque oxide. TABLE 1 Modal Analyses of 'Garvawilla Volcanics All modal values are in volume percent Alkali Olivine Rock Type Basalt Hawaiite Specimen No. 716 925 917 | 843 | 837 Olivine .. oF 16 17 6 11 10 Clinopyroxene .. 38 33 16 17 16 Feldspar (predom- inantly plagie: clase) 27 39 27 53 53 Opaques 8 6 7 8 12 Glass Or — — 42 —|; — Altered felsic minerals 11 5 2 11 9 2 Plagioclase compositions quoted as a percentage An are based on 8 refractive index measurements (+0-002) and the data of Chayes (1952). 132 (b) Hawaiite occurs dominantly as non-vesicular flows. The average grainsize of less than 0-1mm_ limits detailed petrography and mineralogy. The rocks are dominated by laths and anhedral grains of plagioclase, ranging in composition from An,, to An,;. These contrast with larger strongly zoned crystals, with a core composition of An,, to Ang3, which are tentatively interpreted as having crystallized at moderately high P/T conditions. Microphenocrysts of olivine range from Fag, to Fag). Groundmass olivine in hawaiite 7231 has an average composition of Fag, (A206 olivine,3,;-20 silicon,,;;,=4:24°; Yoder and Sahama, 1957). Pyroxene occurs as minute euhedral grains of colourless augite or rarely as ophitic plates of mauve brown titanaugite. Cubes of titanomagnetite are optically homogeneous and contain a significant ulvéspinel component (a,=8:427 A in hawaiite 723 and 8-458 A in hawaiite 716). Lamellae of ilmenite are rare in titanomagnetite 757 ; aj—8-428 A. A strongly pleochroic red brown to light straw biotite occurs as anhedral grains adjacent to olivine or, rarely, as euhedral crystals. (c) Mugearite is a minor rock type in the non- vesicular flows. Despite extensive weathering of the vesicular flows and pyroclastic units, which prevents confirmation by analysis, it is proposed that many of these porous rocks are also mugearites. Confirmed mugearites are characterized by abundant small cubes of Fe-Ti oxide, minor very small (less than 2 yw in length) prisms of colourless augite, and abundant feldspar, dominantly oligoclase. Microphenocrysts of olivine elongated parallel to c are minor and biotite is accessory. (d) Soda trachyte has been identified positively only as massive non-scoriaceous lapilli tuffs and volcanic agglomerates. The majority of pyroclastic units and perhaps some of the vesicular flows also appear to be of soda trachyte. Volcanic agglomerate 845 consists of lithic fragments dominated by small laths of alkali feldspar; cubes of opaque mineral and an interstitial felsic phase are minor. Na,O and K,O values of 8-10 and 2-82 weight percent, respectively (partial analysis of specimen 845), are interpreted as approximating the values of these oxides in the alkali feldspar; thus the mineral is lime anorthoclase or anorthoclase. 1 Specimen numbers used in this paper consist of the final three digits of University of New England, Geology Department, Rock Museum numbers. JUDITH M. BEAN (e) Megacrysts occur in at least 84 percent of a the non-vesicular basalts and hawaiites. The } percentage in the mode is commonly less than one, but in the Twin Peaks type lava of the’ small lava domes the percentage is as high as 30, 4)” All crystals are less than 6 mm in diameter and |) ™ most are less than 1 mm. All display marginal resorption and/or reaction with the liquid i which they were enclosed. qe The most abundant megacryst phase is a pa ' mauve brown clinopyroxene (8 =1-694 to 1-698) featuring a marginal zone of spongy pyroxene rimmed by clear titanaugite. Olivine with) core composition ranging from Fa,, to Fag, is” next in abundance. The resorbed crystals of | olivine are consistently richer in forsterite, by 9 to 18 molecular percent, than microphenocrysts § of olivine in the host rock. An iron titanium oxide phase, a dark green spinel (7=1-775) an a grey to green brown spinel (n~1-77) are als ‘| BRweFe BFS SBS San eta = _. = represented. Orthopyroxene (y=1-692), and a mineral altered to an aggregate of clino- | pyroxene, (?) rhodnite, opaque mineral and? feldspar, are very rare. The latter aggregate is | interpreted as the alteration product } kaersutitic amphibole. Inclusion-filled apatites | (cf. Le Maitre, 1962; Wilshire and Standard, 1963 ; Wright, 1968) are common ; in hexagonal cross sec tions the grey brown inclusions a ef aligned parallel to the prism faces, and tabular longitudinal sections (common 1-5 mm in length) they form lines parallel to the c axis. Pyramidal terminations of thi 2 crystals display a narrow zone devoid of inclusions. The very rare occurrence of other § breakdown products of amphibole in the? Garrawilla lavas tends to exclude the origin for inclusion-filled apatites proposed by Edwards (1938) and Benson (1939). ; ‘““ Xenocrystal material of peridotitic origin a as reported by Wilshire and Standard (1963) in the Mullaley basalts, was not found in the Garrawilla rocks. (f) Secondary analcime occurs in vesicles and | pore spaces throughout the Garrawilla volcanie § sequence. Generally the mineral is fehl anisotropic and displays uneven extinction; occasionally it is multiply twinned. The refractive index is low (n=1-483 to 1-484) and | measurements of the cell dimension ay yielded | 13-709, 13-695 and 13-688 A ( A260 analcimegsg— | 20 silicon,,;=1-825°, 1:929° and 1:972;5 respectively ; Cu/Ni radiation). These values | are significantly lower than refractive indices } and cell dimensions of many igneous analcimes and indicate relatively Si-rich composition Similar cell dimensions have been measured om analcime formed by burial metamorphism (Wilkinson and Whetten, 1964; Coombs and Whetten, 1967) and slightly smaller dimensions on analcime formed in a playa lake by diagenetic processes (Ross, 1928; 1941). Analcime with similar properties was attributed by Bradley (1929) to be the product of precipitation at low temperatures following the interaction of Na salts in lake waters with the dissolution products of volcanic ash. In considering the origin of the secondary analcime at Mullaley it is important to note that— (i) no zonation of the mineral could be detected in either a horizontal or vertical direction ; and even if one allows for removal of a thickness of 150 metres of rock from the top of the present maximum erosion level of the Jurassic sedimentary units, the maximum possible depth of burial of the highest development of the analcime must have been less than 300 metres. _ In the light of these factors it is proposed that the analcime was precipitated from ground waters percolating through, or stationary in, the volcanic sequence. It is expected that, during deposition of the Jurassic Purlawaugh and Pilliga Beds, the porous Garawilla sequence would have been saturated with ground water. The deposits of unlithified volcanic ash and lapilli at the base of the sequence could well have provided the Al, Si and Na required for precipitation of the analcime. Nashar and Davies (1960) have demonstrated that solutions, which have derived their constituents by weathering of basalt at atmospheric tem- peratures, can precipitate secondary minerals including zeolites. (ii) Nombi Extrusives (Table 2) (a) Basanite of the Nombi Extrusives consists of small euhedral grains of olivine (Fag), titansalite and opaque oxide, poikilitically enclosed in coarse grained plates of analcime and nepheline ; poikilitic grains of plagioclase (Ans. to Any ) are essential in some specimens. Apatite and strongly pleochroic biotite are accessory. The opaque oxide is an optically homogeneous titanomagnetite with some alteration to titanomaghemite; for titano- magnetite 720 ay,=8:420 A. Analcime is clear, isotropic and n~1-488 ; for analcime 718 A20 analcimeg 3-20 silicon,,, =1-684°. (b) Xenocrysts of peridotitic origin are rare. Olivine (Fa,,) with deformation bands, and orthopyroxene (8=1-672, ~=1-678) surrounded > ms IGNEOUS ROCKS IN THE MULLALEY AREA, N.S.W. 133 by a well-defined reaction rim (consisting of oriented olivine granules and an unidentified interstitial green phase) have been identified. (c) Megacrysts. Crystals of resorbed olivine (Fa,, to Fa,3) and faintly mauve brown clinopyroxene constitute up to 10 volume percent of the basanites. Each pyroxene crystal is surrounded by a spongy aggregate of optically continuous clinopyroxene, opaque mineral and unidentified phases; one weakly birefringent phase stains with methylene blue (Shand, 1939) and may be nepheline. The spongy aggregate is separated from the host basanite by a rim of titansalite optically similar to that of the basanite. TABLE 2 Modal Analyses of Nombi Extrusives All Modal Values are in volume percent Rock Type Basanite Specimen No. 747 | 721 743 749 720 Olivine .. ad 16 18 18 16 11 Clinopyroxene .. 42 42 40 36 45 Opaque .. or 6 6 7 6 9 Plagioclase : 4 5 12 14 7 Nepheline Ne 15; \ ; Analcime ‘ 9 | fre }2s bes pen Altered felsic | mineral sh 8 — _ — — Biotite .. £3 tr | tr Hy | tr 1 Glenrowan Intrusives (Table 3) (a) Alkali dolerite. Crystals of Mg-rich olivine (Fay. to Fag, ; average Fa,,) and glomeroporphy- ritic aggregates of slightly titaniferous clino- pyroxene constitute approximately 15 volume percent of the alkali dolerites. These may be products of crystallization at moderate pressures. The remainder of the rock consists of pheno- crysts of olivine (Fa,, to Fa,,), randomly oriented laths of plagioclase (Ang, to An;.) and prisms of titanaugite (8=1-701). The latter tend to group around the large crystals of Mg-rich olivine. Interstitial areas are filled with plagioclase, rarely alkali feldspar or partly devitrified glass, and minor analcime. A secondary zeolite is probably thomsonite. Approximately 40 percent of the grains of opaque oxide contain one or more lamellae of ilmenite. Extensive alteration of olivine renders the alkali dolerites unsuitable for chemical analysis. (b) Microsyenodolerite (denotes a medium grained intrusive rock equivalent to trachy- andesite as defined by Coombs and Wilkinson, 134 JUDITH 1969). Three textural types of microsyeno- dolerite are recognized (cf. three textural types proposed by Walker, 1923 for teschenites from Scotland) each type representing a different degree of evolution of the Glenrowan magma. TABLE 3 Modal Analyses of Glenvowan Intrusives All Modal Values are in volume percent ; > & ° =) 2 cs) el 3) a| & a ° o 4 a7, Rock Type 5 *, 5 5 3 g 5 E 3 a i|ailolo 21S) 8) orae o | |/2lseiesi13Zis\|Sialgo Ay feb | Salo = o |\"o > on |O|S1Olm& |4/<4/4 jaa Alkali dolerite .. | 889) 16/36) 6} 35) 7) —|—]|] — 725) 17) 27| 6) 47) —| 3|—| — 934] 16) 20) 4) 55}—} 5|—) — 934| 16) 21} 5) 55})—} 3}/—) — Basalt-type microsyenodol- eritey DOG Net ieeka ema Ore | |e 894] 25| 21) 7/380} 2)—| 15) — §84| 21) 17) 4}55) 2;/;—/}—| 1 932) 17) 19} 6) 58) tr | —| —| tr Dolerite-type microsyenodol- nites. - | 930] 16) 22} 5] 53) 2}—|—] 2 891 | 12} 23} 5} 46) 14| —} —| — 909 | 13} 19| 4] 55) 9};—)/—)| — 905 | 11} 16] 5) 56) 12 | —| —) — Gabbro-type microsyenodol- nicely. & 857 | 10") 13) 9) 68) —| —| —| — 848) 5) 18) 557) 97 |) —)| 6) — 893)) 2) 1915 )48). 8}! 18) — * Includes large resorbed crystals. + Includes zeolites. The most basic type, the basalt-type mucro- syenodolerite, differs from alkali dolerite in the absence of phases which may have crystallized at moderate pressures, and in the presence of an evolved felsic phase in interstitial portions of some specimens. Olivine ranges in core composition from Fag, to Fa3,;. Detailed work on the feldspar of specimen 884 indicates a continuous zoning in the laths from a core of labradorite (Or, Ab, , An;, weight percent?), 1 Feldspar compositions quoted as percentages of Or, Ab, An were calculated from values of CaO, Na,O and K,O determined by partial analysis of density fractions. On calculation of the An, Ab and Or contents, the total of feldspar components was greater than 98-12 weight percent in eight of the analyses, and equal to 97-42 in the ninth analysis. To evaluate the range of composition in each density fraction X-ray diffraction traces were run across the (201) peak of each concentrate. M. BEAN through potash andesine (Org Abyy Anyy) and lime anorthoclase, to rims of soda sanidine: (Org, Abso Ang). More differentiated microsyenodolerites are) characterized by an ophitic relationship between’: plagioclase and titanaugite. Olivine in these) dolerite-type macrosyenodolerites ranges in core composition from Fa,, to Fag,,. Interstitial portions of the rock typically contain small prisms and hook-shaped crystals of pyroxene, elongate grains of olivine (composition “_ determined) and cubes and dendritic crystals o opaque mineral, all included in a base of analcime (n=1-488 to 1-489, clear, isotropic) and/or! sanidine. In some specimens the interstitial | phase is comprised solely of analcime and small | laths and tabular crystals of sanidine. The most evolved rocks of the Glenrowan Intrusives are gabbro-type microsyenodolerites, | In these olivine (Fag, to Fag.) is minor and the? more Fa-rich grains are markedly elongate | parallel to c. Titanaugite grains display up to! four oscillatory zones of varying titania content} and a marginal rim of green soda salite, | Feldspar 857 consists of twinned micropheno-/ crysts, rarely of bytownite—An,, and commonly | labradorite (average Or, Ab,, An;) weight? percent), zoned to potash andesine, and joined / abruptly by a ragged margin of untwinned } sanidine. Groundmass feldspar includes small | laths of plagioclase, equant crystals of anor © thoclase and anhedral grains of soda sanidine (Oryg Aby; Ang). As in all the microsyenodolerites the opaque © mineral is dominantly titanomagnetite with fine lamellae of ilmenite. In addition numerous © small cubes and tabular crystals of ilmenite” build skeletal grains and pyrite occurs as cubes. either included in the titanomagnetite or as/ isolated grains. |= i — 8 = ee BS Sa 85 Ss SE «tw a brown amphibole (grouped in_ parallel <= ae — ee See ee = are evident. . Labradorites of the Glenrowan Intrusives are | high temperature, structurally disordered types. Values of 26(43;)—29q31) (Smith and Yoder, 1956) and T'26(.9)+28;131) —4931) (Smith and | ss (An;,) are 1-99 and 1-96, and 0-92 and 0-86, | respectively. _ £- &- 38 Lee ass IGNEOUS ROCKS IN THE MULLALEY AREA, N.S.W. a Napperby Limburgite (Table 4) )| (a) Limburgite. Apart from the nodules and olivine xenocrysts, the limburgite consists of “) small euhedral grains of olivine (Fa,,) and i) | titansalite, cubes of Fe-Ti oxide (aj=8-376 A), '8}| small laths of alkali feldspar and glass. tt TABLE 4 = Modal Analyses of the Napperby Limburgite (943 and i 944) and Tambar Trachybasalt (936) u All Modal Values are in volume percent ls y Rock 943 | 944 | 936 | a {i | Olivine aa a aa 26 23 13 Clinopyroxene ae at 38 35 23 “) | Glass hy bs is 31 35 — Alkali feldspar Ly i 0 3 — jy2 | Opaque mineral... ois 5 4 4 Feldspar zeolites .. ye _— — 60 (6) Dunite nodules. Olivine of the nodules ranges in composition from Fa, to Fa,, ; deform- ation bands subparallel to (100) and undulose extinction are evident. A260 olivine,,,—20 silicon,,, equals 4:5° (Cu/Ni radiation), indic- ating an average composition of Fa,,9. Olivine xenocrysts, broken from the nodules, constitute approximately 20 volume percent of the limburgite. Tambar Trachybasalt (Table 4) The trachybasalt is characterized by a high percentage of feldspar, including alkali feldspar. Partly resorbed crystals of olivine (Fa,,, Fa,,) are minor. Laths of labradorite, euhedral grains of titanaugite and ophitic and skeletal Higrains of Fe-Ti oxide are the essential constituents. Bulga Complex (Table 5) (a) Trachyandesite 946 contains minor resorbed and partly replaced intratelluric crystals of olivine (Fa,;, Fag,), titaniferous augite, lab- radorite (An,, to An;,) and opaque mineral. _ The remainder of the rock consists of titaniferous augite, laths of feldspar (labradorite An;;_;3 and potash andesine/potash oligoclase— set {@=1:551, 1-548), cubes of titanomagnetite (aj= * 1/8-462 A) with lamellae of ilmenite, minor olivine Fa,, and accessory apatite. (6) Tristanite 941 contains minor intratelluric crystals of olivine (Fas, to Fa,,) and inclusion- filled. apatite. Apart from these, the -rock consists of phenocrystal (Fa,,) and groundmass {jolivine, skeletal grains of acmitic titaniferous laugite or salite and cubes of titanomagnetite 135 (a)=8-466 A) with some lamellae of ilmenite. Alkali feldspar, consisting of equidimensional cores of lime anorthoclase (Or,; Absgy Atgg weight percent, B=1-540 to 1-536) surrounded by a sharply delineated rim of homogeneous sanidine (Ory, Abs, Ang; ®=1-532), is the predominant mineral. Isotropic analcime occurs interstitially ; n=1-492, A260 analcimegs, —20 silicong,,=1-652°. Secondary zeolite, dominantly natrolite, is minor. (c) Phonolitic trachyte. and microsyenite. Microsyenite, in Old Bando Ridge and Mount Mullaley, is medium grained and hypidiomorphic granular. It consists of alkali feldspar (showing incipient exsolution and some complex twinning), colourless salite or light green soda salite (specimen 990—ZAc=44 to 45°; §=1-710), opaque mineral, and very minor olivine. Peg- matoidal phases consist of alkali feldspar, aegirine augite, nepheline and isotropic analcime. Adjacent to these phases, magnetite is altered along {111} planes. TABLE 5 Modal Analyses of Rocks from the Bulga Complex All Modal Values are in volume percent Rock Type | Trachy-| Trist-| Phonolitic | Phono- andesite | anite Trachyte lite Specimen No. 946 941 | 990/999] 104) 065 Olivine .. 6 l1l1;—} 4] 3 — Clinopyroxene| 20 8} 6] 11] 13 12 Opaque mineral .. 9 5 3 5 3 7 Feldspar_ .. 65 76 | 91 | 80 | 81 Analcime .. _ —|—|— 81* Nepheline .. —_ —|— |} — + — * Nepheline> 20%. By contrast, in phonolitic trachytes the alkali feldspar is optically homogeneous and domin- antly sanidine (P=1-:531, 1-530). Micro- phenocrysts, probably of lime anorthoclase (8=1-542 to 1-535), are prominent in porphyritic types such as Coogal Mountain. The rocks can be subdivided on the basis of the pyroxene. Phonolitic trachyte 999 (Mount Talbareeya) consists of soda sanidine (Or,, Ab;; An, and Or,, Ab;, An, weight percent), soda. salite (X-pale grass green, Y-pale grass green, Z-pale brown green; ZAc=45 to 47°;. B=1-715) rarely with cores of titaniferous salite, fayalitic olivine (microphenocrysts Fag, and Fag,) and an optically homogeneous’ magnetite or. titano- magnetite (a,=8-414 A). © 136 Phonolitic trachyte 104 (The Billies) is a soda sanidine-soda ferrosalite (X-green, brown green, Y-intense green, Z-brown, Y>X>Z; ZaAc=51 to 54° ; a=1-719, y=1-745 ; 2Vy=62 to 63°)— fayalitic olivine rock. The olivine is distinctly yellow, DR#0-05, well developed cleavage parallel to (010); value of A20 olivine,,,—20 silicon,,,; is beyond the value given by Yoder and Sahama (1957) for Fa, 9. Phonolitic trachytes constituting Mundry Hills and Mount Baloola are exceptionally fine grained and consist of sanidine, soda hedenber- gite (ZAc=56 to 62° ; 8=1-750), yellow Fa-rich olivine, minor nepheline and opaque oxide. (dz) Phonolite. The phonolites consist essentially of slender laths of sanidine (8=1-528) and minor lime anorthoclase (8=1-534, 1-532), and smaller tabular grains of nepheline euhedral towards aegirine augite (X—brown, Y-green brown, Z-intense green, Z>Y=X; B=1:-770, y=1-789 Ratz Castle 065 and Mount Nombi ; y-x< 0-04 ; Zc increasing from 53° to at least 74° as the acmite component increases*). Aegirine (faint brown to near colourless ; ZAc=79° to 90°, commonly 88° to 90° ; y-«> 0-045) occurs as very small tabular crystals adjacent to interstitial analcime. Magnetite is partially altered along {111} planes to hematite. Preferential replacement of either the alkali feldspar or the nepheline by natrolite is wide- spread. Analcime syenite, consisting of alkali feldspar, analcime and minor soda pyroxene, occurs as schlieren in the phonolite of Carthian Hill. Analcime syenite also constitutes the core of the Mount Bulga plug dome. The latter rock (069) is hypidiomorphic granular and comprised essentially of alkali feldspar, analcime (isotropic ; n=1-488 to 1-490; A20 analcime,,,—26 silicong31~1-680°) and soda salite (X-light green, very dark green, Y—light brownish green, brownish green, Z—brown, light brown, dark brown, 4==¥ > X > B=1i1s) Ai" ZAc—aZ to 53°). The latter mineral varies in colour intensity irregularly within and between grains. Marginal zones with 8 =1-729 and small discrete grains occurring adjacent to analcime are aegirine augite. Nepheline and apatite are minor and natrolite of late magmatic origin is prominent as the replacement product of the felsic minerals. 1 From study of the optical properties of a number of analysed specimens of aegirine augite it is concluded that ZAc and y-« can be valid indicators of the percentage acmite component in a soda pyrexene ; the Bulga aegirine augites are generally too fine grained for measurement of 2V and sign. JUDITH M. BEAN | i | Phonolite 078 from Mount Bulga, which is ; regarded as the final liquid in the differentiation i process, consists of irregular laths of alkali i feldspar and euhedral grains of nepheline (~35 | volume percent). A green pyroxene occurs in © the lens-shaped zones in the rock. Magnetite — virtually lacks any alteration to hematite. (e) Intratelluric crystals in the phonolitic trachytes and phonolites. Intratelluric crystals of alkali feldspar, olivine, amphibole, inclusion-— filled apatite and opaque oxide are rare in the phonolitic trachytes. By contrast, crystals a alkali feldspar (8=1-533 to 1-528 ; extensive altered to kaolinite and/or zeolites and showing incipient exsolution) constitute up to 35 volume percent of some specimens of phonolite (e.g. The Pinnacle phonolite) ; minor quantities o ) kaersutite, opaque oxide and _ inclusion-filled | apatite occur in the majority of specimens. i Single crystals of kaersutite measure up toll 4 mm in length, are strongly pleochroic (X—light | yellow to pink brown, Y—intense reddish brown, © Z-greenish brown, Y>Z>X), «=1-683, oe 12699; 2. =15-+5°, Zac=0° and y—«<0-04, § Compositional zoning is indicated by marke changes in colour. The majority of the crystals are completely pseudomorphed by an aggregate | of aegirine augite and magnetite altering to hematite. By contrast, aggregates of similar | origin in the phonolitic trachytes consist of soda salite or soda ferrosalite and magnetite. é ¥ Chemistry Chemical analyses and norms of igneous rocks from the Mullaley area are listed in Tables 6 to 8. As noted previously some rock types are too altered for meaningful analysis. In dis- tinguishing the different groups of rocks, the significant parameters are found to be K,O, Fe,O, : FeO0+Fe,O, and Al,Os. In distinguishing lineages the present author regards it as important that K,O and Na,O levels be considered separately ; ; on the commonly used plot of K,O versus Na,O the distinctive feature of a particular lineage is often masked by the level of the other oxide. It is | surely genetically significant that in the ten | alkaline lineages plotted on Figures 1 and 2, the | | range of K,O in the basic rocks is greater than | the range of Na,O in the same rocks. This | difference in the behaviour of K,O and Na,O | during genesis of a_ parental basic magma is | evident in the Mullaley rocks where all groups, except the Tambar Trachybasalt, are average-— Na types (definitions of terms low-, average-, moderately high- and high- are given in captions © of Figures 1 and 2). The K,O values of the rock | i | | i ) i ) i | | | b IGNEOUS ROCKS IN THE MULLALEY AREA, N.S.W. 137 — i= o 2 ® a -_ As Ney ® = 10 ro) N ie} 2 8 6 € 4 ® oO [ o a if he is ® = 2 fo) N ie] 2 10 30 50 70 90 Differentiation Index Ficure 1A.—Generalized trend lines for Na,O values versus differentiation index in ten alkaline and mildly alkaline lineages. Wa—theralites from Lake Waihola, East Otago (Coombs and Wilkinson, 1969) ; ST—Square Top intrusion, Nundle, N.S.W. (Wilkinson, 1965) ; Om—nepheline basanites and associated pegmatoids from Omimi, East Otago (Coombs and Wilkinson, 1969) ; Heb—Hebridean alkaline province (Tilley and Muir, 1962, Table 2, Nos. 1 and 2; Muir and Tilley, 1961, Table 4, Nos. 1, 2 and 10) ; TC—lavas from Tristan da Cunha (Baker et al., 1964) ; Ha—Hawaiian mildly alkaline province (averages ; Macdonald and Katsura, 1964, Table 10); Ho—alkali basalt—hawaiite—mugearite—trachyte lineage from the Hocheifel province (Huckenholz, 1965a); N—Nandewar Volcano (Abbott, 1969) ; BJ—Black Jack sill near Gunnedah (Wilkinson, 1958) ; Go—lavas from Gough Island (Le Maitre, 1962). Line AB constructed through points Na,O=9%, D.I.=100 and Na,O=2%, D1I.=10. Line CD constructed through points Na,O=5-35%, D.I.=70 and Na,O=2-25%, D.I.=20. Lineages with Na values falling in area A-B-C-D are regarded as average-Na lineages, those plotting below CD as low-Na lineages, and those above AB as high-Na lineages. Ficure 1B.—Plot of Na,O values versus differentiation index for analysed specimens from the Mullaley area. (Solid circles—Garrawilla Volcanics ; open circles—Nombi Extrusives; solid squares—Glenrowan Intrusives ; ieross—Nappetby Limburgite; open triangle—Tambar Trachybasalt ; solid triangles—Bulga Complex. Lines ~ AB and CD and Go as in Figure 1A. 138 JUDITH M. BEAN Weight percent 10 30 50 70 90 Differentiation Index K50 Weight percent FicurE 2A.—Generalized trend lines for K,O values versus differentiation index in ten alkaline and mildly) alkaline lineages. Cross—Hawaiian basanite (average; Macdonald and Katsura, 1964, Table 10). Other’ symbols as in Figure 1A. Line EF constructed to separate lineages regarded as low-K lineages (below) from) those regarded as moderately high- and high-K lineages (above EF). FicurE 2B.—Plot of K,O values versus differentiation index for analysed specimens from the Mullaley area. | Symbols as in Figure 1B. Line EF as in Figure 2A. groups range from low in the Garrawilla composition from labradorite in the basalts to) Volcanics and Nombi Extrusives, to moderately anorthoclase in the trachytes; sanidine is, high in the Glenrowan Intrusives and possibly absent. By contrast, lineages which plot above | the Bulga complex, to high in the Napperby line EF feature intermediate rocks which are: Limburgite and. Tambar Trachybasalt. two feldspar types—plagioclase in association The distinction between low-K and with sanidine, and more evolved rocks in which moderately high-K lineages at the line EF in Sanidine is the sole feldspar. i) Figure 2 correlates with the feldspar mineralogy In evaluating Fe in the Mullaley lineages a of the rocks. Lineages classified as low-K plot in an AFM diagram is not distinctive ; all lineages correspond to those of Coombs and _ three lineages are high-Fe types. By contrast, Wilkinson (1969) in which Na,O: K,O ratios Fe,0,;: FeO+Fe,O, plotted against OD.L/) exceed 2:1; the rocks are one feldspar types, (Figure 3) is significant ; the high Fe,;0, : FeO+_ there is generally a continuous range in Fe,O, ratios of the Garrawilla lineage distinguish 2. eee a, eee eo eee IGNEOUS ROCKS IN THE MULLALEY AREA, N.S.W. Fe,03+ FeO Weight percent — Fes03 ° 30 50 70 90 Differentiation Index FicurE 3.—Plot of Fe,0,:FeO+Fe,0, against differentiation index for analysed specimens from Mullaley. Symbols as in Figure 1B. Hawaiite 809 and Trachyandesite 946 are anomalous. Generalized trend lines for Hocheifel (Ho), Hawaiian mildly alkaline (Ha), Square Top (ST) and Hebridean alkaline (Heb) lineages included for comparison. these rocks from those of the Glenrowan Intrusives and Bulga Complex which possess low ratios. A third parameter found to be critical in assessing the Mullaley rocks is Al,O, plotted against D.I. As seen in Figure 4 the Garrawilla Volcanics can be regarded as average-Al rocks, the Tambar Trachybasalt as a high-Al rock and the Nombi Extrusives, Napperby Limburgite and Glenrowan Intrusives as low-Al rocks. Garrawilla V olcanics From the limited range of rock types suitable for chemical analysis (Table 6), it is proposed | that the Garrawilla Volcanics constitute a mildly alkaline (Coombs, 1963), low-K, average-Na, | average-Al, high-Fe lineage. This lineage differs from the mildly alkaline lineage at Hawaii (Macdonald and Katsura, }1964) only in its Fe,O,: FeO+Fe,O, ratios (Figure 3). The high and rapidly increasing Fe,0, : FeO+Fe,0, ratio of the lavas is regarded 139 as a primary magmatic feature reflecting a build up of volatiles in the lavas with increasing evolution. The high percentage of modal magnetite in the hawaiites and mugearites, and the tendency of the lavas, particularly the felsic types, to be vesicular or to erupt explosively, support the proposal that the high Fe,O, was a magmatic feature and not the result of post crystallization oxidation. Also pyroxene is minor and biotite constitutes up to 1-5 volume percent of the hawaiites and mugearites. In the absence of chemical analyses of the soda trachytes, it is proposed that these rocks may be Si-saturated types containing hy. In accord with Osborn (1959, 1960), it is probable that the extensive precipitation of titanomag- netite in the hawaiites and mugearites would have allowed a build-up of Si in the more evolved lavas. If so, the delicate balance of the Garrawilla lineage astride the thermal ridge (located experimentally at low pressures along Al 2 03 Weight percent 30 50 70 90 Differentiation Index FIGURE 4.—Generalized trend lines for Al,O, values against differentiation index for six alkaline and mildly alkaline lineages. Ho bas—basanites from the Hocheifel province (Huckenholz, 1965b); Ha bas— Hawaiian basanite (average ; Macdonald and Katsura, 1964, Table 10). Other symbols as in Figure 1A. Analysed specimens from Mullaley plotted as individual points. Note low-Al values of the Napperby Limbur- gite (cross), Nombi Extrusives (open circles) and Glenrowan Intrusives (solid squares), and the high-Al value of the Tambar Trachybasalt (open triangle). 140 TABLE 6 Analyses of Rocks from the Garrawilla Volcanics and Nombi Extrusives, Mullaley Area, N.S.W. JUDITH M. BEAN 1 2 3 4 5 6 v | 8 9 10 11 lla 12 SiO, 45-91) 46-58) 47-89) 47-84) 48-23) 47-33] 48-03) 48-90 41-75} 41-01) 41-01) 43-43 @ TiO, 2°40) 2-15) 2-05) 3-03) 2-40) 2-95) 3-10) 2-33 2-45] 2-30} 2-30) 2-50 10 Al,O, 14-80| 14-80] 14-53) 16-60) 16-40) 16-60} 16-50| 17-38 11-62] 11-46) 11-46] 11-42 4 Fe,0; 2-78} 3°31] 3:23) 4-52) 3:97) 2-86] 4:73) 6-48 3°20} 5:72) 3:00) 4-17 . FeO 10-37) 8-32] 8-03) 8-17); 7:27) 8-86] 8-03] 6-41 9-50) 8-27) 10:72) 8-35 We MnO Sle ‘14 -14 *15 -13 -13 “HS “14 +14 “14 +14 Wy mm MgO 8-39] 7-83) 7-60) 4-90! 6-00} 4:50) 4-90; 3-51 11-60} 11-70} 11-70] 10-53 CaO 8-60} 8-80) 8-70) 7-75) 7-95) 8-60) 7-00] 5-65 11-56} 10-68) 10-68) 10-75 4 Na,O 3:14) 3°50} 3-87] 3-66) 3-90) 4-05| 3-97) 5-33|8-10| 2-85) 2-70) 2-70) 3-30 ii K,O 1-39 -98 -73| 1-55} 1:40) 1-55) 1-80) 1-52) 2-82 70 -80) -80 -70 iD P,0; 65 “79 ‘75 +50 -70) 1-26 +52 *82 82 *56) +56 66 } H,O+t 1-59) 2° 06) 1-76) 4) 2-27) Laon -50| 1-18 2-93} 3°72! 3°72) 2-66 4 H,O- 12 -61 rip 19 +41 -21 -40 +22 -56 *94) +94 «99 a Total 100-31/ 99-87 | 99-85 |100-27/100-03) 99-91 | 99-63 | 99-87 99-68 |100-00/ 99-73 | 99-63 i Norms Norms g Or 8-21) 5-79| 4:31) 9-16] 8-27] 9-16] 10-64] 8-98 4-14| 4-73) 4:73] 4:14 i" Ab 22-74) 28-97] 32-74] 30-97] 33-00) 31-61] 33-59] 43-83 8-14] 10-09) 6-74} 15-80 ) An 22-19) 21-78) 20-13] 24-30] 23-12 | 22-55) 21-90] 19-02 16:85] 16-79) 16-79} 14-29 bh Ne 2:07 °35) — _— — 1:44); — -69 8-66] 6:91) 8:73} 6-57 \ Di 13-23) 13-51] 14-66} 8-83} 9-47} 9-77) 7:64) 2-93 28-25] 25-89] 26-29] 27-78 i Hy — — 1-13; 5-30) 1-71) — L:3ii —— = aa = = ki Ol 20-06) 16-08] 14-23] 6-65} 10-84) 11-49} 9-15] 7-31 18:97] 16-97] 21-78) 15-08 a Mt 4-03) 4-80} 4-68] 6-55) 5-75) 4:15) 6-86] 9:39 4-64) 8-29) 4:35) 6-04 it Ap I-52) 1:84) 1-75) 1-L7) 1-63) 2-94) 1-21) 1-91 1<-91))" 1-3, ESL isos Ul 4-56] 4-08] 3-89) 5-75) 4-56) 5-60] 5-89] 4-43 4°65] 4:37, 4°37] 4-75 i Total 100-32) 99-87 | 99-85 |100- 28/100: 03) 99-93 | 99-65 | 99-89 99-70|100-01| 99-75 | 99-64 g Du 33-5 | 36-1 | 38-0 | 40-7 | 42-0 | 42-8 | 44-8 | 54-3 21-8 | 22-8 | 21 27-6 m Normative Wn An x 100 = 49-4 | 42-9 | 38-1 | 44-0 | 41-2 | 41-6 | 39-5 | 30-3 67:4 | 62:5 | 71-4 | 47-5 fay Ab+An m™ i 1. Garrawilla hawaiite transitional to basalt (924) LG 2. Garrawilla hawaiite transitional to basalt (724) 1 g 3. Garrawilla hawaiite transitional to basalt (723) 10 4. Garrawilla hawaiite (716) ic 5. Garrawilla hawaiite (758) iC 6. Garrawilla hawaiite (809) vt 7. Garrawilla hawaiite (717) 1X 8. Garrawilla hawaiite transitional to mugearite (757) it 9. Non-scoriaceous buff coloured lapilli tuft/volcamic agglomerate (845)—soda trachytic composition. 10. Nombi basanite (721) 1l. Nombi basanite (748). Analyst G.I.Z. Kalocsai. (Om lla. Nombi basanite (748) recalculated with Fe,O, equal to 3 weight percent. Rin 12. Nombi nepheline hawaiite (720). * 12a. Nombi nepheline hawaiite (720) recalculated with Fe,O, equal to 3 weight percent. Analyses 1-10 and 12 by J. M. Bean. me @ tay the plane of critical undersaturation in the their low-Aland low total alkalis. It is proposed | ti basalt tetrahedra) would have been lost and that this unusual chemistry could be the result jj % Si-saturated liquids evolved. of accumulation in a basanitic magma bey h crystals of olivine and clinopyroxene, fraction-\j Nombi Extrusives ated from a larger body of basanitic magma at} ah The Nombi basanites are moderately strongly pressures of «9 kb. In fact, if 10 weigi at Hl undersaturated, low-K, low-Al, low total alkalis _ percent of olivine and clinopyroxene, in a ratio | % rocks (Table 6). They differ significantly from of either 1:1 or 1:2 (compositions used @ lg the basanites of Hawaii (Macdonald and Katsura, those of olivine and clinopyroxene whic i 1964) and Hocheifel (Huckenholz, 19566) in precipitated from an alkali olivine basalt re toy IGNEOUS ROCKS IN THE MULLALEY AREA, N.S.W. TABLE 7 Analyses of Glenvowan Intrusives, the Napperby Limburgite and the Tambar Trachybasalt from the Mullaley Avea, N.S.W. 3 Normative An x 100 Ab+An . Glenrowan alkali dolerite (725) . Glenrowan basalt-type microsyenodolerite (932) . Glenrowan basalt-type microsyenodolerite (884) Glenrowan dolerite-type microsyenodolerite (930) . Glenrowan gabbro-type microsyenodolerite (857) . Glenrowan gabbro-type microsyenodolerite (848) . Napperby Limburgite (944) Tambar Trachybasalt (936) DAB Pwre composition at 9 kb and 1,220°C; Green and | Ringwood, 1967), is subtracted from the Nombi basanite average composition the resulting | composition is very close to that of the average ' Hawaiian basanite. To test the feasibility of this proposal detailed microprobe work on the Megacrysts of olivine and clinopyroxene in the basanites is required. Both the complete isolation of some outcrops of basanitic rock from all outcrops of Garawilla Volcanics, and the greater than five percent ne, suggest that it is unlikely that the basanitic Magma was derived from the Garrawilla magma by any direct fractionation process (Green and Ringwood, 1967). — RO anwmoatbvo-+! bo Analyses 1-8 by J. M. Bean. Glenrowan Intrusives The alkali dolerites and microsyenodolerites of the Glenrowan Intrusives constitute a mildly undersaturated, moderately high- to high-K, low-Al, low total alkalis, low-Fe,O, : FeO lineage (Table 7). The low Fe,O,: FeO+Fe,O, ratios indicate a low oxygen fugacity in the magmas. A low percentage of titanomagnetite (relative to that in Garrawilla lavas of similar D.I.) and continued crystallization of olivine into evolved rock types are in accord with such conditions. Evolved phases of the microsyenodolerites, containing analcime, aegirine augite and no olivine, indicate a higher oxygen fugacity in the final stage of fractionation. 142 TABLE 8 Analyses of Rocks from the Bulga Complex, Mullaley Avea, N.S.W. JUDITH M. BEAN 1 2 3 4 5 6 7 8 9 10 SiO, 49-35 | 52-15 | 57-62 57-89 59-28 | 57-53 | 56-40 | 57-90 ¥ TiO, 1-20 +74 -48 | abs abs abs abs abs | Al,O3 17-65 18-52 | 18-39 18-67 19-19 | 19-58 | 19-48 | 20-60 Fe,0O, 2-76 2-20 | 2+32 2-68 3:32 | 2:69 | 2:26) 2:05 | FeO 8-60 7-81 4-61 4-21 191 1:94 |} 2-12 Vey, MnO -13 *15 +15 +15 -13 +09 oa Hf -16 ’ ; MgO 3-43 1-76 -18 -02 ‘07 “12 *25 02 2 | CaO 6-58 4-07 | 2-30 2-36 1-52 1-25 1-30 1-15 i Na,O 4-17 5:85 6-55 6-27 | 6-45 7:70 8-10 8-87 | 10-40 | 9-17 — K,0 2-66 3-52 5-30 5-83 | 5-50 5:33 5:68 | 4-95 5°18 | 5-22 P50; 1-03 1-05 “19 -09 abs abs abs abs H,O+T 2°12 1-89 1-39 1-74 1:58 | 2-46 3:41 *95 H,O- +33 -29 41 “17 30 22 *33 +16 Total 100-01 | 100-00 | 99-89 | 100-08 100-33 | 99-66 | 99-54 | 99-74 Norms Or 15-72 | 20-80 | 31-32 34-45 31-50 | 33-57 | 29-25 | 30-61 Ab 32-99 | 38-46 | 42-06 39-01 46:50 | 38-87 | 36-57 | 31-56 An 21-59 13-33 5-14 5-59 2:07 30 = = Ne 1-24 5-98 7:24 7-61 10-10 | 16-07 | 19-55 | 24-69 q Cor — -20 — — — — — — € Ac — — — — — — 2-11 5-93 "I Na met — — —_ — — — — *96 Di 3-61 — 4-44 4-92 2-27 3-48 | 5:59 | 4-71 - Wo — — -- — 1-20 719 —_— oA, Hy — | — | - | —-— }-—}—] = | Ol 13-73 12-02 3:18 2-49 — — 51 —_— Mt 4-00 3-19 3:36 3-88 4-81 3:90 | 2:22 — Ap 2-40 2-45 +44 21 == = = = ll 2-28 1-41 ‘91 ae — ae — — ; a ee ’ Total 100-01 | 100-02 | 99-89 | 100-07 100-33 | 99-66 | 99-54 | 99-74 A DT. 51-2 66-7 82-2 82-6 89-5 | 9l-3 89-1 88-1 > ‘ee — Normative - An x 100 } ar . D5. . . . . . . peas 39-6 25°7 10-9 12-5 4-3 0:8 0-0 0-0 a . Trachyandesite (946), small dome east of Wyuna homestead. Analyses 1-10 by J. M. Bean. t . Tristanite (941), Bullomins Knob on Bando Station. . Phonolitic trachyte (999), Mount Talbareeya. . Phonolitic trachyte (104), The Billies. . Phonolitic trachyte (031), small quarry east of Kyndalyn homestead. . Phonolite (074), Mount Bulga. . Analcime syenite (069), Mount Bulga. . Fine grained phonolite (078), Mount Bulga. 10. Fine grained phonolite (079), Mount Bulga. 1 2 3 4 5 6. Phonolite (065), Ratz Castle. 7 8 9 0 The composition of the Glenrowan magmas, prior to their 7m situ differentiation in sills at shallow depths, may be the result of fractionation of the magmas deep within the crust (P<9 kb). . The low-Al, low total alkalis and low normative plagioclase values of the rocks correlate with the high percentage of large crystals of Mg-rich olivine and slightly titaniferous clinopyroxene seen in the alkali dolerites. In the more differentiated Glenrowan rocks similar crystals are not visible, but the chemical character of the rocks suggests that such crystals may have been present ; with the longer time required for fractionation the crystals could have been completely assimilated by the magma. Napperby Limburgite The Napperby Limburgite, with its high | content of dunite nodules, strong degree of © undersaturation and high-K value (Table 7) is unique in the Mullaley area. a z %. SsaTtees Sse se KS .£.3 a IGNEOUS ROCKS IN THE MULLALEY AREA, N.S.W. Calculations (Table 9, No. 2) using the composition of olivine from a dunite (atomic ratio Mg: Fe?+=91-1:8-9; Deer, Howie and Zuassman, 1962) and an alkali olivine basalt composition (Green and Ringwood, 1967), indicate that O’Hara’s (1968) proposal (that lherzolite fractionation can produce crystal/ liquid mixtures with strongly undersaturated compositions) is not an acceptable mechanism for genesis of the Napperby Limburgite. By contrast, the limburgitic composition may have been derived by the inclusion, in a basanitic magma derived at depth by partial melting, of 720 weight percent residual mantle material (Table 9, No. 3). However, the high-K value excludes a direct genetic link between the Nombi basanitic magma and a basanite able to produce the Napperby Limburgite. Tambar Trachybasalt As indicated in Table 7 the Tambar Trachy- basalt is a mildly undersaturated!, high-K, low-Na, Al-rich rock. It is almost identical in major element chemistry to the high alumina liquid obtained by Green and Ringwood (1967, Table 15) by fractionation in an alkaline basaltic liquid at 9 kb and 1,220°. In the Tambar rock, the presence of very minor resorbed crystals of olivine and a low TiO, content (removal of titaniferous clinopyroxene) suggest the operation of a similar fractionation process in derivation of the Al-rich magma. The initial alkaline olivine basalt magma would need to have possessed a high-K value. Bulga Complex From the limited range of rock types found in outcrop it is proposed that rocks of the Bulga Complex constitute a mildly undersaturated moderately high-K, average-Na, high-Fe lineage (Table 8), similar to lineage F as proposed by Coombs and Wilkinson (1969). Both the dominance of evolved rock types and the restricted areal extent of outcrop of the Complex, suggest that a “cupola” or “ high”’ in a large magma chamber existed beneath the area of outcrop. Fractionated liquids from throughout the large chamber could have migrated to such a “high” prior to their extrusion. 1 The small percentage of hy in this rock is very probably the result of post-magmatic oxidation. The modal percentage of opaque mineral is low (3-9) and thus it is unlikely that the high percentage of Fe,O, . in the chemical analysis, represents magmatic e' 3 ei 143 The phonolitic trachytes and _ phonolites represent dual fractionation trends. The phonolites crystallized from liquids fractionating towards strong Na-enrichment, and increasing degree of undersaturation; by contrast, the phonolitic trachytes crystallized from liquids fractionating towards K-enrichment at a fairly constant degree of undersaturation. The former trend occurred under hydrous, peralkaline conditions and oxygen fugacities either higher than, or at least decreasing at a slower rate than, TABLE 9 Calculated Compositions Relevant to Genesis of the Napperby Limburgite 1 2 3 SiO, 43-3 44-6 42-9 TiO, 2°5 2-0 2-1 Al,O, 10-0 11-8 10-1 Fe,O, 3:6 1-5 2-7 FeO 8-9 11-6 10:2 MnO -2 +2 +2 MgO 16:8 18-2 18-5 CaO 9-9 7:3 9-7 Na,O 2-7 2-1 2-4 K,O 1:4 6 “7 P.O; -7 -2 6 Or 8:3 3:5 3-9 Ab 5:2 15-7 5:8 An 11-0 21-0 14-7 Ne 9-5 1-1 8-0 Di 26-7 11-2 23:7 Ol 27-7 41-1 34:7 Mt 5:2 2-2 3-9 Ton 4-8 3:8 4-0 Ap 1-6 “5 1-3 D.I. 23 20 18 1. Napperby Limburgite calculated anhydrous. 2. Alkali olivine basalt composition as used by Green and Ringwood (1967) in experimental runs, plus 25 weight percent of olivine. Olivine composition No. 6, Table 2. Deer et al. (1962). 3. Average Nombi basanite plus 20 weight percent olivine. Composition of olivine as for 2. those under which the phonolitic trachyte trend occurred (supported by occurrence, composition and modal percentage of olivine, pyroxene, magnetite and analcime). The phonolitic trachytes crystallized in anhydrous conditions with oxygen fugacities, either lower than or decreasing at a more rapid rate than in the phonolitic trend (cf. Nash and Wilkinson, 1970). It may be significant that the phonolites occur in endogenous lava domes within which the volatiles were contained during crystallization ; by contrast, the phonolitic trachytes occur as flows and exogenous domes. 144 A plot of the phonolites in Petrogeny’s Residua System at Py,0=1,000 bars (Fudali, 1963) indicates that the rocks plot in the thermal deep in the undersaturated portion of the system (Figure 5). The most evolved phonolite 078 plots close to the minimum melting composition at 750+7°C. As there is no thermal deep in a similar portion of this system under anhydrous conditions (Schairer, 1957) the trend in the phonolitic trachytic liquids towards the Or-Ks side of the system (K-enrichment trend) is as expected. SILICA ALKALI FELDSPAR SS 065 a@a 4104 0744999 0594 o78 Ne Ks Weight percent FicurE 5.—Plot of normative salic constituents (less anorthite) of the Bulga Complex phonolitic trachytes (open triangles), the Bulga Complex phonolites (solid triangles) and the Gough Island aegirine augite trachytes (solid circles) (Le Maitre, 1962) in the system Ne-Ks-Qz (weight percent). The boundary curves, M— minimum on the liquidus surface along the nepheline- alkali feldspar boundary curve, are taken from Fudali (1963, Figure 1). Liquidus_ relationships were determined in part of the Ne-Ks-Qz-H,O system at PH,0 of 1,000 bars and the data projected onto the anhydrous base of the tetrahedron, A similar divergence of fractionation trends in the late stage of fractionation of an alkaline magma is evident in the Gough Island (Le Maitre, 1962) and Nandewar (Abbott, 1969) sequences (Figures 5 and 6). In all three lineages a strong Na-enrichment trend only occurs under hydrous conditions. Conclusions Division of igneous rocks cropping out in the Mullaley area into six groups is further validated by detailed petrography, mineralogy and chemistry. 1. The Garrawilla Volcanics, of late Triassic/ early Jurassic age, constitute a mildly alkaline, JUDITH M. BEAN low-K, high Fe,0,: FeO lineage; the alkali” olivine basalts, alkali basalts, hawaiites and mugearites are characterized by one feldspar— a plagioclase, and the soda trachytes by anortho= clase ; titanomagnetite is abundant in inter mediate rock types and the tendency to erupt explosively increased markedly with increasing evolution of the lavas. ( the fel 5° i J a pa <7 bre a, ) x ' ml 2 iB de mu att 2 4 6 8 T Naz0O Weight percent FiGuRE 6.—Generalized trend lines for variation o rd K,O against Na,O for rocks from Gough Island (Go), ti Nandewar Volcano (N) and the Bulga Complex, Jj} {lp Mullaley (triangles). Bulga phonolitic trachytes— i open triangles. i 2. The Nombi Extrusives, of similar late }} iii Triassic/early Jurassic age, are moderately J} tk strongly undersaturated, low-K, low-Al, low | iw total alkalis basanites ; analcime and nepheline | are prominent constituents. 3. The Glenrowan Intrusives are cistingaiaal as mildly undersaturated, moderately high- to |] }j high-K alkali dolerites and microsyenodolerites, |) ai with low-Al, low total alkalis and low Fe,O, hh FeO +Fe,0, ratios ; sanidine is prominent in |) a the microsyenodolerites, in association with |) % plagioclase, and occurs as the sole feldspar in the i} i evolved felsic phases. The modal percentage of |} % opaque mineral is lower than in the Garrawilla ta Volcanics and olivine ranges continuously in composition to at least Fagg. 4. The Napperby Limburgite is a unique rock | &: type characterized by high-K and a strong degree of undersaturation. Xenocrystic olivine | j is prominent. ' 5. The Tambar Trachybasalt is distinguished by high-K, low-Na, mild degree of under- saturation, high- -Al and high total alkalis. ie 6. The Bulga Complex is dominated by the evolved rock types phonolitic trachyte and | 3, phonolite ; trachyandesite and tristanite are” minor. It is proposed that the parental magma possessed a mild degree of undersaturation and | Apgotr, M. J., 1969. a moderately high- to high-K value. The phonolites and phonolitic trachytes represent dual differentiation trends, one towards Na- and me-enrichment and the other towards K- enrichment. The former trend was effected under hydrous, peralkaline conditions with oxygen fugacities either higher than, or at least decreasing at a slower rate than, those under which the K-enrichment trend was effected. Critical chemical parameters in distinguishing the Mullaley lineages are Al, K and Fe,O,: FeO+Fe,0O;. The levels of Al (and _ total alkalis) may correlate with fractionation of Mg-rich olivine and clinopyroxene in the parental magmas at pressures of x9 kb (ef. Green and Ringwood, 1967). Levels of K vary without relation to other major or minor elements ; the only correlation is that the K content may increase with a decrease in the age of the igneous activity ; this may in turn correlate with increasing stability of the Mullaley area. The parameter Fe,0,: FeO+Fe,O, (when reflecting magmatic Fe,0,: FeO+Fe,O,) is taken as an indicator of the oxygen fugacity in the magma. In rocks in which the ratio is high, olivine is minor or absent, the modal percentage of magnetite is high, and hydrous phases such as biotite and analcime appear ; the tendency of the lavas to erupt explosively increases as the ratio increases. Acknowledgements The author is grateful for a Commonwealth Postgraduate Scholarship. 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Miner., 42, 475. — jw wt oe | | | | | | | t | | | | | | | | | 1 | Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 147-156, 1975 Continental Reconstructions and the Distribution of Coral Faunas During the Silurian* JOHN PICKETT Introduction Modern theories of sea-floor spreading have given tremendous impetus to the elaboration of proposals for past configurations of continental masses ; palaeomagnetic studies have resulted in the production of an increasing number of palaeogeographic maps. This paper takes three of these maps and examines them in relation to the distribution of coral faunas of the Silurian period, with a view to both pointing out possible deficiencies in the reconstructions and to deter- mining possible regional distribution patterns or faunal provinces. The continental reconstructions used are those of Creer (1973) ; Rickard and Belbin (MS) ; and Smith, Briden and Drewry (1973). The latter is distinctively different from the others in the separation of Europe and Asia at the Urals. The configuration of Rickard and _ Belbin proposes a very close fit of all the continental Masses, without a conspicuous gap between Gondwanaland and Asia. The basis for producing this model differs slightly from the others, in that in addition to palaeomagnetic information, it draws on simple geometric fit ; the aim behind its production was to arrive at a condensed Pangaea. A probable result of this }is a greater proximity of many areas to the equator than is achieved by other methods. All three reconstructions point to a substantial southern landmass, with a considerable number of very much smaller land areas in the north. The distribution of hermatypic corals in present-day seas is controlled by two major constraints ; minimum temperature of the ocean waters and the availability of sunlight. Other Testrictions (e.g. turbidity, salinity) tend to be more local. Reef corals will not thrive in waters in which the temperature falls to 18°C for any length of time. The optimum temper- | ature is in the range 25°-29°C. They are thus | effectively restricted to a zone within the | latitudes 30°N and 30°S. * Presidential Address delivered to the Royal Society of New South Wales at Science House, Gloucester | Street, Sydney, on April 2, 1975. A most important feature of hermatypic corals is the presence of symbiotic algae within the tissues of the polyp. It is their presence which causes the restriction of hermatypic corals to the photic zone. Most coral polyps, which are carnivorous, feeding on plankton, are expanded only at night. This, coupled with the dependence of the polyps on their photo- synthetic symbionts, produces a very marked diurnal cycle in the physiological functions of the coral animals. It has been shown (Goreau and Goreau, 1959) that the uptake of calcium is greatest under clear, sunny conditions, and is reduced to 50% of this on a cloudy day, falling to 10% under conditions of total darkness. Because of this daily cycle, the skeletons of corals show tiny laminae corresponding to the daily skeletal increments. It is possible to observe these tiny growth lines on extremely well preserved fossil corals, the growth lines indicating that the rugose corals of the Palaeozoic era also enjoyed the benefits of symbiotic zooxanthellae. By detailed analysis of these daily increments on a Devonian coral, one colleague (Scrutton, 1965) concluded that the Devonian year consisted of 13 lunar months each of 304 days. Fossil calcareous algae, indicative of well-lit waters, are frequent associates of corals. It thus seems unlikely that the environmental constraints to which Palaeozoic corals were subject varied greatly from those governing present coral distribution. Geographical Distribution Initially, simply to examine the spread of , occurrences, known localities for corals during Llandovery, Wenlock and Ludlow times were plotted on the reconstruction of Smith, Briden and Drewry (1973) (Figures 1-3). Since the | distribution of corals is virtually identical for ° all three epochs, the information was grouped for the other two projections (Figures 4, 5). Reconstructions specifically based on Silurian palaeomagnetic data are almost unobtainable, since the data for this period seem particularly unreliable. The titles of the three selected for 148 JOHN PICKETT FicureE |.—Distribution of corals during the Llandovery. Reconstruction of Smith, Briden and Drewry, 1973. For all maps, stippling indicates probable land areas. Ss Ss SS Ss Ss = eS =. aS” s- FicuRE 2.—Distribution of corals during the Wenlock. Reconstruction of Smith, Briden and Drewry, 1973. DISTRIBUTION OF CORAL FAUNAS DURING THE SILURIAN i b y oon me ri > * p< J “ —_ 4 ara Pat / 2 ee har. vee SGM el FicurE 3.—Distribution of corals during the Ludlow. depicting Devonian ”’ the present data are ‘ Lower (Smith, Briden and Drewry), (Creer), and “‘ Pangaea’”’ (Rickard and Belbin). The latter was re-drafted for this paper using a polar position in present-day Angola, and covers a time interval including the Silurian. To facilitate appreciation of the differences between the three reconstructions, all have been presented on a Mercator projection, which, although not ideal for illustrating distribution of land masses, is useful when considering equatorial distribution such as might be expected with the corals. The distribution of corals during the early Devonian is rather similar to that during the Silurian, the disparity in age is not great, and the credibility of the reconstructions is greater than for the Ordovician. For these reasons the early Devonian palaeomaps have been selected as more nearly representing the Silurian situation. The most immediately obvious disparity in distribution is shown by the Japanese occurrences. In all three reconstructions, the islands of Japan occupy an extreme northerly position, varying from about 75°-90°N for the models of Creer and Smith ef al., to 40°-48°N for that of Rickard and Belbin. Occurrences in Asia, especially northwestern USSR, China and the Indo-Chinese area are in fairly high latitudes, certainly more northerly latitudes than those in which corals occur at present. “Silurian and very early Devonian ”’ cae Reconstruction of Smith, Briden and Drewry, 1973. The southern distribution is _ surprisingly consistent for the three reconstructions con- sidered. The coral occurrences all fall north of 40°S, with two exceptions, namely the Venezuelan localities of Scrutton (1971) and those in Algeria on the projection of Rickard and Belbin. The occurrence of Favosites argentina (Clarke, 1913; Hill, 1958) at Cerro del Fuerte in Argentina has been shown to be Devonian (Baldis, 1971). The report of Favosites magarensis from the Amazon Valley (Ruedemann in Maury, 1929) was regarded by Hill (1959) as doubtful ; it was not substantiated by Lange (1972), and certainly seems out of place in the succession he describes for the Trombetas Formation. In view of the fairly tropical situation of northern Africa on most reconstructions and the known occurrences of Silurian rocks in the region, the relative paucity of the faunas of that area seems somewhat anomalous. It may be that this is due to insufficient documentation rather than a real paucity of the faunas, however. The maps show no pronounced equatorial distribution of corals on any of the recon- structions examined. There is no immediate reason for assuming that the latitudinal distribution of Silurian corals was the same as that of the present ones. Relatively minor changes in either ocean temperatures or temperature-tolerance of the organisms could be responsible for substantial differences in 150 JOHN PICKETT eh Ne 5 : Fears a | Pe Ficure 4.—Distribution of corals during the Silurian. Reconstruction of Creer, 1973. Figure 5.—Distribution of corals during the Silurian. Reconstruction of Rickard and Belbin, MS, ba) ee | ) : | | DISTRIBUTION OF CORAL FAUNAS DURING THE SILURIAN distribution patterns. tribution which is worthy of note ; be further discussed later. It is the unequal dis- this will Provincialism The unevenness of information available from the many areas from which corals are known makes it very difficult to be quite positive about faunal provinces. The first step was to draw up a list of coral genera which are recognized within the Silurian, deleting those which are synonyms or whose validity is suspect. Even then the list presented here is not exhaustive, as some genera with very restricted distribution, which are probably still to be recognized elsewhere, have not been included. This applies to a number of the Russian tabulate genera, since taxonomists in countries outside the USSR have not devoted similar attention to this group. Table 1 shows those genera considered within this study. No discussion of synonymies is incorporated here; the list is however not conservative. Table 1 shows the distribution of genera in various areas. Ideally, a geographical analysis would be accompanied by a determination of the area in which each taxon originated, to determine migration directions. To do this for over 200 genera would be an unrealistic under- taking using present knowledge of stratigraphic ranges; the genera are therefore designated according to the country from which the type species was described, as follows : O Europe (Old World) N North America (New World) A Asia V_ Australia (Van Dieman’s Land) | J Japan + S South America In addition, those genera which occur in the ‘}ifour continents O, A, N, V are considered to }form part of a universal fauna and are designated U. These genera are most characteristic of }) Silurian coral assemblages throughout the world. { The aim of this operation was to derive a {formula for composition of the various local jfaunas (e.g. for Australia O,.N,;AgVgJ,Uss). {While the formulae so derived do reflect to a jcertain extent the affinities of the fauna, their lusefulness is very much a reflection of the jamount of work done in this area (e.g. Africa {0.U,) or simply of the abundance of its faunas. {A further disadvantage of this approach is that Ithere is no indication of what groups make a local fauna distinctive. The gross unevenness lof the data precludes any possibility of a useful | £E 151 result using computer or other statistical techniques (cf. Leleshus, 1972). For these reasons this approach was abandoned, and the data ultimately evaluated by setting out the genera geographically (Table 2), then examining , each genus individually for its usefulness as a provincial index. For this kind of analysis those genera which are known from a single locality, or are only recently described, may assume an exaggerated importance. Con- sequently it was desirable to use a number of criteria to determine the validity of the various genera in provincial analysis. The following are considered appropriate: (a) the genus should be both distinct and distinctive ; (b) it should form a reasonable component of the fauna ; (c) it must show some restriction in its distribution. In Table 2 those genera which are potentially significant according to these requirements are shown in italics. A chiefly western and northern province can be defined in broad terms, characterized by the genera Cystthalysites, Syringolites, the acer- vulariids Diplophyllum and Acervularia, Ditoecholasma, Entelophylloides, Chonophyllum, Goniophyllum, Holophragma, Mesofavosites, Palaeofavosites and Porpites. This province includes North America, Europe, and probably also northern USSR. A southern and eastern province including Australia, Japan, central and southeast Asia and India is less well-defined, characterized chiefly by the halysitids Schedo- halysites and Falsicatentpora. Also important in this province are Mucophyllum, the chono- phyllid Yassia, and possibly Holmophyllia. Not all reported occurrences of the Australian Mucophyllum are true representatives of that genus, those from the Baltic and possibly also elsewhere being much-thickened chonophyllids. Another Australian genus which, on a literature survey, would appear characteristic of the province, is Hattonia. This genus was recently shown to be exclusively Australian (Pickett and Jell, 1974); the central Asian species referred to the genus by various authors are probably a species group of the otherwise characteristically Devonian genus Dictyofavosites. It is also possible that Sparsisolenia Stasinska from Norway may prove to be a synonym of Hattonia. Although the southern and eastern province is less well-defined generically, a number of species which are common to Australia and parts of Asia offer evidence of faunal affinity: the Australian species Halysites cratus Etheridge fil. and Halysites sussmulchi Etheridge fil. in Japan ; Acanthohalysites pycnoblastoides yabet in China ; 152 JOHN PICKETT , od TABLE 1 1! Distribution of Silurian coral geneva. Column numbers : 1, Europe ; 2, western North America ; 3, eastern North America ; 4, Arctic North America ; 5, southeastern and eastern Asia ; 6, central Asia ; 7, northern Asia ; 8, Japan; 9, Australia ; 10, Africa ; 11, South America. For further explanation see text. . | DISTRIBUTION OF SILURIAN CORAL GENERA | [i fetstels[o|z{s]s]o[n| Acanthocyclus 4 iy Acanthohalysites Acervularia Adaverina Agetolites Alleynia Allotropiophy!lum Altaja Alveolites Amplexoides Amsdenoides Angopora Angullophy!lum Anisophyllum Antherolites Aphytlum Arachnophy!lum =e my ees Araeopoma an ie Ser ‘oe Sor ior iain fara bebe Sie bow Sous eas ie iy Seale Saul sre Sy Sr Aulocystella Aulopora Auloporella Australophy!lum Barrandeolites Barrandeophy|lum Bogimbailites ten Briantelasma Calostylis Camptolithus Cannipora Cantrillia Capnophy!lum Carinophy!lum Catenipora Ceriaster Chavsakia Chonophy!lum Circophy lium Cladopora Coenites Columnaxon Contortophy!fum Coronoruga Corrugopora Cosmiolithus Crassilasma Craterophyllum Cyathactis Cyathophylloides Cylindrostylus Cymatelasma Cymatella Cystihalysites Cystilasma Cystipaliphyllum Ss Fa Cystiphy!lum Daljanolites Dalmanophy!lum Denayphyllum } Densiphy!lum die Dentilasma : Desmidopora | kati Dinophy!lum ; Diplochone Prov Diploepora i Diplophy lium Paro Disphy!lum t if e i Ditoecholasma Dokophy!lum e ; Fury Duncanella : the Endophy!lum \ Entelophylloides id at th Entelophy|lum e \ :, Evenkiella e i | Expressophy!lum e Anst Falsicatenipora e { 7 Fasciphyllum e } | Favosipora . Favosites e | civil Fletcheria j apn Fomitchevia a: Fossopora f ‘ur Goniophy! lum t for Gissarophy!lum 2 Grabauphy!lum j iter Gukoviphy!lum | : Gyalophy!lum ‘ai Halysites t Hattonia tint, Hedstroemophy!lum Heliolites FCOEESPOvPOCZTYPOZrrPrOrrzZTOoOCOODOZTOOrP Ye ePEZKYPOCrORrPCCrOSeSC RPKECOCHEFOZFOP FOC <> Fr K< OPFOR Kr>> corals. In the present state of our knowledge, “endemic ’’ genera cannot be trusted as true indicators of provincialism. More reliable are groups which show a_ broader _ regional distribution. Leleshus (1972) is of the opinion that the lack of differentiation of Silurian faunas is a function of time : “ the Ludlovian provinces did not have time to form independent regions” (p. 74). The reason for this homogeneity is however not to be sought in terms of available time. The recent scleractinian faunas have developed as a result of the isolation of the Atlantic and Indo- Pacific provinces with the closing of the Tethys in the middle Miocene, a period of approximately 20 million years, only two-thirds of Silurian time. The real reason for Silurian distribution patterns as well as those of present seas is geographic. The present-day distribution is conditioned by the great meridional extensions of the Americas and the mass of Africa-Europe- Asia ; there is no possibility of migration from one area to the other. The Silurian geography was quite different from this, with a single large southern continent, a number of smaller land areas, and no great north-south obstructions to east-west migration of tropical faunas. The smaller land masses could act at best as a filter to migration, so that provincialism could only be weak. The faunas recently described from western USA (Merriam, 1972, 1973) are in some respects similar to those from eastern Australia. Arachnophyllum kayi Merriam is very similar to Zenophila walli (Etheridge fil.) (they are at least congeneric) ; Klamathastraea Merriam is possibly a junior synonym of Yassia Jones (McLean, 19746); and the Australian genus Mucophyllum occurs in California and Nevada, 154 Acanthohalysites Alveolites Arachnophyllum Aulopora Catenipora Cladopora Coenites Angullophyllum Australophyllum Coronoruga Allotropiophyllum Amsdenoides Anisophyllum Auloporella Briantelasma Camptolithus Cannipora Capnophyllum Acanthocyclus Aceyvularia Adaverina Alleynia Angopora Araeopoma Carrandeophyllum Calostylis Cantrillia Chonophyllum Circophyllum Cosmiolithus Cyathophylloides Cymatelasma Dalmanophyllum Densiphyllum Desmidopora Diplochone Diploepora Agetolites Altaja Amplexoides Antherolites Aphyllum Aulocystella Barrandeolites Bogimbailites Carinophyllum Ceriaster Chavsakia Contortophyllum Crassilasma Cylindrostylus Cymatella Cystihalysites Cystilasma Cystipaliphyllum Daljanolites JOHN PICKETT TABLE Geographical lists of genera according to the type locality of the type species. 2 “= in provincial analysis are shown in italics. Universal Fauna Cyathactis Kodonophyllum Cystiphyllum Multisolenia Entelophyllum Palaeocyathus Favosites Palaeophyllum Halysites Phaulactis Heliolites Planalveolites Holmophyllum Plasmopora Australia Fossopora Mazaphyllum Hattonia Mictocystis Loyolophyllum Mucophyllum Japan South America Falsicatenipora Columnaxon Kitakamiphyllum North America Corrugopora Hexismia Craterophyllum Oliveria Denayphyllum Ptychophyllum Diplophyllum Pseudocryptophyllum Ditoecholasma Pycnostylus Duncanella Romingeria Entelophylloides Shastaphyllum Grabauphyllum Stylopleura Europe Disphyllum Lykocystiphyllum Dokophyllum Mastopora Endophyllum Mesofavosites Fasciphyllum Microplasma Favosipora Multithecopora Fletcheria Nodulipora Goniophyllum Pachypora Gukoviphyllum Palaeofavosites Gyalophyllum Pilophyllum Hedstroemophyllum Porpites Helminthidium Protaraea Holophragma Pycnactis Ketophyllum Pycnolithus Kiaerites Rhabdacanthia Kyphophyllum Rhabdocyclus Laceripora Rhegmaphyllum Laminoplasma Rhytidophyllum Lamprophyllum Saaremolites Leolasma Schlotheimophyllum Asia Dentilasma Miculiella Dinophyllum Moyerolites Evenkiella Neomphyma Expressophyllum Neopaliphyllum Fomitchevia Palaearaea Gissarophyllum Palaeocorolites Helioplasma Paliphyllum Helioplasmolites Parastriatopora Hemiagetolites Pilophylloides Hillaepora Placocoenites Holomophyllia Plicatomurus Immenovia Proheliolites Implicophyllum Protopilophyllum Koreanopora Pseudophaulactis Maikottia Pseudoplasmopora Medinophyllum Pseudoplasmoporella Mesosolenia Rukhinia Microconoplasma Ryderophyllum Micula Salairia Genera which ave potentially useful OR at Ameee' g Propora Rhizophyllum Streptelasma Striatopora Syringopora Thamnopora Tryplasma Saucrophyllum Schedohalysites Yassia / Tonkinaria f Toquimaphyllum Trachypora ; Wintunastraea Scoliopora \ Solenihalysites Sparsisolenia Spongophylloides Spongophyllum Squameofavosites Stanleysmithia Stauria Stelliporella Stereoxylodes Stortophyllum Strombodes Subalveolites Syringaxon Thecia Weissermelia Wenlockia Xiphelasma Zelophyllum : Syringolites : Salairipora Salairophyllum Sapporipora Scyphophyllum Somphopora Soshkinolites Spumaeolites Squameolites Subalveolitella Syringoporinus Tabularia Taxopora Tenuiphyllum Thaumatolites Thecaspinellum Thecipora Zeravschania i SS ee ee ’ ‘& 5 TRS Ae RE es 6s. fl DISTRIBUTION OF CORAL FAUNAS DURING THE SILURIAN though not elsewhere in the United States. The two areas concerned were, according to all reconstructions, separated then as now by the open sea ; it would therefore not be surprising to find faunal similarities on both sides of a proto-Pacific ocean, just as there are at the present time. Brachiopod Provinces In a number of important papers, a regional pattern in Silurian brachiopod faunas has been described (Cocks, 1972 ; Cocks and McKerrow, 1973; Boucot and Johnson, 1973). Of particular interest is the definition of the Clarkeia community, which has a restricted distribution in Africa and South America. This is considered to be a cold-water fauna by Cocks and McKerrow. Probable early Silurian (or latest Ordovician) glacial deposits are also known from the areas in which the Clarkera community occurs (Bolivia and Argentina : Berry and Boucot, 1972 ; North Africa : Sougy and Lécorché, 1963, Destombes, 1968 ; South Africa: Cocks et al., 1970). The distribution of these faunas appears somewhat anomalous for a supposed cold-water assemblage when plotted on a palaeogeographic map (see Cocks and McKerrow, 1973, text-fig. 3), as the most northerly locality, in the western Sahara, falls at 30°-40°S. The significance of this will be discussed later. No northern assemblages corresponding to the Clarkeia fauna have been recognized. Synthesis The observed distribution of Silurian coral occurrences is generally inconsistent with an expected equatorial distribution. Of the three palaeogeographic reconstructions reviewed, the best fit of the data is shown by the Rickard and Belbin model, on which all occurrences lie between 45°N and 45°S. Some of this restriction must be ascribed to the density of the recon- struction. The other two models show an anomaly confined chiefly to the northern hemisphere. It could be argued that the near-universal distribution of coral faunas on the Creer and Smith e¢ al. reconstructions points to widespread warm conditions during the Silurian, were it not for the presence in the southern hemisphere of the cold-water Clarkeia fauna. The distribution of corals in the southern area ties in well with the observed brachiopod distribution. It is perhaps significant that the apparently poor Silurian coral faunas of North Africa should occur north of the most northerly occurrence of the Clarkeia fauna. These occurrences lie just off the western coast of the southern continent 155 of Gondwana ; the northward extension of the cold-water brachiopod fauna and the absence of corals in relatively low latitudes may have been due to a cold current which flowed northward along the western margin of Gondwanaland. This situation is analogous to that of the present- day Humboldt current off the west coast of South America, which has a pronounced cooling effect as far north as the equator itself. In contrast to this situation are the observed data from the northern hemisphere, where no cold-water faunas have been defined ; instead, we find reef-building corals in areas immediately around the pole (Japan). It is quite illogical to expect that there was an Antarctic cold region without a similar Arctic one ; the explanation of the Asian situation must therefore be sought elsewhere. The Rickard and Belbin model does not accord well with such a proposal. Firstly, the north African coral occurrences lie 20°-25° further south than on the other reconstructions, which alone would suffice to explain their impoverished nature, and the proximity of the cold-water brachiopod fauna. In addition, however, the N-S trend of the coastline has _ largely disappeared ; the localities of both the Clarkeia fauna and the corals: would lie east of the influence of any north-flowing cold current. Similarly, though, the locale implied for the cold-water fauna may well have been too warm. If we examine the areas of Gondwanaland, Euramerica, and Asia, it becomes apparent that, although the Euramerican and Gondwana land- masses have suffered marginal tectonism, their central portions have remained virtually unaffected since at least the Middle Palaeozoic. This is in complete contrast to the situation in Asia, which is almost surrounded by areas of substantial Tertiary movement, contains at least two large belts of great Mesozoic activity, and is divided into two by a very broad belt of Hercynian folding (this situation is well illustrated by Smith, Briden and Drewry, 1973, text-fig. 12). It follows that any consideration of the Asian area as a unit, even for Early Mesozoic times, and most certainly for the Mid-Palaeozoic, will lead to erroneous results. The distribution of corals and the absence of northern cold-water faunas suggests that none of the present land-masses was in the Arctic during the Silurian. The similarity of the Japanese faunas with those of Australia suggests that Japan at that time was much closer to Australia than shown on present reconstructions. Similarly, affinities between other faunas in Asia and those of Australia point to a position generally in the same area. 156 JOHN Conclusions 1. The distribution of the Silurian corals favours the reconstruction of Rickard and Belbin. This however is still subject to other conditions, notably that under (2) below, and the anomalously close positions of cold-water faunas in Mauritania and tropical ones in Algeria and Morocco. 2. The composite nature of the Asian continent makes it impossible to consider it a single unit, at least for the time interval under discussion. A final reconstruction will probably show Japan much nearer to the Australian area. 3. It is probable that none of the present continents lay in the Arctic area during the Silurian. 4. Faunal distribution in the southern hemisphere was probably influenced by a cold current which flowed northwards along the west coast of Gondwanaland. 5. Provincialism in corals during the Silurian was weak, largely due to the absence of substantial north-south trending geographical barriers. References Ba.pis, B. A. J., 1971. La Posiciédn Estratigrafica de Favosites argentinus Thomas. | | aii A Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 157-167, 1975 Some Early Cretaceous Organic-walled Microplankton from the Great Australian Basin, Australia RoGER MorGAN ABSTRACT—Four new genera and seven new species of organic-walled microplankton are described. Two genera and five species are fossil dinoflagellate cysts, and two monospecific genera are of uncertain biological origin. The dinoflagellates Diconodinium davidii, Spinidinium boydii and Bourkidinium granulatum and the acritarch Nummus monoculatus are useful biostratigraphic forms in the marine part of the section. Introduction _ Early Cretaceous microplankton of the Great Australian Basin are not well known despite the principally taxonomic papers of Cookson and Eisenack since 1958, and the principally biostratigraphic papers of Evans (1966a—b) and Burger (1973 and in press). With a few exceptions, the stratigraphic distributions of microplankton species are particularly poorly known. On the other hand, the stratigraphic distribution of many spore and pollen species are well known (Dettmann, 1963; Dettmann and Playford, 1969). The purpose of the present contribution is to introduce seven new species which are considered important to the understanding of the micro- plankton palynostratigraphy of the Great Australian Basin, and to discuss their palaeo- environmental significance briefly. A locality map of the boreholes mentioned is presented as Figure 1. In quoting dimensions of the species described, the following convention is followed throughout : The first number is the minimum, the bracketed number the mean, and the third number the maximum dimension. Systematic Palaeontology Class DINOPHYCEAE Cyst-Genus Diconodinium Eisenack and Cookson 1960 Type species Diconodinium multispinum (Deflandre and Cookson, 1955 p. 257, Plate 1, Figure 5) Eisenack and Cookson, 1960 p. 3. The dinoflagellates Fusifovmacysta salasii and Batia- casphaera macrogranulata and the acritarch Micvofasta evansii are useful biostratigraphic and palaeo-environmental indicators in the non-marine and transgressional part of the sequence. The archeopyle problem in Diconodinium is discussed, and some specimens previously assigned to D. multispinum (Deflandre and Cookson) are redescribed. The generic description of Batia- casphaera is emended to expand the range of ornament types. Diconodinium davidu sp. nov. (Plate I, Figures la—b, 2a—d) Description : Cyst consists of a broadly subtriangular epitract bearing a long steeply conical, distally truncate apical horn, and a broadly rounded hypotract bearing a single strong, sharply pointed antapical horn slightly offset from the longitudinal axis. The cingulum is about 5 uw wide, and offset slightly at the sulcus. The autophragm bears a moderately dense cover of small solid spinulae or clavae about 1-0-1:5 u high and about 1-0 uw thick. These are absent from the cingulum and rare on the sulcus area, but otherwise cover the entire autophragm. The spinulae or clavae may be randomly distributed but are more often, at least partly, aligned in rows to reveal traces of tabulation, and are always aligned in two rows along the margins of the cingulum. [If aligned, the peri- tabular spinulae or clavae are larger and stouter than the intratabular ones. On some specimens, most of the clavae are peritabular with few or none intratabular. The archeopyle is type la or IPa. The former type results when only the lateral and apical sutures of the reflected 2a plate open, and the plate remains attached antapically to the 4” reflected plate. Commonly, the lateral sutures of plate 4” at least partly open, so that the operculum consists of a single piece (comprising plates 2a and 4”) that remains attached at, or close to, the cingulum. Dimensions : 72 (83) 96 uw long and 41 (50) 57 w broad (10 specimens measured). 158 Holotype : Plate I, Figure 1: 80 u long and 47 yw broad. M.M.M.C. 2001. Comparison : This species is similar to Duconodinium arcticum Manum and Cookson which has shorter horns, less dense and finer ornament (minute granules up to 0-5 uw in diameter rather than spinulae or clavae 1:0-1:5 uw high and R_ Rakich Bore Ya about 1p in diameter) and is smaller (50-73 u long, 32-53 w broad rather than 72-96 uw long and 41-57 w broad). D. pusillum Singh (1971) differs from the new species by having shorter horns, finer, sharply pointed spines 0-5 yu long and by being smaller (40 (47) 54 u long and 28 (36-5) 43 wu broad). D. firmum Harland (1973) can be distinguished by its small size (36-0 (42-7) 50-0 uw long and 18-0 (29-3) 30 uw broad), solid (not hollow) apical horn, fine granulation (no size given), thin wall and broad cingulum. A precingular archeopyle may be present in D. firmum. Diconodinium pelliferum (Cookson and Eisenack, 1958) (85 uw long and 59 u. broad) L Lake Phillipson Bore O Santos Oodnadatta DDH 1 K Kalladeina Water Bore Yo SADM Yalkalpo DDH 1 Wa NSWDM_ Wanaaring DDH 1 NSWDM_ Yantabulla DDH 1 B NSWDM Bellfield DDH 1 We NSWDM Weilmoringle DDH 1 Fic. 1 | ROGER MORGAN i and Diconodinium dispersum (Cookson and Eisenack, 1958) (64-90 p long and 38-62 uw broad) are similar in size to D. davidii (72-96 long and 41-57 uw broad). Surface ornament in D. pelliferum consists of long (1:0-2-:5 uy) sharply pointed spines, and in D. dispersum of long (2-0-3-0 w) strongly capitate spines, while the new species has blunt non-capitate spinulae or clavae (1-0-1-5 u long). ee 7 The species most similar to D. davidii is Diconodinium multispinum (Deflandre and Cookson, 1955). The holotype of the latter _ species is very different from the described and — figured specimen assigned to Palaeohy- | strichophora multispina by Cookson and — Eisenack (1958) and subsequently transferred — to Diconodinium by Eisenack and Cookson | (1960). I have examined the latter specimen — but not the holotype of D. multispinum. In — general, the name seems to be applied to forms — with the following features: broadly fusiform — cyst having a narrow cingulum that divides the — cyst approximately equally ; a short apical and — ————————————— EARLY CRETACEOUS ORGANIC-WALLED MICROPLANKTON a single antapical horn; autophragm bears a dense covering of small granulae or short spinulae (about 0-5 uw long and broad), that are rarely aligned. From this concept the new species differs by having longer horns and coarser, less dense ornament. Strictly, the name D. multisbinum should be applied to the morphologically and _ time-stratigraphically distinct holotype. A new name would then be necessary for the forms assigned by Cookson and Eisenack (1958) to Palaeohystrichophora multispina. Taxonomic changes await study of the holotype. The new species differs from most other described species of Dzuconodinium by the possession of an archeopyle, and from all species, other than those mentioned herein, by type of surface ornament, and by overall shape. Distribution : (Holotype locality is marked (H), paratype locality (P). This convention is followed throughout). Upper C. hughesii subzone Santos Oodnadatta No. 1 ; 232-4m, 244-0m SADM DDH Yalkalpo No. 1; 99-5 m, 114-5 m NSWDM DDH _ Weilmoringle 219-9 m (P) NSWDM DDH Bellfield No. 1; 158-0 m (H), 120-2 m Kalladeina Water 1,049-2 m NSWDM DDH Yantabulla No. 1 ; 122-0 m NSWDM DDH Wanaaring No. 1 ; 184-5 m C. striatus subzone SADM DDH Yalkalpo No. 1; 89 m NSWDM DDH Bellfield No. 1 ; 59-8 m NSWDM DDH Yantabulla No. 1; 92-1 m C. paradoxa zone Santos Oodnadatta No. 1; 164-7 m | Common in the upper C. hughesii subzone | (Aptian) of Dettmann and Playford (1969), with occasional specimens in the C. striatus subzone and C. parvadoxa (Albian) zone. No. 1; Bore 1,101:1 m, | Cyst genus Spinidiniwm Cookson and Eisenack, 19625 | Type species Spinidinium styloniferum Cookson | | and Eisenack, 1962b p. 489, Plate I, Figures 1-5 | | : : | : | Spinidinium boydii sp. nov. (Plate I, Figure 3a—d) | Description : Cyst is very broadly fusiform in dorsal-ventral | view. The apical horn is broadly conical and 159 distally truncate. A single, small broad, pointed antapical horn is present and is offset only slightly from the longitudinal axis. The sides are smoothly convex as there is no prominent cingular furrow. The surface ornament consists of relatively sparse solid granulae to truncate spinulae, (usually about 1-3 yw long and 0-5 uw thick) that are aligned in rows. Tabulation is defined by the alignment of the ornament, mostly peritabular with few intratabular granulae or spinulae. The cingulum and sulcus are always devoid of ornament. Alignment may define reflected plate outlines only weakly, with apparently random granulae or spinulae scattered over most of the periphragm, except for the cingulum and the sulcus. Both endophragm and periphragm are thin, and always separate at the base of the apical and the antapical horns. The archeopyle is intercalary, type Ia (2a only); the operculum is attached antapically. Comparisons : Spimdinium vestitum Brideaux 1971, differs from this species by having an angular pentagonal outline due to the much longer horns, and by bearing ornament consisting of cones and spines. Separation of the wall layers at the horns is absent in S. vestitum. Spinidinium styloniferwum Cookson and Eisenack, 1962) differs from this species by having more strongly developed horns, a deep cingular furrow, thicker wall layers, and much denser, stouter ornament. Dimensions : 41 (49) 72u long and 33 (42) 66 u broad (10 specimens measured). Holotype : Plate I, Figure 3 ; 47 p long and 37 u broad. M.M.M.C. 2002. Distribution : Upper C. hughesii subzone Kalladeina Water Bore 1,101:1 m, 1,049 -2 m, 1,036-1 m NSWDM DDH Yantabulla No. 1; 154-0 m C. striatus subzone NSWDM DDH Weilmoringle No. 1 ; 99-1 m, 132-1 m NSWDM DDH Bellfield No. 1; 39:7 m, 101-3 m (H) Kalladeina Water Bore, 1,005-6 m, 988-2 m NSWDM DDH Yantabulla No. 1; 53-4 m NSWDM DDH Wanaaring No. 1; 95-5 m, 122-0m Lower C. paradoxa zone Kalladeina Water Bore, 886-0 m NSWDM DDH Wanaaring No. 1 ; 53-4 m 160 Ranges from upper C. hughesi subzone (Aptian) of Dettmann and Playford (1969), is very common in the C. striatus subzone, and rarely occurs in the C. paradoxa (Albian) zone. Spinidinium styloniferum Cookson and Eisenack, 1962b (Plate II , Figure la-e) 1962b Spinidinium styloniferum Cookson and Eisenack p. 489, Plate 1, Figures 1-5 Revised Description : Cyst is thick walled, outline roughly pentagonal in_ dorsal-ventral view. The periphragm is drawn out into a broadly conical, distally truncate apical horn, a steeply conical, distally pointed left antapical horn, and a weakly developed right antapical horn. The cingulum is broad, divides the cyst into about equal parts, and is only offset slightly at the sulcus. The endophragm is approximately ellipsoidal ; the two wall layers separate slightly at the base of the horns. The periphragm bears many solid rod-like projections with broadly rounded distal ends. The rod-like ornament is occasionally 2-5-5-0 w long and 1-0-1-5 uw diameter, but more commonly is 2-0-4-0 u long and 0-5-1-0 win diameter. The ornament is closely spaced and aligned along the cingulum margins, and peritabular to the reflected plate areas. Some specimens have dense intratabular ornament as well; all specimens lack ornament on the cingulum and sulcus. The archeopyle is intercalary, type la (2a only) elongate trapezoidal; the archeopyle is attached along the antapical margin. Dimensions : 43 (49) 62 u long and 33 (40) 49 uw broad (10 specimens measured). Holotype : Plate II, Figure 1 ; 57 w long and 43 pu broad. P 21271. Type locality : Rakich’s bore, Caversham, Perth Basin between 350-355 ft., cuttings sample containing mixed Aptian-Albian assemblage. Comments : Recent re-examination shows that the holotype bears very coarse and dense ornament- ation, the maximum size ot which approximates that given above. Examination of other specimens on the slide containing the holotype and topotypic material shows that specimens with finer and less dense ornamentation are more typical. The angular outline, deep cingular furrow and presence of pericoels are ROGER MORGAN ; constant features. No specimens exactly like Jj i! the holotype have yet been observed trom the § i Great Australian Basin, but frequent specimens 9} a’ identical with the less heavily ornamented specimens from the type locality do occur, often in association with specimens of Spindinium boydit. Distribution : C. striatus zone : i 7 NSWDM DDH Weilmoringle No. 1 ;99-1 mj i 132-1 m NSWDM DDH Bellfield No. 1; 101-3 m, 59-8 m C. paradoxa zone Santos Oodnadatta No. 1 at 164-7 m Occurs most commonly in the C. striatus (Aptian-Albian) subzone of Dettmann and Playford (1969), with occasional specimens into | the C. paradoxa (Albian) zone. Cyst-genus Bourkidinium gen. nov. Type species Bourkidinium granulatum sp. nov. Description : Cysts are chorate, elongate ellipsoidal, and bear long, hollow, tubular processes which are restricted to the apex and antapex (probably | associated with only the apical and antapical | series’ of reflected plates). The low relief surface | ornament shows no evidence of a cingulum or | tabulation. The archeopyle is apical, type A. | Comparison : This genus differs from Tanyosphaeridium | Davey and Williams, 1966 by having processes_ present only at the apex and antapex. Stratigraphic occurrence : Restricted to the ?Late Aptian and Earl Albian of Australia. Bourkidinium granulatum gen. et sp. nov. (Plate II, Figure 2a—c) Description : Chorate cyst is elongate ellipsoidal and be long, hollow, distally flared processes arrange in two groups, one at the apical, and the other at the antapical, end. The number of process is variable, but there are always more in th antapical group (9-15) than in the apical group (4-7). The processes are 23-30 uw long, 1:0- | 2-5 win diameter, cylindrical or sightly tapering — towards the distal end, which is strongly flared, 5 slightly recurved with serrate margins, and 5-6 uw in diameter. The body, which is about 45 w long and 25 yw in diameter, is densel So Spm =] Se eS eS =. Sse ®)granulate and lacks indications of a cingulum Hior tabulation. The archeopyle is apical, type A, and all, or all but one or two, of the apical group of processes are on the free operculum. Comparison : This species is easily recognized by the unusual Idistribution of the processes. In both Tanyo- sphaeridium isocalamus (Deflandre and Cookson, 1955) and T. variecalamum Davey and Williams, 1966, that have ellipsoidal bodies, the processes jare distributed more or less uniformly on the wijcyst, and their distal ends are not widely jexpanded distally as in Bourkidinium granu- atum. Dimensions : wm) Central body 35 (46) 62 uw long and 20 (24) $29 u. broad, (10 specimens measured). W| Holotype : | Plate II, Figure 2 central body 62 uw long and 1/29 u broad. M.M.M.C. 2003. | Distribution : | C. striatus subzone i | NSWDM DDH Wanaaring No. 1; 95-5 m NSWDM DDH Weilmoringle No. 1; 133-6 m, 99-1 m (H) r NSWDM DDH Bellfield No. 1; 101-3 m, 59-8 m y SADM DDH Yalkalpo No. 1; 86-25 m | Low C. paradoxa zone a NSWDM DDH Wanaaring No. 1; 53-4 m ®) Restricted to the C. striatus subzone (Late Aptian or Early Albian) of Dettmann and Playford (1969) and lower C. pavadoxa zone § (Albian). in Cyst-genus Fusiformacysta gen. nov. Type species Fusiformacysta salasii sp. nov. i | Description : _ Cysts are fusiform with bluntly rounded, | tapered apical and single antapical horns. The autophragm is ornamented with low relief }features (scabrate to punctoreticulate). Archeopyle is precingular, type 2P-?5P, and the operculum is free. | Comparison : ‘ | This genus is similar in shape to Svalbardella | Manum 1960 and to Palacocystodinium Alberti §| 1961. These genera differ from Fusiformacysta }) by being cavate and by possessing an intercalary #)| rather than a precingular archeopyle. Svalbar- §) della and Palaeocystodinium are restricted to the ! | Uppermost Cretaceous and Tertiary, while }) Fusiformacysta is so far restricted to the earliest fl | | | }) Cretaceous. | | Stratigraphic occurrence : | Restricted to the Neocomian of Australia. i EARLY CRETACEOUS ORGANIC-WALLED MICROPLANKTON 161 Fustformacysta salasu gen. et sp. nov. (Plate II, Figures 4a—c, 5a—b) Description : Cyst is fusiform with long conical apical and single antapical horns which have bluntly rounded tips. The horns are similar in size and shape, the antapical horn sometimes being shorter ; each is equal to about one quarter of the total cyst length. The autophragm shows no trace of tabulation. The cyst contains no inner body. The archeopyle is large, pre- cingular, and formed by the loss of two to perhaps five individually separating reflected plates. The cyst is usually bent in the area near the archeopyle, so that the longitudinal axis is rarely straight. Dimensions : 107 (123) 152 w long and 33 (43) 51 uw broad (10 specimens measured). Holotype : Plate II, Figure 4 incomplete specimen 127 up long and 51 up broad. M.M.M.C. 2005. Comparison : This species differs from other fusiform cysts by having an autophragm, a large precingular archeopyle and a fine, uniform granulation. Distribution : Low C. stylosus zone SADM DDH Yalkalpo No. 1 ; 211-46 m Kalladeina Water Bore, 1,162:7 m, 1,168-2 m, 1,184:9 m NSWDM DDH Wanaaring No. 1; 389-2 (H) (P) Rios NSWDM DDH _ Weilmoringle No. 1; 435-2 m The species is rare in all localities, but occurs consistently low in the C. stylosus zone of Dettmann and Playford (1969) and is therefore early Neocomian in age. Cyst-genus Batiacasphaera Drugg 1970 Type species Batiacasphaera compta Drugg 1970, p. 813-814, Figures 6 A-E, 7 A-B Emended description : Cysts subspherical to lenticular, with an angular apical archeopyle of type A. Ornament consists of positive elements which may be separate, or fuse to form rugulae or a reticulum. Membranous ornament and tabulation are absent. Comparison : This genus differs from Canningia Cookson and Eisenack, 1960 in that the latter exhibits antapical horns. The overall shape _ of 162 Batiacasphaera is similar to Cassiculosphaera Davey 1969, which has membranous reticulate ornament, Cassidium Drugg 1967, which has a tabulate rugulate wall, and Chytroeisphaeridia (Sarjeant, 1962) Downie and Sarjeant, 1964 emend Pocock 1972, which lacks ornamentation. Batiacasphaera macrogranulata sp. nov. (Plate II, Figure 3a—d) Description : In dorso-ventral view, specimens are sub- circular in outline, lacking an apical protrusion. Autophragm bears a medium dense cover of low, flat, solid, granulae, that are about 1-5 w in diameter, or has short rugulae formed by the coalescing of two or more adjacent granulae. The density of granulae is variable; some specimens bear mostly granulae and few rugulae, while others bear almost entirely rugulae. The surface between the granulae or rugulae is psilate. The archeopyle is apical, type A, operculum free; the six precingular reflected plates and the sulcal notch are distinguishable by the partial opening of the accessory archeopyle sutures. The sulcal notch is always offset from the midline, as the shape of the cyst is lenticular. Dimensions : 49 (53) 60 uw long and 49 (55) 69 uw broad (10 specimens measured). Holotype : Plate II, Figure 3 ; 60 uw long and 69 y. broad. M.M.M.C. 2004. Comparison : The new species differs from Batiacasphaera compta Drugg 1970, which has fine reticulate to foveolate ornament, and from Batiacasphaera baculata Drugg 1970, which has fine granulae and rod-like tuberculae covering the surface. Comment : The new species is common in assemblages lacking other dinoflagellates or containing only a few other forms. With only superficial examination it may be misidentified as a damaged baculate spore. Distribution : C. stylosus zone SADM DDH Yalkalpo No. 1; 211-46 m Kalladeina Water Bore; 1,162-7m, 1,184-9 m NSWDM DDH Wanaaring No. 1 ; 348-0 m, 389-2 (H) NSWDM DDH _ Weilmoringle 352-0 m, 435-2m . INOF eis; ROGER MORGAN zone of Dettmann and Playford (1969), and is ; Occurs throughout the Neocomian C. stylos | dhl the most frequent dinoflagellate in some samples, : ; Group Acritarcha Evitt Acritarch genus Microfasta gen. nov. Type species Microfasta evansii sp. nov. Description : i A small, cylindrical ring-shaped acritare whose diameter usually exceeds its widt The ring may be variously ornamente Stratigraphic occurrence : Restricted to the Neocomian and Lower | Aptian of Australia. | 0 it Microfasta evansu gen. and sp. nov. | A (Plate III, Figures 2a—d, 3) i 1960 Gen. et sp. indet. FORM A Eisenack an | a Cookson p. 10, Plate III, Figures 12-14 a] ani Description : | - Band-like acritarch is made up of a series of long, hollow, cylindrical chambers running | lengthways across the ring, and arranged side by side around the ring. The chambers are closed at both ends, and their walls are usually | slightly crenulate and finely granulate. The | sides of the ring, at which the chamber ends are | closed, are usually thickened, and form solid — edges. Frequently, the delicate cylindrical — chambers are damaged, and only small fragments | of the membrane adhere to the ring. In such cases ridges with small fragments of membrane mark the position of the pre-existing cylinder | walls. Dimensions : Diameter 20 (30) 37 w and width 6 (11) 12 p | (10 specimens measured). Holotype : and Plate III, Figure 3; 30 uw in diameter and |} 12 uw wide. M.M.M.C. 2009. mR Cy Comment : I As stated by Eisenack and Cookson (1960), the biological affinities of this form are com- pletely unknown. However, it is extremely distinctive and widespread in Australian Neocomian sediments containing limited micro- plankton assemblages. Burger (in press) has expressed the opinion — that these ring structures may be arranged in ~ life to form long filaments with the heavy — EARLY CRETACEOUS ORGANIC-WALLED MICROPLANKTON thickening marking the lines of fracture between adjacent rings. Distribution : C. stylosus zone NSWDM DDH Yantabulla No. 1 ; 274-2 m NSWDM DDH Wanaaring No. 1 ; 389-2 m, 348-0 m (H), 317-8 m SADM DDH Yalkalpo No. 1; 190-72 m, 202-30 m Lower C. hughesii subzone NSWDM DDH Bellfield No. 1; 220-5 m NSWDM DDH Weilmoringle No. 1; 320-6 m NSWDM DDH Yantabulla No. 1 ; 247-7 m NSWDM DDH Wanaaring No. 1 ; 290-7 m Lake Phillipson Bore, South Australia 26-8 m (P). This species is widely distributed and common in the late C. stylosus zone (Neocomian) and early C. hughesii subzone (Neocomian—Aptian) of Dettmann and Playford (1969). Also recorded by Eisenack and Cookson (1960) from similar levels (Late Neocomian and Lower Aptian) of the Carnarvon, Carpentaria and Eromanga Basins, by Evans (1966a) in the Carpentaria and Surat Basins, and by Evans (1966)) from the Gippsland and Otway Basins, this species appears to be a very useful biostratigraphic marker. I have _ recently recorded this species from the same biostrati- graphic level in the Perth Basin (unpubl.). In some samples, it is the dominant microplankton species. Acritarch genus Nummus gen. nov. Type species Nummus monoculatus sp. nov. Description : Lenticular fossil is single-walled, with a slight thickening around the margin in dorsal- ventral view. A subcircular to rounded angular pylome is located in an “ intercalary ’’ position, and most of the “ventral’’ wall is lost, apparently by disintegration. Comparison : This genus differs from Cyclopsiella Drugg and Loeblich 1967, by having a single wall layer instead of two, and by the “ disintegrating ” instead of solid, ventral wall. Lecaniella Cookson and Eisenack 1962a, Paralecaniella Cookson and Eisenack 1970, Eyrea Cookson and Eisenack, 1971 and Epicephalopyxis Deflandre 1935, all lack a pylome. Stratigraphic occurrence : Restricted to the Aptian of Australia. 163 Nummus monoculatus gen. et sp. nov. (Plate III, Figures la—d, 4a—c) Description : Single walled fossil is lenticular in shape, with a slight thickening around the subcircular margin in dorsal-ventral view. A moderately large subcircular to rounded angular pylome is located in an “intercalary”’ position on the “ dorsal”’ side, halfway between the margin and the centre of the fossil. The ‘‘ dorsal ’’ wall is of moderate thickness, and is granulo-punctate. The ventral wall is very thin, granulopunctate and generally almost completely disintegrated. Some specimens have most of the ventral wall intact, while others have small remnants of ventral wall clinging to the marginal thickening which marks the junction of dorsal and ventral sides. As most specimens. are _ slightly compressed, the margins are usually folded in an irregular manner. A ‘“‘cingulum’’ may be suggested beneath the pylome on the dorsal side by a fold, or by a line of slightly coarser ornament. Dimensions : 35 (46) 55 uw long and 31 (39) 43 uw broad (10 specimens measured). Holotype : Plate III, Figure 1 ; 45 uw long and 41 pu broad. M.M.M.C. 2007 Comparison : The new species differs from Cyclopsiella elliptica’ Drugg and Loeblich, 1967 and Cyclopsiella vieta Drugg and Loeblich, 1967 by having a single wall layer instead of two, and by having a disintegrating “ ventral ’’ wall. Distribution : Lower and mid C. hughesit subzone NSWDM DDH Yantabulla No. 1; 184°:2 m NSWDM DDH Wanaaring No. 1 ; 290-7 m, 257-4 m (P) NSWDM DDH Weilmoringle No. 1 ; 284 m Santos Oodnadatta No. 1 ; 264-4 m, 256-8 m SADM DDH Yalkalpo No. 1; 180-71 m, 156-52 m, (H) 155-2 m, 148-30 m C. striatus subzone NSWDM DDH Yantabulla No. 1; 53:4 m NSWDM DDH Wanaaring No. 1; 154-3 m SADM DDH Yalkalpo No. 1 ; 89 m, 86-25 m Occurs rarely to very frequently in the early and mid C. hughesii subzone (Late Neocomian to Aptian) of Dettmann and Playford (1969), is absent from the late C. hughesii subzone, and occurs rarely, apparently reworked in the C. striatus subzone (Late Aptian or Early Albian). 164 Discussion The sequence of microplankton (dinoflagellate and acritarch) floras that can be recognized along the southern margin of the Great Aust- ralian Basin lies outside the scope of the present contribution and will be discussed fully in a later paper. The biostratigraphic significance of the present species can be best evaluated when compared with the spore and pollen zones of Dettmann and Playford (1969). A summary is presented as Figure 2. The palaeoenviron- mental evaluation of the present species rests in part on the work of Harris (1973). spore—pollen zonations Dettmann and Playford 1969 Burger 1973 T. pannosus zone C. paradox zone subzone C.h esi subzone D. speciosus subzone oF. wonthazfiensis subzone C. australiensis subzone Fic. 2. Microfossil range chart Fusiformacysta salasit is always rare, but it has a very restricted distribution close to the base of the Cretaceous and early in the C. stylosus spore-pollen zone. Because it occurs in rocks otherwise almost devoid of microplankton, its distribution may be largely facies-controlled. It does seem, however, to occur at a stratigraphically consistent level, within the limits of the spore-pollen zonation. All of the six samples in which it occurs have very low species diversity, but the dinoflagellate frequency with respect to other palynomorphs is variable. The species Fusiformacysta salasti is mor- ROGER MORGAN {| phologically distinct from any cysts described’ from ‘‘ marine’”’ rocks. Acritarchs are rare in, or absent from, these samples. These features of the assemblages are considered by Harris (1973) to be typical of “ non-marine ” Tertiary assemblages. The lithological units with which F. salasii is associated (Lower Hooray sandstone in N.S.W. and Algebuckina Sandstone and lower Cadna-Owie Formation in S.A.) show mostly fluvial lithofacies, with some marine influence in the upper part of the Cadna-Owie Formation. There seems no doubt that F. salasi is a “ non=— marine ’’ dinoflagellate in the sense of Harris. | ! ' microplankton species ocristatum ulatum A o ° a e 1? cee came @ o @ Po. s B el OH ‘cd | ° oa » a n N. monoculatus F. salasii Batiacasphaera macrogranulata occurs at five of its seven localities in association with F. salasii. The lithological units within which it is found (The Upper and Lower Hooray Sandstone in N.S.W., and the Algebuckina Sandstone and Cadna-Owie Formation in S.A.) show a gradation upwards from non-marine fluvial to trans- gressional _lithofacies. The palynomorph assemblages in which it occurs have low species diversity, which increases in younger assem- blages, and variable dinoflagellate frequency | with respect to other palynomorphs. In the — sense of Harris (1973), these features overlap . | | | | | | | rt) H ci eee ee ney EARLY CRETACEOUS ORGANIC-WALLED MICROPLANKTON ‘ the criteria for ‘‘ non-marine”’ and “ marginal marine”’ assemblages. I consider that JB. macrogranulata is restricted to sediments having little or no marine influence. This species occurs at a number of different palyno- stratigraphic levels according to the spore- pollen zonation, hence, this species is probably more valuable as a facies rather than a bio- stratigraphic indicator. Microfasta evansit occurs in Neocomian— Aptian samples from many basins in Australia, only in samples containing few microplankton. In the Great Australian Basin it occurs only once in the fluvial facies, is very common in the transgressional facies and occurs rarely in some samples in older levels of the overlying marine mudstone of the Wallumbilla Formation in N.S.W., and the Bulldog Shale in S.A. It occurs once with F. salasi1 and twice with B. macrogranulata. The assemblages in which it occurs feature low diversity (usually less than five microplankton species), few microplankton with respect to spores and pollen, presence of acritarchs, and the recurrence of constituent species in marine assemblages higher in the succession. These features are considered by Harris (1973) to be typical of his ‘“ marginal marine ’’ assemblages. Thus I consider frequent M. evansii to be “ marginal marine ’’, although the species can tolerate a range from “ non- marine ”’ fluvial to “‘ marginal marine ”’ environ- ments. Support for this view is provided by other data on the distribution of this species. Evans (1966a—b) recorded the species (as gen. et sp. indet. Form A Eisenack and Cookson, | 1960) from rocks in the Otway, Gippsland and Great Australian Basins, which contain few or no dinoflagellates. Evans (1966) concludes that the environment is “ aquatic’. I have seen specimens in the Carnarvon Basin (recorded by Eisenack and Cookson, 1960) and the Perth Basin of Western Australia, where the species is confined to Neocomian to Aptian rocks con- taining few other microplankton. The species is not recorded from marine palynomorph assemblages of the same age, which are frequently rich in dinoflagellates. Nummus monoculatus occurs consistently in the early and mid C. hughesii spore-pollen zone, sometimes rarely, or to 30% of the micro- plankton, making it a good biostratigraphic indicator. It occurs in assemblages which have moderate microplankton diversity (5-30 species), low, variable microplankton content (4-24%) with respect to other palynomorphs, and more | dinoflagellates than acritarchs, in both numbers and diversity. I consider such assemblages 165 “marine ’’, although the low microplankton content suggests that the sample sites were never far from land. “Marine ’’ assemblages of the same age in Western Australia commonly have very high microplankton content (See Wiseman and Williams, 1974), high microplankton diversity, and many different species. These dissimil- arities between Great Australian Basin marine palynomorph and megafaunal assemblages and those of the same age in Western Australia may be a product of geographic barriers, latitudinal differences, shallowness of the Great Australian Basin or a combination of these factors. Diconodinium davidii is restricted to the upper C. hughesti and lower C. striatus spore-pollen zones. It is very frequent in the topmost part of the C. hughesii zone, and frequently comprises 20-40% of the microplankton. The base-range of this species is considered to be an excellent biostratigraphic datum, while the high frequency of the species in most samples makes it easy to recognize. Near the top of its range, in the C. striatus spore-pollen zone, the species is rare. This species is common in all the sections studied, and occurs in the “‘ marine ”’ rocks. Spinidimum boyd ranges from the upper C. hughes to lower C. paradoxa spore-pollen zones. It occurs rarely in many samples, but is very frequent in all “‘ marine’ samples from the middle and upper C. striatus spore-pollen zone, where it comprises 30-60% of the micro- plankton assemblage. The total range of the species is of little biostratigraphic value because it is so rare towards the extreme ends of its range ; the interval over which the species is very common is of considerable stratigraphic value. Spimidinium styloniferum is not common in the Great Australian Basin, and occurs rarely in ‘‘marine’’ assemblages throughout the C. striatus and C. paradoxa spore pollen zones, and is hence of little biostratigraphic value. It is however more common in samples that contain abundant specimens of S. boydit. Bourkidinium granulatum, although always very rare, is very distinctive, and has been observed only in “‘ marine’ assemblages of the C. striatus and lower part of the C. paradoxa spore-pollen zones. It is tentatively used as a biostratigraphic indicator and is frequently associated with rare specimens of Protoellip- soidinium spinocristatum Davey and Verdier, 1971. The latter is recorded previously only from the early to late Albian of the Paris Basin, France by Davey and Verdier (1971, p. 47). 166 The present observations are thus in accord with Harris (1973) with respect to criteria that can be used for environmental conclusions. The new species described here are useful as biostratigraphic and palaeoenvironmental indicators at least in the Lower Cretaceous of the Great Australian Basin. Acknowledgements This article is published with the permission of the Under Secretary of Mines, N.S.W. and the Director of Mines, South Australia. A large part of the work was carried out as research toward the degree of Ph.D. at the University of Adelaide. Mr. T. A. Darragh and the Council of the National Museum of Victoria, Melbourne, kindly made many important specimens from their collection available for comparative study. For helpful comment and criticism, I am grateful to my supervisor, Dr. B. McGowran of the University of Adelaide, Dr. J. W. Pickett of the N.S.W. Department of Mines and Dr. D. Burger of the Bureau of Mineral Resources. I am especially thankful to Mr. W. K. Harris of the South Australian Department of Mines and Dr. L. E. Stover of Esso Production Research Company, who made many detailed suggestions concerning the manuscript. References ALBERTI, G., 1961. Zur Kenntnis Mesozoischer und alttertiares Dinoflagellaten und Hystrichosphaeri- deen von Nord—und Mitteldeutschland sowie einigen anderen Europaischen Gebieten. Palaeon- tographica A, 116, 1. BrIDEAUX, W. W., 1971. Palynology of the Lower Colorado Group Central Alberta, Canada. I: Introductory Remarks. Geology and Micro- plankton Studies. Palaeontographica B, 135, 53. BurGeEr, D., 1973. Palynological Observations in the Carpentaria Basin, Queensland. Bur. Min. Resour. Bull., 140, 27. BurGEr, D. (in press). Some Early Cretaceous Plant Microfossils from Queensland, Australia. Bur. Min. Resour. Bull., 160. Cookson, I. C., and ErsEnack, A., 1958. Micro- plankton from Australian and New Guinea Upper Mesozoic Sediments. Roy. Soc. Vict., Proc. 70 (1), 19. Cookson, I. C., and Ersenacx, A., 1960. Upper Mesozoic Microplankton from Australia and New Guinea. Palaeontology, 2 (2), 243. Cookson, I. C., and ErsENAcK, 1962a. Some Cretaceous and Tertiary Microfossils from Western Australia. Roy. Soc. Vict., Proc., 75, 269. Cooxson, I. C., and ErsEnack, A., 19626. Additional Microplankton from Australian Cretaceous Sediments. Micropalaeontology, 8, (4), 485. Cooxson, I. C., and E1sEnack, A., 1970. Die Familie der Lecaniellaceae n. fam. Fossile Chlorophyta, Volvocales ? Neues Jahrb. Geol. Paldéontol. Mh., 321. ROGER MORGAN Cooxson, I. C., and ErsENAck, A., 1971. Cretaceous Microplankton from Eyre No. 1 Bore, Core 20, Western Australia. Roy. Soc. Vict., Pyoc., 84, 217, Davey, R. J., 1969. Non-calcareous Microplankton from the Cenomanian of England, Northern Fran and North America. Part I. Bull. Br. M nat. Hist. (Geol.), 17, 103. Davey, R. J., and VERDIER, J. P., 1971. An Investi- gation of Microplankton Assemblages from the Albian of the Paris Basin. Verhandel. Koni Ned. ss tae Wetenschap., Afdel. Natuurk., Sect. 4 26 (2), 1 DaveEY, R. Ic and Wix.iams, G. L., 1966. The Genus Hystvichosphaeridium and its Allies, in Studies on Mesozoic and Cainozoic Dinoflagellates. Bull, Brit. Museum, Geol. Supfl., 3, 53. A DEFLANDRE, G., 1935. Considerations Biologique sur les Microorganisms d’origne _— Planctonique Conserves dans les Silex de la Craie. Bull. Biol. Fy. Belg., 69, 213. DEFLANDRE, G., and Cooxson, I. C., 1955. Fossil Microplankton from Australian late Mesozoic and Tertiary Sediments. Aust. J. mar. freshw, |} Res., 6 (2), 242. f DETTMANN, M. E., 1963. Upper Mesozoic Microfloras from South-eastern Australia. Roy. Soc. Vict., Pyoc., 77,91 Detrmann, M. E., and PLayrorp, G., 1969. Palynology of the Australian Cretaceous: A Review; in Stratigraphy and Palaeontology: Essays in honour of Dorothy Hill, 174, Aust. Natl Univ. Press (Canberra). DownlE, C., and SarJEANT, W. A. S., 1964. Biblio- graphy and Index of Fossil Dinoflagellates and Acritarches. Geol. Soc. Amer. Mem., 94, 1. Druaa, W. S., 1967. Palynology of the Upper Moreno Formation (Late Cretaceous-Paleocene) Escarpado Canyon, California. Palaeontographica B, 120, 1. Druae, W. S., 1970. Some New Genera, Species, and Combinations of Phytoplankton from the Lower | Tertiary of the Gulf Coast, U.S.A. North. Amer. Paleontol. Convention Chicago, Proc. G, 809. ; Druae, W. S., and Loesticn, A. R. Jr., 1967. Some | Eocene and Oligocene Phytoplankton from the Gulf Coast, U.S.A. Tulane Stud. Geol., 5, 181. EIsENACK, A., and Cooxson, I. C., 1960. Microplank- ton from Australian Lower Cretaceous Sediments. Roy. Soc. Vict., Proc., 72 (1), 1. Evans, P. R., 1966a. Contribution to the Palynology of Northern Queensland and Papua. Bur. Min. Resour. Rec : 1966/198 (unpubl.). Evans, P. R., 1966. Mesozoic Palynology of the Otway Basin. Resour. Rec. 1966/69 (unpubl.). Stratigraphic Bur. Min. HARLAND, R., 1973. Dinoflagellate Cysts and Acrit- archs from the Bearpaw Formation (Upper | Campanian) of Southern Alberta, Canada. Palaeontology, 16 (4), 665. ; Harris, W. K., 1973. Tertiary Non-marine Dino- flagellate Cyst Assemblages from Australia. Spec. Publs. geol. Soc. Aust., 4, 3. ManvM, S., 1960. Some Dinoflagellates and Hystricho- sphaerids from the Lower Tertiary of Spitzbergen. Nytt. Mag. Bot., 8, 17. Manu, S., and Cooxson, I. C., 1964. Cretaceciil Microplankton in a Sample from Graham Island, Arctic Canada, Collected during the Second ‘Fram’ Expedition (1898-1902). With notes on Microplankton from the Hassel Formation, Ellef Ringnes Island. Schrifter utgitt av det Norske Videnskaps—Akademi i Oslo I. Mat— Naturv. Klasse, Ny Ser., 17, 1. $ | i LG Ly MORGAN PLATI ny Pa PN WY THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES 171 Dalmanitidae. They would have been much easier to enrol, a point that is emphasized by the relatively small size of the auxiliary scars themselves. FiGuRE 2 palpebral regions of Eophacops musheni in dorsal a, b.—(a) Muscles of the axial and aspect. Left side shows the ventral longitudinal and right side the dorsal longitudinal muscles. (6) Cut away lateral view of a generalized phacopid based on Phacops vana and Eophacops mushent. Symbols as in Figure 1 and as follows. a c= alimentary canal; a@ s=apodemal scar; d g= digestive gland ; d / m=dorsal longitudinal muscle ; e d@ m=external dorsal muscle; h=hypostome ; h t=muscles for raising the hypostome; 0 c= occipital apodeme ; s=proximal segment of the occipital appendage ; s=stomach; s m=muscles for suspension of the stomach ; ¢i 1=first thoracic apodeme ; v b=ventral endoskeletal bar; v / m= ventral longitudinal muscle. It is clear that some of the central scars serve to support the alimentary tract as previously indicated. As can be seen from Figure 2, the stomach is in such a position that without anterior and anterodorsal supporting muscles it could not possibly maintain its position. Such muscles are well known in living arthropods (see for example Hessler, 1964, Figure 12). (3) Though they are not clearly seen on the specimen of EF. mushent, members of the Phaco- pidae are known to have a row of scars along the anterior border furrow. These are well shown in Paciphacops birdsongensis (Delo) (see Campbell, in press, Plate XI, Figure 1c), and in Phacops vana muilleri Stewart (see Eldredge, 1971, Plate XIII, Figure 5). These scars are always small, and are probably related to those discussed under (2) above. On the other hand, they may be for the attachment of the muscles that raised the hypostome. In this connection it should be noted that I have not been able to produce evidence of muscle scars on the cephalic doublure of any of the species studied. There is some evidence that the structures so inter- 172 KeiS. W; preted by Eldredge are similar to the collars around perforations through the exoskeleton, and may be related to sensory structures or to tegumentary ducts. It is probable that the hypostomal muscles were attached to the ventral longitudinal muscles rather than the exoskeleton. (4) The scars of the palpebral region form two clearly defined bands in the palpebral furrow and the furrow on the palpebral rim (see Plate A, Figure 2; and Figure 2). The scars are small and approximately equi-dimensional, but they are very closely packed, those in the palpebral furrow being almost entirely contiguous whereas the spacing of those on the rim furrow are a little less dense. There are also occasional scars scattered over the palpebral regions as a whole. (5) All Phacopids have a furrow below the visual surface of the eye, and in E. musheni this furrow is covered with scars somewhat larger than those described above under (4), particularly in the area below lens files 8-14. Towards the front of the eye they form a continuous band, but towards the rear they form semi-discrete patches. Although this concentration of scars is particularly clear, other smaller ones spill down on to the neigh- boring cheek and join a band of scattered scars (6) that run back in an arc across the facial suture on to the lateral parts of the posterior border. This arc lies adaxially to the inner edge of the doublure. So far as I am aware, none of the scars referred to in points 4-6 have been reported previously. Nothing of the kind was noted by Cisne (1974). Consequently it is necessary to glean new evidence to support a functional interpretation. Analogy with living arthropods suggests three possible interpretations of muscles in such lateral parts of the cephalon—extrinsic limb muscles of the specialized cephalic limb, musculature for the suspension of the cephalic ventral endoskeletal bar(s), dorso-ventral muscles that attach to the ventral membrane and operate to vary the turgor of the body fluids. The X-radiographs of Sttirmer and Bergstr6m show the presence of large proximal segments on at least the two posterior cephalic appendages, suggesting that these limbs had a specialized role in food-gathering. (Similar results have been obtained for Tviarthrus by Cisne (1974, 1975), and for Olenus by Whitting- ton (1975)). Such structures would presumably require specialized musculature additional to that inserted into the glabellar furrows in order to produce rotation. The length of the area of insertion along the palpebral region in species CAMPBELL with large eyes, is sufficiently great to produce rotation in both clockwise and anticlockwi directions on the three posterior cepha appendages. In Limulus, a primitive arthropod with complex limbs in the region of the mout the extrinsic muscles extend laterally well beyond the line of the apodemes into the region of the eye (Benham, 1885, Plate 76, Figure 1). During enrolment of a phacopid there would be Eophacops mushent. The sections are across t posterior and anterior parts of the eyes respectively i a tendency for the ventral longitudinal muscle x to pull the endoskeletal bar downwards (seej) ” Figure 2b), and hence it would be mechanically a advantageous to have dorso-lateral support from in the palpebral region. Evidence favouring this ie view again comes from Limulus which has the is ventral endoskeletal bar supported laterally byil) a pair of muscles (Benham, 1885, muscles 58!\) ™ and 59). Incidentally I see no need to postulate ul the presence of more than one endoskeletal bar pi in the cephalon of phacopids as Cisne has done ! for Triarthrus. a | ry pi im pe hi ye w it L th th it - eT a ee ike Lh a | ot { heal if ieee ; i) t Sea ‘ fae i> os ab [=F SSS Ms 4 il FicuRE 3 a, b.—Cross sections of the cephalon of 2 i generalized phacopid based on Phacops vana an a | The form of the digestive glands is hypothetical Symbols as in previous figures and as follows. ant antenna ; d v m=dorso-ventral muscles : o=oesophagus. ‘ iy Fortunately there is further evidence from the }}j “ Hunsriick phacopids bearing on this problem. }} The so-called ommatidia of Stiirmer andi} " Bergstrém discussed below in the section on jj * eyes, could reasonably be interpreted as py ed i tendon or muscle tissue. Cisne (1974) he t shown that pyritization of this type can occ and Bergstrém (pers. comm.) reports that a | e | i va : og THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES has seen it also in specimens of Mimetaster and Cheloniellon from the Hunsrtickschiefer. The fact that in the phacopid material the striation in question is so intimately related to the eyes is consistent with the scars of the palpebral regions of E. mushent. In addition, one of the specimens of Stiirmer and Bergstrém (WS613, Plate 18) shows a diffuse mass of tissue extending in a backwardly curved arc across the cephalon from eye to eye. This would correspond well with the predicted position of a support for a ventral endoskeletal bar. Moreover, in living forms the bar is sometimes supported by dorso- lateral and ventro-lateral muscles (see Hessler, 1964, Figs 11, 25, 28 for Tviops and Hutchin- soniella, and Benham, 1885, for Limulus), and consequently it is within the bounds of uniformitarian argument to interpret the phacopid scars in this way. On the other hand, the disposition of the scars on the lateral and posterior cephalic borders is not consistent with this interpretation, as the cross-section in Figure 3 shows. It is possible that these are the scars of dorso-ventral muscles that functioned in the same way as the pleural muscles discussed under (6) below. This opens the possibility that other dorso- ventral muscles were attached to some of the scars in the palpebral region, particularly those on the palpebral rim. However the scars on the subocular furrow are so strong, and so closely clustered that they may be better interpreted as supporting the ventral endo- skeletal bar. (6) Along the interpleural furrows of the pygidium there is a concentration of equidimen- sional scars that extend laterally to the line of the inner edge of the doublure where they stop abruptly. Some scars also occur on _ the posterior and/or anterior pleural bands. These scars are not so closely packed as those on the palpebral lobes. On the posterior half of the pygidium the scars of the various segments begin to mingle. There are a few scattered scars posterior to the axis. Comparable scars on the thorax are difficult to observe, but there appear to be some on the posterior pleural bands lateral to the fulcral points and there may be a few more on the anterior bands medial to the fulcral points. By analogy with living arthropods there are two possible functions for these muscles—lateral suspension of the ventral endoskeletal bars, or suspension of the ventral membranes. As has been shown above, strong ventral musculature must have existed in the phacopids, but it is probable that these muscles were attached 173 directly to the dorsal exoskeleton in the axial furrows. Thus there would not have been any ventral endoskeletal bars in the pygidium. On the other hand, the wide spread of these scars and their termination along the line of the doublure are consistent with the alternative view that they were for the dorso-ventral musculature. Ficure 4 a, b.—Reconstructed sections through a lens of P. vana milleri showing the various lens elements and lamination. ¢ c=central core; c¢ m=corneal membrane ; 7 / b=intralensar bowl ; 4 l=inner layer; o /=outer layer; s c=sclera. (7) The presence of external dorsal muscles has been postulated by Hupé (1953) on the grounds of their presence in living arthropods, and the obvious maximal flexing efficiency of muscles inserted in that position, but it has been difficult to demonstrate their existence. Opik (1937) recorded the presence of paired 174 scars in the pygidium of Reraspis plautini which he regarded as the insertion sites of extensors, but their paired nature suggests that they are likely to be extrinsic hmb muscle scars. Whit- tington and Campbell (1967) described non- silicification of the anterior edges of the half- rings in species of Proetus, and this may represent a variation in composition of skeletal tissue where the external dorsal muscles as well as arthrodial membranes were inserted. E. mushent shows arcuate scars in the anterior edges of the pygidial pseudo-half rings, which structures are common to all members of the Phacopacea and many other trilobites. In addition the leading edges of the half-rings on the thorax show dark discoloration of the same type, indicating that similar soft tissues were attached there also. I take this as very strong support for the existence of external dorsal muscles. THE EYES Introduction The compound eyes of the Phacopacea have excited interest for almost 140 years (Quenstedt, 1837) and recently they have been subjected to considerable analytical treatment especially by Clarkson (see Clarkson, 1975, for summary and biblography). In particular, the visual fields have been inferred from external morphology found in members of the group; thin and polished sections have provided data on lens structure and on the possible positions of the light receptors, and a certain amount of specu- lation on the physiology of the eye has ensued. By and large it has been concluded that the Phacopacea had ommatidial eyes of the apposition type ; that the fields of view of the whole eyes usually cover horizontal arcs of 120° to 170° (though the angle is reduced to a few tens of degrees in some late genera such as Cryphops), and vertical angles of 20° to 40°; that the internal structure of the lenses varies from genus to genus and may be indicative of systematic relationship ; and that the eyes may be sexually dimorphic. The main contentions of this lecture are that the eye structure has more in common with reduplicated ocelli than with compound eyes ; that although the internal structures of the lenses vary from species to species, there is nevertheless a basic pattern common to all, and that this pattern is necessary because of the highly birefringent nature of the calcite of which they are composed ; and that the eyes are definitely sexually dimorphic. K. S. W. CAMPBELL iT Internal Structure of Lenses The internal structures of the lenses of Paciphacops logami, Paciphacops birdsongensis, Phacops rvana, Eophacops mushent and Reedops deckert have been examined in polished section | and by immersion in high refractive index | liquids. P. birdsongensis has also been examined — in partially silicified material, and specimens of R. deckert in which some of the intralensar | structures are replaced by a ferruginous | substance that outlines the structure with great | clarity, have also been available. Finally, thin” J sections of P. vana have been prepared for observation in polarized light. ao cea Zz; eS SO = eS In all these types of preservation the following elements have been observed : (a) an outer layer or corneal membrane ; (b) an upper unit ; (c) a central body or core, termed the proximal nucleus by Clarkson (1969) and the subcorneal — lens by Towe (1973) ; (d) an intralensar bowl ; and (e) a basal layer. The fact that they are present in such different modes of preservation indicates that they are original structures and are not the result of diagenetic changes. In | summary the lens elements are as follows. (1) An outermost layer, referred to by Clark- son (1967) as the corneal membrane, covers the whole external surface of the lens and penetrates | i the interlensar sclera. In some specimens of P. vana the detail of this layer is visible and uf is seen to be composite. The most prominent feature is a dark layer which is partially or completely covered by a clear layer, and pene-— trates the entire depth of the sclera. This dark layer is seen at high magnifications to consist of a number of laminae. The overlying clear layer joins the sclera around its margins. Forming a— continuous film across the lens surface beneath — the dark layer is another clear layer which is usually thinnest axially and thickens to two or three times its axial value peripherally. This thickening in some specimens is achieved by a series of ragged interdigitations with the “ upper unit ’ of the lens which is described below. This_ clear layer is apparently continuous with a thin basal layer of similar appearance around the base of the entire lens. The orientation of the carbonate in all these layers is not completely clear because the thickness of the sections makes interference between the adjacent layers so great that it is difficult to make unambiguous observations. However, I suspect that the | microcrystalline carbonate forming them has | random crystallographic orientation. ; (2) An upper unit of variable thickness _ t consisting of calcite with its C-axes oriented as i| * | | ) _~ er en a ee a Soe te he . ere THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES shown on Figure 6. This unit shows distinct lamination with the laminae having a lesser curvature than the lens surface. Notice that the orientation of the C-axes changes in a regular manner so that over most of the upper unit they remain at 80°-90° to the surface of the lamina in which they occur. The laminae may be formed of organic material. Though B Ficure 5 a, b.—Diagrammatic sections of the lenses of the two morphs of Paciphacops raymondi (Delo) from the Haragan Formation, Oklahoma. Drawn from polished surfaces. Further details in Campbell (in press). it has not been possible to confirm this by direct determination, the presence of organic material in other parts of trilobite exoskeletons as well as other calcified arthropods (Dalingwater, 1973) supports this hypothesis. Further, the cloudy appearance of the lenses in thin section is caused by patches of dark material, more or less irregularly distributed but showing some banding. These patches have not been intro- duced into the lenses after death, but probably result from decomposition of the organic layers. Variation in the refractive index within the corneal lenses of living arthropods by chemical variation of the layers, is a well-known phenomenon, though this is probably not their function in phacopid eyes. 175 (3) An ellipsoidal to pyriform central core that varies in size and position, is enveloped in a layer that is formed of unusually clear calcite. In some species it is in contact with the basal layer of the lens, and in others it is well above the basal layer (see Figure 5). The central part of the core has a dirty appearance due to inclusions. Overall, the calcite of the core (including its envelope) is oriented with its C-axis parallel with the lens axis. In species from the Early Devonian Haragan Formation the envelope and the corneal membrane are preferentially replaced by iron compounds. (4) The intralensar bowl is formed of calcite with many inclusions. It is sometimes preferentially dissolved during diagenesis. Its calcite is in optical continuity with that of the central core. This unit and the central core are both crossed by laminae similar to those described for the upper unit. (5) The basal layer can usually be traced around the lens into the lower layers of the corneal membrane. This is also apparently composed of clear, randomly oriented, micro- crystalline calcite. It was suspected that the different lens components would vary their refractive indices by substituting various elements in the calcite lattice. The three possible substituting elements are Fe, Mn and Mg. Microprobe scanning failed to show traces of the first two, and the variation in Mg is so small that it would have no effect on the refractive index (Figure 6). Sub-lensar Structures Clarkson (19675) in his discussion of the physiology of Phacops eyes assumed that ommatidia existed, and that given the orientation of the lens axes and the sublensar alveoli, such ommatidia would have been short and of apposition type. More recent work by Stiirmer and Bergstrém (1973) on pyritized specimens from the Hunsriickschiefer, has suggested that there were extremely long ommatidia extending from the eyes to some indefinite area beneath the glabella. Clarkson (1973) has already given reasons for not accepting this interpretation, and with these I am in agreement. Dr Bergstrém has generously lent me the relevant radiographs and the following features of the structures in question are apparent in them. (a) They are not disposed along the optic axes of the lenses. This is not simply to be explained as a result of post-mortem deformation because they could never have been along the lens axes without crossing one 176 another, and yet in most specimens they have a more or less regular radial pattern. Moreover, the optic axes of the upper rows of lenses of many phacopids intersect the axial furrow and hence the ommatidia could not have passed FiIGuRE 6 a, b.—Diagrammatic sections of lenses of P. vana milleri. (a) Distribution of magnesium expressed as weight percent MgO in a lens. Measurements transferred from the analyzed lens to the generalized model. (b) A lens showing the orientation of the c-axes of the calcite on the Tight side of the upper unit. The dotted line passes continuously along c-axes. On the left is the extinction area when the analyzer is 10° to the left of the optic axis. beneath the glabella. (b) They appear to form a planar set and not a block of rays as they should if they were developed behind all lenses. This can scarcely be explained by pyritization of the surface set of ommatidia only, because of the similarity between specimens and the fact that considerable thicknesses of other tissues are K..S.' W. CAMPBELL pyritized. (c) As Clarkson has pointed out, | the rays extend beyond the palpebral region in some specimens. Bergstrém (pers. comm.) | now believes that the rays may be exite filaments © from some of the cephalic appendages, and there is little doubt that such structures are visible on some specimens. Clarkson hag suggested that they may be parts of a caecal system. In my view, some of them may be interpreted as tendons or muscle fibre bundles (see above). But there is now little support for | the view that they are ommatidia. The only other observed sublensar structures ; that may have a bearing on this problem are those figured by Clarkson (19676, Text-Fig. 1 1969, Text-Fig. 2, 3). These are rare thin= walled cylindrical structures with their walls apparently continuous with the inner edges of | the corneal membrane embedded in the sclera. — The cylinders are approximately 2-5 times the height of the lens surmounting them. Clarkson (p. 606-607) regarded these structures as the equivalents of the crystalline cones found below the corneal lenses of most modern ommatidial eyes, though he did countenance the possibility that they were the membranes in which thi ‘ photoreceptive organs ’ were contained. Another feature that has a bearing on this” problem is the fact that (Clarkson, 19676) i some parts of the eye the cylinder of sclera has | its axis at an angle to the optic axis of the len situated within it. This is a peculiar arrang ment if there were long ommatidia behind thi lenses, as the ommatidial axes would be expected to be coincident with both the optic axes of the | lenses and the axes of the scleral cylinders. i Thus the observed structures do not lead one to infer ommatidia or any other kind of sublens structure that can be directly related to modern arthropods. The interpretation of this region of the eye is dependent on indirect evidence, some of which will now be considered. : . Indirect Evidence Bearing on the Nature of | the Visual Units ; Apposition compound eyes are the most. common type of eye in living arthropods. They occur in a wide variety of diurnal forms rom fast flying insects to slow-moving benthic marine crustaceans, and in different parts of this wide range they exhibit some distinctive structural adaptations. Consequently a discussion on the | relevance of modern forms to the interpretation | of phacopid eyes should concentrate on slow- moving aquatic animals. y| It is known that the effectiveness of moderiitl compound and ocellar eyes depends on a number | on ed a a ee ee ed Se ee THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES of factors including the diameter of the lenses, the capacity of the lens to produce a good focus, the size of the receptors with respect to the size of the Airy disc associated with the focus, and the position of the receptor surface with respect to the focal plane of the lens. In addition, apposition eyes require small interommatidial angles and this, coupled with the multiplicity of their lenses, permits them to have much smaller lenses than ocellar eyes without loss of ‘sensitivity. Assuming that phacopid eyes obeyed similar principles, it should be possible to determine if they approximate more closely to ommatidial or ocellar eyes. The high double refraction of calcite makes it an unlikely substance to use in a lens system. Apposition eyes depend on focusing a beam of light on the end of a small rhabdom, the crystalline cone usually acting merely as a spacing element, thus making the best use of the acuity conferred by the lens. The lens of a phacopid is a very complex structure, and although attempts have been made to show that a beam parallel with the optical axis would be focused at an appropriate point (Clarkson and Levi-Setti, 1975), no discussion of the behaviour of an oblique beam has been attempted. More- over, these authors suggest that the ordinary and extraordinary rays would focus in different planes. There is the additional problem that their lens model may be incorrect (see below). Hence there is as yet no evidence from the dioptric system for or against the apposition hypothesis. The diameter of the corneal lenses in apposition eyes of slow-moving aquatic arthro- pods is rarely greater than 0-2 mm. For example, in specimens of Limulus with eyes approx 10 mm long the largest lenses are only 0-2 mm in diameter, and this only in animals that are many times the size of a phacopid. Although Limulus and Phacops eyes are com- parable in shape, it is not uncommon for the lenses in a Phacops eye about 10 mm long to be up to 0-7 mm in diameter (Clarkson, 19665), and eyes only 4:5 mm long frequently have lenses up to 0-4 mm. Consequently phacopid lenses are three times greater in diameter than the largest of those in ommatidial eyes, and they are an order of magnitude larger than most. It may be argued that the large diameter of phacopid lenses increased sensitivity, and that this was necessary because the animals were adapted to dark conditions or to nocturnal habits. The former proposition may be ignored because the geological evidence is that most of them lived in clear shallow water, but the latter 177 FIGURE 7 a-c.—-Reconstruction of an ocellus of the larva of the sawfly Perga based on the work of Meyer-Rochow (1974). (b, c) Reconstruction of an ocellar eye of the larva of the ant-lion Ewyvoleon modified from the work of Jockusch (1967). C=cuticle ; C M=corneagenous material ; R=rhabdoms ; Rm=rhabdomeres. proposition may well be true. However, I can find no examples of living species in which the lens diameter is unusually large either because of the generally dark conditions or nocturnal habits (see for example Doflein, 1904; Welsh 178 and Chace, 1937). The deep sea Brachyura described by Doflein (1904) have corneal facets 35-100 pw in diameter, and there seems to be no systematic variation of lens size with total eye size. These values are no different from those of Brachyura from shallow water environments. Consequently the large lens diameters are not likely to be explained in terms of operation under dark conditions. For an eye of given size and curvature, and lenses approximately in contact with one another laterally, increase in lens diameter automatically increases the interommatidial angles. Increase in curvature of the eye surface without increase in size also increases the interommatidial angles. In most omma- tidial eyes, even in slow moving crustaceans, these angles are usually 4-8°. In Limulus, Waterman (1954) records interommatidial values between 4—15°, the high values being confined to the region of high curvature at the posterior of the eye. Over the area of greatest lens concentration in the eye of Phacops rana millert “ the longitudinal axial (interommatidial) angles average 6°, but they increase anteriorly to 14°, and posteriorly where the curvature is extreme, to 20°. Latitudinal axial angles are about 3° in the region of maximum _ concentration, increasing upwards to 14° ; in other parts of the visual field they average 10° (Clarkson, 1966), p. 470). Other phacopids have somewhat smaller angles, but still large in comparison even with Limulus. In almost all phacopids the sclera between the lenses is thick, and in P. vana it is especially so. As a result the interommatidial angles could be considerably reduced while maintaining the lens size, simply by closer packing. In this respect, therefore, if the eyes are ommatidial, they do not make optimum use of the space they occupy. Evolutionary trends in phacopids are towards reduction in the number of units in the eye, whereas in ommatidial compound eyes the trend towards better eyes invariably has involved an increase in the number of facets and reduction in the interommatidial angles. It is difficult to conceive of phacopid eyes with two or three lenses being ommatidial. Finally, nothing is known about rhabdom size in phacopids, and this factor cannot be used in the present argument. Consequently, on balance, the indirect evidence suggests that the characters of the optic units in phacopid eyes are not those associated with ommatidia. On the contrary, if ommatidia lay behind the facets it would seem to be impossible for even the best of them K. S. W. CAMPBELL to resolve objects subtending small angles at the eye. An Alternative Hypothesis If the eyes are not ommatidial the only alternative by analogy with living forms is that — they are ocellar. Of course, they may be of a type which has no modern analogue, a view which is lent some credence by the fact that the lenses are composed of calcite, a substance not used in living arthropod eyes. Lindstr6m (1901, p. 31-34) considered that the trilobites Harpes, Harpides and possibly Trinucleus had 1-3 ocelli, but phacopid eyes were not considered to be of this type. He referred to them as “ aggregate eyes’, a special category. In living arthropods compound ocelli are not common, and where they occur they are usually in aggregates of up to six units. They are most common in the larval stages, though a group of three ocelli is common in many adult insects. The arrangement of the units is not always in a regular geometrical pattern. However, even in larvae the lenses reach a diameter of 0-35 mm, which is many times larger than the largest ommatidial lenses, but comparable with those of phacopids. The | structure of the lenses varies from group to | group, but in essence they are formed of several layers with differing refractive index contained | within a corneal and a basal membrane. The — lens of the sawfly Perga is in many respects like | the lens of a phacopid (Meyer-Rochow, 1974, Fig. 13). It is strongly biconvex and consists of a basal unit like the intralensar bowl, and an upper unit which is apparently homogeneous. The differences between this and a phacopid are © probably the result of the use of calcite in the phacopid lens. The sublensar structures in ocelli also vary considerably, but basically they consist of transparent corneagenous tissue immediately below the lens, and below that a layer of retinula cells the upper surface of which lies approxi- mately at the focal plane of the lens. The transparent tissue and the retinula layer are | encompassed by a pigmented layer (see Jockusch, 1967, Fig.3 ; Meyer-Rochow, 1974, Figs 4, 14, 15). One interesting feature of these structures in the antlion Euroleon nostras figured by Jockusch, is that in relative depth they are comparable with the sublensar cones described by Clarkson for Phacops fecundus and Reedops cephalotes. This suggests the possibility that there was trans- parent tissue occupying the space within the scleral lumen, and the distal edges of the retinula cells formed a surface as shown in eee ee SS ee ee ee THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES It is interesting that the larva of Figure 8. Euroleon with six ocelli in its array has fewer retinula cells per ocellus than Perga, which has only one ocellus. Presumably this simply means that each ocellus in a multi-element eye is required to scan a smaller part of the field, and one would therefore expect Phacops with its multitude of lenses to resemble Euroleon, as it would if the reconstruction in Figure 8 is correct. Such an arrangement offers an explanation of the divergence between the axis of the scleral cylinder and the optic axis of the lens—they would not need to be coincident if the retinula cells were close to the base of the lens. (A further advantage of this pattern is discussed below.) Also, since these sublensar units are so short they would in no way obstruct the muscle bundles attached to the ventral surface of the palpebral furrow and the palpebral rim. For such an interpretation to be valid, however, it would be necessary to show that the focal plane of the lens at each locus is approximately in the position predicted. The only way of approaching this problem is by ray-tracing. This can be done with some accuracy for Phacops rana using the lens model outlined above and making certain minimal assumptions about the refractive indices of the various lens layers and the proposed cornea- genous layer. Using a lens model based upon the features - described above, my two colleagues R. A. Eggleton and L. Belbin have computed ray paths for P. vana. Some simplifications of the model have been used but these are not regarded as significantly affecting the dioptrics. Thin layers of organic material with a refractive index of 1-50 have been placed in the upper unit. They have almost no effect on the ray path. It is considered possible that their function from an optical point of view was to separate the layers of calcite so that the orientation of the c-axes in successive layers could change in the manner shown in Figure 6. From a morphological point of view they represent growth layers. Similar layers occurred in the intralensar bowl and the central core, where the c-axis has a constant direction, but they would not have had any effect on the ray path unless they occurred in great numbers. There is no adequate evidence for this, and so they have been ommitted from the model. A _ second simplification is that the c-axes in the upper unit are considered to be normal to the surfaces of the layer in which they are found whereas they are apparently at 75-90° to the surfaces. The refractive indices of sea water and the 179 sublensar organic material have been taken as 1-33 and 1:35 respectively. Since the lens has been determined to be almost pure CaCQg, calcite refractive indices have been used appropriately for ordinary and extraordinary rays. 1004 FIGURE struction of an optical unit of a 8.—Diagrammatic recon- phacopid trilobite. (Same symbols as Figure 7.) For the ordinary rays from a parallel beam of light parallel with the optic axis, the focal length of the lens is approximately 1-6 times, and for the extraordinary rays approximately 1:65 times, the lens thickness. Given the imperfections of the model and the approxim- ations involved, these foci are sufficiently close to be considered as coincident. Similar beams incident at 10° and 20° to the optic axis also produce approximately coincident foci for the two rays, though the definition of the foci is rather poorer than that of the rays parallel with the axis. All rays focus approximately in the same plane (see Figure 9). It is concluded from these data that the lens model is reasonably accurate. In particular, the coincidence of the ordinary and extra- ordinary rays is regarded as remarkable, and an improvement over the model used by Clarkson and Levi-Setti. To check that the crystallographic orientations used are really significant, other models with different orientations were also tested, but they either did not produce a focus or there was a poor focus at a remote focal plane. K. S. W. CAMPBELL 180 =e ne M7] 7 eet rs \\ e Ficure 9.—Computer simulated ray paths through the lens model used in Figure 6. Transverse lines in the upper unit represent laminations. Some paths are obviously displaced, probably because of the method of digitizing the lens elements in 5° units. The four pairs of figures show the ordinary and extraordinary rays incident respectively at angles of 0°, 10°, 20° and 30° to the optic axis of the lens. 181 182 It may be reasonably be assumed that the focal plane of the lens defines the upper surface of the retinula layer. That this is not concave is a matter for some surprise because the trhabdoms would be expected to be oriented approximately parallel with the lght beam. However this may be the result of slight errors in the model and in the calculation of the ray paths. The depths of the sublensar capsules in the species where Clarkson has observed it are approximately the same relative to the size of the lenses—v7z 1-5—2-0 times the lens thickness. This indicates that the scleral lumen and most of the sublensar capsule would have been occupied by the transparent corneagenous layer. It seems probable to me that short rhabdoms occupied the bottom of the capsule, the basal membrane of which was the basal layer of the visual unit in the same manner as in Euroleon. However, the possibility that the rhabdoms lay beneath the basal membrane of the capsule cannot be disregarded. As can be seen from Figure 9, light incident at angles greater than about 22° will impinge on the walls of the sublensar capsule or the sclera before reaching a focus. This gives the lens a relatively narrow field of vision in comparison with the ocellar lens of Perga, but it is quite consistent with the interocellar angles referred to above. Although the total angle of vision of each lens is 45—50°, the focus is good only in a relatively small foveal region. The amount of light reaching a laterally placed rhabdom will depend on the angle of incidence of the light, but it might be expected that as little as 30% of the incident light in a beam will focus on any given rhabdom. Thus although the data are not good enough to produce precise figures, it would be surprising if high acuity and high sensitivity occurred outside a small group of centrally situated rhabdoms, and _ this effectively restricts acute vision to directions within a few degrees (10° at the most) of the optic axis. Under these circumstances the overlap of acute vision between neighbouring visual units will be small. It should be noted that in the ommatidial eye of Limulus, although the total visual angle is approximately 50° the acceptance angle (ie. the angle of 50% sensitivity) is only +6° (Kirschfeld and Reichardt, 1964, p. 49), and in Limulus the interommatidial angles are not greatly different from the interocellar angles in P. rana. According to the above authors the large overlap of the visual fields of adjacent ommatidia in Limulus is effectively reduced by a lateral K. S$. W. CAMPBELL even at the margins of the retinula suggests a reason for the asymmetry of the scleral lumen — Figure 10 a, b.—(a) Horizontal and (b) vertical sections through the eye of Reedops sternbergi, redrawn and modified from Clark- son (1969). Note the asymmetry of the sclera with respect to the optic axes (dotted lines). Sublensar structures inferred from membranes figured by Clarkson, and rhabdoms (r) hypothetical. Solid lines through lenses give an indication of the disposition of the visual field around the optic axis. with respect to the optic axis of the lens, in the visual units near the periphery of the eye. This effect was noted by Clarkson (1967 ; 1969). As is shown in the horizontal section in Figure 10a, the asymmetry has the effect of increasing the Sos ee Ss eas ase Se Se Se Se Fs SS SSS tay ! U “Tiwell covered by many ie is , Ie | | THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES field of vision of the eye at the anterior and posterior ends, though the quality of the images at the limits of the field would have been relatively poor. Also as noted by Clarkson, }| vertical sections of the eyes of most species show the sclera disposed horizontally, and the sclera bounding the upper edge of the lens projecting further inwards than that bounding the lower edge. This results in a far greater asymmetry than that in the horizontal sections, and is best illustrated by sections of Reedops sternbergi given by Clarkson (1969, Text-Fig. 4). Such an arrangement is possible only because the vertical inter-axial (interommatidial) angles are much smaller than the corresponding horizontal ones, and hence the vertical field is lenses. It is not surprising, therefore, to find that the higher lenses in each file are positioned in the sclera so that the effective field of vision is greater above the horizontal than below it (see Figure 100). The Functioning of a Phacopid Eye Thus a case can be made for considering that each lens in a phacopid eye was at the apex of an ocellus-like structure. No living organism, however, has anything comparable with the total eye complexity shown by phacopids, and so it is now necessary to try to determine what advantage this complexity confers. To do this it is necessary to examine the function of known ocellar eyes. Pure ocellar (or stemmatal) vision is found in living arthropods among slow-moving terrestrial or aquatic adults, or in the larval stages of forms which change to ommatidial vision in the quick- moving adults. What advantage is it then for a slow moving organism to have ocellar vision ? Meyer-Rochow (1974, p. 1588) has shown that the “little stemmata of sawflies are capable of polarization sensitivity, motion detection and form and colour perception ’’, and this achieved | with a single lens on each side of the head. | Moreover, because of the design of the lens, the | a total visual field is about 200° with a 50% value of 140°. On the other hand acceptance angles of individual centrally situated rhabdoms | have been determined by ray tracing methods | to be as low as 3-6° whereas those towards the periphery are up to 16-4°._ Experimental work gives somewhat larger values. Mean acceptance angles for all rhabdoms are approximately | 11-5+5-1° in the light adapted and 13-8-++6-8° in the dark adapted state. The mean apertural angle is 40°+. High resolution is restricted to | the axial part of the receptor system, the | resolution values falling off rapidly towards the «@ a 183 limits of the retinula. Nevertheless angles as low as 4° can be resolved. Forms with compound ocelli such as the larvae of tiger-beetles, ant-lions, cabbage caterpillars and the like, with up to six lenses in each array, have also been studied in detail. Jockusch (1967) has described the most regular of these, the small domed eyes of the antlion larva (Euroleon nostras). A diagrammatic section is shown in Figure 7b. The individual units are separated by thick pigmented bands which are continued around the bases of each group of rhabdoms. Mean acceptance angles for all thabdoms are approximately 16° but the total apertural angle is approximately 47°, a value much less than that given above for Perga. The angle between the optic axes of adjacent ocelli is approximately 60°, and this together with the apertural angle above gives each aggregate eye a cone shaped field with an apical angle of approximately 170°. However, because of the high interocellar angle not all points within this cone are efficiently scanned while the eye is stationary, so that some movement of the animal is required to cover the field with acute vision. Without behavioural studies it is not possible to determine the capacity of these eyes for movement and form perception, and no measurements of their acuity are available. However, assuming that each ocellus had comparable acuity to those of Perga, it would seem that the increase in number of ocelli increases the acuity of the eye over the whole field but it does not expand the size of the field. In other organisms the ocelli are not arranged in geometrical fashion but are spread more or less randomly along each side of the head. Details of the fields and acuities of these eyes have not been available to me. If the conclusion that the phacopid visual units are ocellus-like is correct, there is no known living form with the ocelli arranged in a comparable geometrical pattern. What then is the significance of the phacopid pattern ? Clarkson has proposed that it is an adaptation to movement perception. Longitudinal move- ment was detected only because the visual field is divided into vertical strips which are the result of organization of the lenses into vertical files, and latitudinal movement perception is possible because the slight vertical curvature of the visual surface produces continuously changing elevations in the successive lens axes in each vertical file. This interpretation is almost certainly correct as far as it goes, but it leaves two points without satisfying explanations. 184 (a) The Phacopina with schizochroal eyes is related to the Cheirurina with holochroal eyes (Moore, 1959), and probably developed from it. Holochroal eyes have lenses without intervening sclera and their facet diameters and “ interom- matidial angles ’’ are comparable with those of apposition eyes of living arthropods. These are known to function well as movement detectors, their efficiency being attested by the fact that they are found in a large number of distantly related groups. Is it reasonable to suppose, therefore, that schizochroal eyes conferred some special advantage for movement detection rather than a capacity of some other kind ? (b) Some schizochroal eyes have only a few lenses and these are often irregularly arranged so that they cannot have functioned in the manner indicated for multi-element forms. Eye reduction occurred independently several times in the Phacopina between the Late Silurian and the Late Devonian. Examples are Denkmannites (Late Silurian), Prokops (Early Devonian), Reedrops (Early-Middle Devonian), and Cryhops (Late Devonian). It is often suggested that eyes of this type were degenerate and that animals bearing them lived in the deeper and darker parts of the sea (see Clarkson 1967a for summary). This interpretation is faced with some real difficulties. Forms with reduced eyes are found in shallow water deposits with large-eyed species in_ circumstances indicating that they have not been transported (Chlupaé, 1966, p. 126). The lenses in species with reduced eyes are invariably directed anterolaterally, the direction covered by the densest lens array in multi-facetted species, and hence the direction of most acute vision. This suggests that reduced eyes were still functional. The little evidence available (there has been no detailed work yet) on lens structure suggests that lenses in reduced eyes are comparable with those in large eyes. Nor can the irregularity of the arrangement of the small number of lenses be regarded as indicative of degeneracy, for groups of ocelli are often irregular in modern organisms (e.g. the larvae of tiger beetles, Friedericks, 1931) while being highly functional. Of course the rhabdoms and nerves could have been degenerate, but that cannot be checked, and such a view should not be invoked without strong support from some other source. We are left, therefore, with functional reduced eyes that could not have formed visual strips or measured elevations by engaging successive lenses in a vertical file. The ocellar hypothesis provides the possibility of another explanation. The very similar K. S. W. CAMPBELL | . biochemical and neurophysiological properties of © ocelli and compound eyes, and the fact that | they occur at different ontogenetic stages of th i same organisms suggests that they are under the control of the same genes. It is interesting |} i! to note therefore that although the trilobite family Cheiruridae is predominantly holochroal some of its members, e.g. Holia and Acanthe parypha, have multi-element eyes with larger lenses than normal and some features in common | with schizochroal eyes (Whittington and Evitt, | 1954). It may be that this is an example of an abrupt change in gross eye morphology resulting from a small genetic change. As indicated | above the Phacopina may have been derived © from the Cheirurina, and schizochroal eyes m have resulted from a similar change. If this is the reason for the large number of lenses, it is then possible to offer a reasonabl . explanation for eye reduction. Essentially thi depends on the fact that the field of vision and the range over which the vision is acute can extended by increasing the number of rhabdoms behind each lens and improving their response. | Each optic unit in a large eye would have a | number of rhabdoms, and the amount information received would have been enormou requiring a very complex nervous system. | Consequently, it would be expected that in eyes with a large number of lenses, each visual unit | would have had relatively few rhabdoms, acute vision being restricted to a small number of them near the centre of the retinula. Eyes with only a few visual units would be expected to ~ have more rhabdoms distributed over a surface of slightly greater diameter, and lens and | sublensar designs that would permit the expansion of the visual field. In addition the | size of the “ focal fovea ’’ over which there was high resolution would be expected to be larger. | We are still left with the problem of complete | blindness. It is not the result of life in the | deep sea. Erben (1958) has suggested that | accidental eye reduction took place in well- | lighted environments and animals bearing reduced eyes were preadapted to live in dark or semi-dark environments, and hence were more . successful than forms with normal eyes. This explanation may be thought to account for the | occurrence of reduced eyes with normal ones in — shallow-water deposits. However, it really is no explanation at all—it depends on an | unexplained accident. If, on the other hand, eye reduction is adaptive, as suggested above, ' it may be possible to explain not only the repetition of reduction in the family, but also | the repetition of blindness. The general habit | ao eS a a ee THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES of phacopids with large eyes may be inferred with confidence from the studies of the sensory and limb structures in such species as those described by Stiirmer and Bergstrém (1973) and Miller (1975). They must have been active epifaunal carnivorous animals. Nothing is known of the limbs of blind phacopids but a good deal is known of their gross morphology. Many have depressed exoskeletons with acutely angled profiles on the front of the glabella, and the entire dorsal surface is without macro-ornament. in rhabdom size. Most of these types are preserved in muddy sediments. All these features are consistent with a shallow burrowing mode of life, whether it be burrowing in mud or in a dense mat of weed on the bottom. Note that although some genera with reduced eyes have a similar gross morphology (e.g. Denkmannites which includes both sighted and blind species (Schrank, 1973)), there are others that are little different from contemporaneous species with normal eyes. Eocryphops, for example, is highly ornamented and similar to contemporaneous species of Phacops. GG Ficure 11.—Suggested evolution of some trilobite eye types. holochroal type with gradual reduction in lens size, increase in lens numbers and increase in eye size. D, the abortive development of the Acanthropharya eye type. gradual reduction in lens numbers and increase in the number of rhabdoms per lens, and decrease H, one of several other modifications described by Clarkson, in this case the elongate calcite prism lenses of Asaphus. 185 However, it is clear that burrowing beneath the sediment or beneath an organic mat does not provide the complete answer because there are genera with reduced eyes (such as Eocryphops) and others that are blind (such as Trimerocephalus), containing species that are highly ornamented and have glabellae with steep front walls. In fact these species are in many respects quite similar to Phacops. Such animals may have lost their sight as a result of a change to detritus feeding. Instead of ~ BLINDNESS | A-C, represents the evolution of the E-G, the schizochroal type with ploughing in the mud, they may have dug shallow vertical burrows, processing the excavated mud for food as did the blind crypto- lithids (Campbell, 19755). The loss of sight in such forms would have been accompanied by the compensating development of olfactory and tactile sensory capacities to a high level. In summary, then, the explanation of blindness is that : (a) The number of lenses was reduced in some species as a result of the increase in the number of rhabdoms per visual unit. This reduction took place in several environments. 186 (b) Species with few lenses could more easily lose their eyes than those with many lenses. (c) Some such species adopted a_ semi- burrowing habit, became smooth, flat and blind, whereas others became deposit feeders that were never completely buried and hence retained their high profiles and strong dorsal ornament. The last hypothesis, unlike many others in this field, is capable of being tested. It is scarcely conceivable that either of the above burrowing types could function with exites as large as those figured by Sttirmer and Bergstr6m for large-eyed Phacops sp. Appendage-bearing blind phacopids should be sought. Burrows are not uncommonly preserved particularly in muddy rocks, but careful observation is needed to distinguish them. And _ finally, scanning electron microscopy of the surfaces of blind forms should be carried out to see if the surface sensory structures are consistent with the habitat indicated. One other interesting point is that since both the outer and inner covering layers on the lenses have a randomly oriented micro-crystalline structure, light entering and leaving the system will be effectively depolarized. Light passing through seawater becomes polarized in various planes depending on the angle of elevation of the sun, but it would become largely depolarized on reflection from the objects in the field of vision of the trilobite. It would not be expected that an organism of this kind would have any use, such as navigation, for polarized light, and hence depolarization would be an advantage. Light from a depolarized parallel incident beam having passed through the upper unit would remain unpolarized because of the radial arrangement of the c-axes of the crystals in this layer. Passage through the central core and the optically continuous intralensar bowl would not repolarize the light because the originally parallel beam would enter it from a variety of directions as a result of the focusing effect of the upper unit. The reason for the thin inner lens layer with its randomly oriented c-axes is therefore obscure. Sexual Dimorphism of Eyes Many phacopid species show dimorphism of many characters. This has been known for many years (Girty, 1899) and the eye dimorphism of both European and American species has been commented upon by Clarkson (1966, 1969), Selwood and Burton (1969), Eldredge (1972, 1973) and Campbell (1968, in press). Many species are represented by two eye types at a single locality, and some are represented by K. S. W. CAMPBELL three. A good example of the former is P. | vaymondi Delo, and of the latter P. birdsongensis Delo. Morphs are most easily distinguished by the number of lens files and the number of lenses per file as is shown by the counts of the lenses of P. raymondi given in Figure 12. That may be other differences as well. Size and structure of the lenses, thickness and height of the sclera, and height of the eye on the cheek are dimorphic in some species but not in others. Moreover some species, such as P. vana show no eye dimorphism. Sarco s Se Ss Ss = J ; — on — | =a =e 38 FiGuURE 12 a, b.—Pattern of lenses in the two morphs © of Paciphacops vaymondi from the Lower Devonian } Haragan Fm. of Oklahoma. (a) shows the lens distribution in eighteen specimens of the large-eyed morph and (b) in twenty specimens of the small-eyed morph. Further details in Campbell (in press). The significance of this is not understood, but a clue may be obtained from a study of P. vaymondt. The large-eyed morph has large perforations through most of the glabellar tubercles, but the small-eyed morph does not. These perforations were probably the sites of | tactile or chemosensory structures. Thus other sensory structures as well as eyes are dimorphic, — and it seems reasonable to conclude that the morphs had different habits, perhaps of | ¢ i" Rat ms THE FUNCTIONAL ANATOMY OF PHACOPID TRILOBITES scavenging or detritus feeding. No attempts have yet been made to examine the optical properties of the lenses of a pair of morphs, but this is obviously desirable. Acknowledgements During the preparation of this lecture I have enjoyed the assistance of numerous colleagues. Dr. R. A. Eggleton and Mr L. Belbin produced the computer simultation of ray paths through the lenses ; Dr. N. Ware did the electron micro- probe analyses; Messrs D. J. Holloway and G. R. Harper prepared the text figures and L. Seeuwen the photographs. Professor G. A. Horridge, Dr. Simon Laughlin and Dr. V. B. Meyer-Rochow have discussed neurobiological problems and have suggested many references to the literature. Professor MHorridge also criticized a draft of the text on the eyes, and suggested many improvements. To all these gentlemen I wish to express my thanks. References Benuam, W. B. S., 1885. Description of the Muscular and Endoskeletal Systems of Limulus. Trans. zool. Soc. London, 11 (2), 314. CAMPBELL, K. S. W., 1968. Trilobites of the Henry- house Formation, Oklahoma. Bull. Okla. geol. Surv., 115, 1. CAMPBELL, K. S. W., 19756. The Functional Mor- phology of Cryptolithus Fossils and Strata, 4, 65. CAMPBELL, K. S. W. (in press). Trilobites of the Haragan, Bois D’Arc and Frisco Formations. Bull. Okla. geol. Surv. Cuiupaé, I., 1966. The Upper Devonian and Lower Carboniferous Trilobites of the Moravian Karst. Sb. geol. ved. paleontol., 7, 1. Cisne, J., 1974. Trilobites and the Origin of Arthro- pods. Science, 186, 13. Cisne, J., 1975. Anatomy of Tviarthrus eatoni (Trilobita) . . . Results of a Radiographic Study. Fossils and Strata, 4, 45. Crarkson, E. N. K., 1966a. Schizochroal Eyes and Vision of Some Silurian Acastid Trilobites. Palaeontology, 9 (1), 1. Crarkson, E. N. K., 19666. Schizochroal Eyes and Vision in Some Phacopid Trilobites. Palaeon- tology, 9 (3), 464. Crarkson, E. N. K., 1967a. Environmental Significance of Eye-reduction in Trilobites and Recent Arthropods. Mar. Geol., 5, 367. Crarxson, E. N. K., 1967b. Fine Structure of the Eye in Two Species of Phacops (Trilobita). Palaeontology, 10 (4), 603. Crarxson, E. N. K., 1969. On the Schizochroal Eyes of Three Species of Reedops (Trilobita: Phacopidae) from the Lower Devonian of Bohemia. Trans. Roy. Soc. Edinb., 68 (8), 183. Crarxson, E. N. K., 1973. The Eyes of Asaphus ey dae Dalman (Trilobita). Palaeontology, 16 3), 425. Crarxson, E. N. K., 1975. The Evolution of the Eye in Trilobites. Fossils and Strata, 4, 7. 187 CLarkson, E. N. K., and Levi-Serti, R., 1975. Trilo- bite Eyes and the Optics of Des Cartes and Huygens. Nature, 254, 663. DALINGWATER, J., 1975. Trilobite Cuticle Micro- structure and Composition. Palaeontology, 16 (4), 827. DoFLein, F., 1904. Ttefsee-Exped. Valdivia, 6, 1. ELDREDGE, N.,1971. Patterns of Cephalic Musculature in the Phacopina (Trilobita) and their Phylogenetic Significance. J. Paleont., 45, 52. ELDREDGE, N., 1972. Systematics and Evolution of Phacops vana (Green, 1832) and Phacops iowensis Delo, 1935 (Trilobita) from the Middle Devonian of North America. Bull. Am. Mus. nat. Hist., 147, 45. ELDREDGE, N., 1973. Systematics of Lower Middle Devonian Species of the Trilobite Phacops Emmrich in North America. Bull. Am. Mus. nat. Hist., Brachyura. Wiss. Evrgebn. dt. 151, 285. Ersen, H. K., 1958. Blinding and Extinction of Certain Proetidae (Tvil.). J. palaeont. Soc. India, 3, 82. FRIEDERICHS, H. F., 1931. Beitrage zur Morphologie und Physiologie der Sehorgane der Cicindeliden (Col.). Z. Morph. Okol. Tieve, 21, 1. Girty, G. H., 1899. Preliminary Report on Paleozoic Invertebrate Fossils from the Region of the M’Alester Coal Field, Indian Territory. U.S. Geol. Suvv., 19th Ann. Rept., 1897-1898, 539. HeEss_er, R. R., 1964. The Cephalocarida, Com- parative Skeletomusculature. Mem. Conn. Acad. Arts. Sci., 16, 1. Huek, P., 1953. Trilobites im Piveteau, J., (Ed.), Traité de Paléontologie, Masson et Cie, Paris, 44. Jocxuscu, B., 1967. Bau und Funktion eines Larvalen Insektenauges—Untersuchungen am Ameisen- l6wen (E£uroleon nostvas Fourcroy, Planip., Myrmel.). Z. vergl. Physiol., 56, 171. KIRSCHFELD, Von K., and REIcHARDT, W., 1964. Die Verarbeitung Stationarer optischer Nachrichten im Komplexauge von Limulus. Sonderdruck. aus “ Kybernetik ’’, 2, 43. Linpstrom, G., 1901. Organs of the Trilobites. Akad. Handl., 34, 1. Meryver-Rocnow, V. B., 1974. of the Larval Eye of the Sawfly, Perga. Physiol., 20, 1565. MILLER, J., 1975. Structure and Function of Trilobite Terrace Lines. Fossils and Strata, 4, 155. Moore, R. C. (Ed.), 1959. Tveatise on Invertebrate Paleontology, Part O, Arthropoda I. Geol. Soc. Am. and Univ. Kansas Press, Kansas. QUENSTEDT, A., 1937. Beitrage zur Kenntnis der Trilobiten, mit besonderen Rucksicht auf ihr bestimmte Gliederzahl. Avch. Naturgesch., 3, 337. ScHRANK, Von E., 1973. Denchkmannites caecus n.sp., ein blinder Phacopidae aus dem héchsten Thiir- inger Silur. Z. geol. Wiss., 1, 347. SELwoop, E. B., and Burton, C. J., 1969. Possible Dimorphism in Certain Devonian Phacopids (Trilobita), im Westermann, G. E. G. (Ed). Sexual Dimorphism in Fossil Metazoa and Taxonomic Implications, E. Schweizerbartsche Researches on the Visual K. Svenska Vetenskh— Structure and Function J. Insect Verlagsbuchhandlung, Stuttgart, Page 196. eR es K. S. W. CAMPBELL STURMER, W., and BeErGstrR6mM, J., 1973. New Discoveries on Trilobites by X-rays. Paldont. Z., 47, 104. WATERMAN, T. H., 1954. Directional Sensitivity of Single Ommatidia in the Compound Eye of Limulus. Proc. natn. Acad. Sci. Wash., 40, 258. WELsH, J. H., and Cuace, F. A., 1937. The Eyes of Deep-sea Crustaceans: I. Acanthephyridae. Silicified Middle Ordovician Trilobites, Biol. Bull., 72, 55. geol. Soc. Am., 59. Department of Geology, Australian National University, Canberra, A.C.T. (Received 30.7.1975) EXPLANATION OF PLATE A Eophacops mushent (Salter) from the Middle Silurian of Dudley, England. Specimen A28671, Sedgwick Muse " Cambridge, England. Specimen photographed under glycerine. Figures 1-3 are x 6-5 approx. ; Figures 4 are 8-5 approx. EXPLANATION OF PLATE B All scale units 0:2 mm. Ficures 1—6.—Phacops vana milleri Stewart, horizon and locality unknown. 36856 Australian National Universi Collection. 1-3. Oblique section through three lenses photographed (1) in unpolarized light; (2) in cro polarized light with the plane of polarization of the analyzer parallel with the vertical edge of the plate (3) in cross polarized light with the plane of polarization of the analyzer at 20° to the left. Note the layerir of the lenses in (1), and the patterns of extinction of the various lens units in (2) and (3). 4. Vertical se _ through two lenses photographed in plane polarized light. t (6) and at 10° to the right in (5). Ficure 7.—Phacops vana Green from the Silica Shale, Ohio. A single lens photographed in plane polarized light. EXPLANATION OF PLATE C Fricures 1, 2.—The eyes of the two morphs of Paciphacops vaymondi (Delo) x4-7 and x9. Haragan Formatio Lower Devonian, Oklahoma. Ficures 3—5.—Three partly silicifed specimens of Paciphacops birdsongensis (Delo), all x16 approx. Formation, Lower Devonian, Tennessee. (3) shows lenses from which the upper unit has been rem but the intralensar bowl and central core are still present. an individual with the corneal membranes removed, and the upper unit is removed medially to reveal tip of the central core. (5) shows lenses on the left with the intralensar bowl still present and the cavity Wuittincton, H. B., 1975. Anatomy and Mo le WHITTINGTON, H. B., and CAMPBELL, K. S. W., WuitTIncton, H. B., and Evitt, W. R., The central core is well shown. Life of Olenoides serratus, Burgess Shale, Columbia. Fossils and Strata, 4. Silicified Silurian Trilobites from Maine. Mus. Comp. Zool., 135 (9), 447. Scale unit is 0-2 mm. _ 5, 6. A lens photogra 11215 Australian National Une Colles Arrow indicates a hollow central core. (4) the base of the core, and sites on the right from which all the lenses have been removed. On all t € specimens the sclera has been removed by; natural weathering. FiGuRE 6.—The eye of a large-eyed morph of Paciphacops bivdsongensis (Delo) X9 approx. Birdsong Shal Lower Devonian, Tennessee. This specimen has the original exoskeletal material present. JOURNAL ROYAL SOCIETY N.S.W. CAMPBELL PLATE A JOURNAL ROYAL SOCIETY N.S.W. CAMPBELL PIATE ER MOURNAL ROYAL SOCIETY N.S.W. CAMPBELL. PLATE C Journal and Proceedings, Royal Society of New South Wales, Vol. 108, pp. 189-202, 1975 Bud Failure of Stonefruits—Some Changes in Development and Chemical Composition of the Flower Buds of Peach (Prunus persica L. Batsch) H. D. R. MatcoL_m AxpsTRACT—Because the failure of reproductive buds of peach increases in their developmental stages from differentiation to bud-burst, its incidence appears to relate neither to stage of develop- ment nor to chilling. Measurements of bud volume, weight, water, respiration and the contents of nitrogen, sugar, protein and amino acids showed that only respiration increased whilst most others decreased following intermediate fluctuation with the onset of failure. Introduction In New South Wales bud drop of peach occurs from March to October ; there being appreciable variation between cultivars and seasons. In average years on the Murrumbidgee Irrigation Areas (MIA) about half the flower buds of | Elberta peach, for example, fail to develop but | im some seasons as many as 90 per cent may fail (Lenz, 1963). Saikia et al. (1967) found 80-90 per cent bud failure to be common in some } almond cultivars grown in the United States. Extensive bud failure has often been attributed to insufficient winter chilling (e.g. Black, 1955 ; Weinberger, 1967). Such failure ‘either from abscission, or necrosis without | abscission, may be observed in early autumn and thereafter increases in severity until flowering. The incidence may vary widely between trees of the same cultivar growing in /adjacent orchards, possibly because of some within-tree nutrient competition ; and between trees of different cultivars which differentiate varying proportions of vegetative and flower buds (Lenz, 1963). Kester (1968) reported that | some bud failure in almond is hereditary and | non-transmissible. Abscission associated with a virus infection has also been suggested (Saikia et al., 1967). Apart from observation that bud | failure occurs most commonly in late winter, | very little is known of its association with | climatic factors, or the degree of proneness to | failure of buds at different stages of development. Although development of buds and shoots of some peach cultivars in particular environments | has been studied, for example the Anzac and | Pullar’s Cling cultivars by Barnard and Read (1932) in Victoria, and the Lovell peach cultivar by Chandler and Tufts (1933) in the United “ States, it was necessary to document the seasonal development of the particular cultivars used in this study. Further, the nature of any disruption of metabolism in the buds may be revealed by following changes in some of their chemical components. The onset of rest of buds in autumn is generally accompanied by a decrease in the proportion of water to dry weight and an accompanying decrease in respiration rate (Kosseva et al., 1968 ; Kozlowski, 1964). When visibly active growth resumes, the water content increases and respiration rate rises ; both changes almost certainly reflect change in enzyme content. Karapetyan (1967) reported seasonal change in carbohydrate content of the buds of almond and peach, and this in turn may be related to bud failure prevalent in trees with low starch content early and low sugar content late in the season. Nitrogen content is reported to increase considerably in the flower buds of peach during bud burst (Radu, 1960) and about one-third to one-half of the nitrogen in buds is translocated back into the shoots before flower abscission (Murneek, 1930). Denny ef al. (1965) found aspartic acid predominant amongst the total amino acids of peach leaves and that arginine, glutamic acid, and alanine were the predominant free amino acids. These changes would be expected in the general sequence involved during bud development from initiation to flower emergence. This paper discusses the development of shoots and flower buds of a typical peach variety (King Edward) grown in the orchard of the Macquarie University, Sydney. Data are also given of low-temperature requirements for breaking of rest of this cultivar and of two 190 Lc eB a others, one in the same orchard and the other grown on the MIA. The study was undertaken to examine these changes and make comparisons between healthy (viable) and _failure-prone (abscissing) flower buds. The three peach cultivars compared were Edward VII, commonly called King Edward (KE) a cultivar very similar to Watt’s Early; Blackburn (BB), another freestone type grown in the mid-coastal regions of N.S.W. (Holbeche, 1966) ; and Golden Queen (GQ) the main clingstone cultivar grown inland for processing (Malcolm, 1965). Experience of commercial growers has indicated that the chilling requirements of these three cultivars increase in the order KE, BB and GQ. Some incidence of bud failure was suspected but not definitely known in KE and BB, whereas GQ was known to be prone to bud failure. Materials and Methods Mature 15-year-old trees of the KE and BB cultivars were available in the University orchard, but to include GQ for comparison under similar conditions three-year-old trees of each cultivar, potted and adequately fertilized, were grown in the University glasshouse. Two orchards in the MIA were selected to study gross samples of GQ buds, one at Yanco where very little bud failure was known to occur and the other at Stoney Point where bud failure was a long recognized problem. Generally, whole branches were cut from the trees to provide samples for analyses, and taken to the laboratory where buds and shoots were removed, measured, weighed, and frozen. The frozen samples were dried to a constant weight on a Vertis freeze-drier, thus providing data on moisture content and material for chemical analyses free from enzyme action. Temper- atures in the orchards and glasshouses were recorded continuously. Shoot growth, and chilling: Periodicity of shoot growth was studied by measuring five new terminal shoots on each of four trees from the time they commenced to elongate in early spring. To assess termination of rest in winter, shoots similar to those being measured were cut periodically and placed with their cut ends immersed in water in an incubator maintained at 22°C. About 5 mm of wood was cut from the immersed ends of the shoots after five days to maintain water uptake, and the number of flower buds which had opened after a further five days was recorded. The chilling require- ments of these shoots were taken to have been satisfied when at least 40 per cent of the buds had opened. MALCOLM Bud failure and histology: Samples of bud primordia and flower buds were harvested at all stages of growth and development. They wer separated into viable and failure-prone, the viable buds being those firmly attached to the. twigs whereas the failure-prone buds were only loosely attached, could easily be removed, and showed browning around the periphery of the )) 1!) abscission zone at the base of the bud. They were fixed in FAA (formalin: acetic acid: }) Ii ethanol: water—5 : 5 : 68 : 27) dehydrated # aw through an ethanol/tertiary butyl alcohol/ paraffin oil series, infiltrated with wax under vacuum, and embedded according to the method |) ¢; of Johansen (1940). Serial sections were then |) jj cut at 8-10 ym thickness on a Spencer rota ain microtome, and stained in aniline blue a alo safranin, using the method of Conn e¢ al. (1960). ¥) j., Respiration a The ends of sections of fresh shoots (10-15 em |) ml long) with intact buds were coated with molten }) iin paraffin wax and placed in a respiration chamber }) atv at 22°C. Oxygen consumed by the shoots a tnt buds was monitored by a calibrated Mackereth |) #e oxygen electrode connected to a 10 mV recorder (hs (Mancy and Westgarth, 1962). After a constant }}) sm rate of oxygen consumption was attained eI rei shoots were removed from the chamber and the |) jy buds were excised at their abscission layers. The wounds on the shoots were coated with paraffin wax, and the shoots were then returned to the chamber and left until a constant rate of oxygen uptake was again indicated. Oxygen consumed by the buds was calculated from the difference between the two rates. Sugar Sugar was extracted from freeze-dried buds, } leaves, and shoots, in 75 per cent ethanol in an Ultra Turrax homogenizer. The homogenate was centrifuged for 10 minutes at 2,500 ee a, the supernatant decanted, dried in a rote vacuum evaporator, and finally taken up in 4 ml 1 10 per cent isopropanol. Total sugar as determined by Benedict’s Test (Harper, 1967) using glucose and fructose standards at 535 nm in a_spectrophotometer. Total sugar w separated into components by chromatograp on Whatman No. 1 paper in n—butanol : acetic acid; water (12:3:5) followed by pheno 2 water (4:1). Chromatograms were developed by both the silver nitrate/sodium hydroxide’ method of Trevelyan ef al. (1950) and by aniline phthalate spray (Smith, 1958). Chemical tests for glucose, fructose, sucrose, and ribose were made by the methods of Harpe . BUD FAILURE OF STONE FRUITS (1967). Similar tests for reducing sugars were made following invertase treatment, and also by the Seliwanoff test (Oser, 1965). Further identification of the sugars was made by gas- liquid chromatography (GLC). Nitrogen Total nitrogen in the buds was determined by the micro-Kjeldahl method described by Oser (1965) in which duplicate 0-2 g samples of ground and freeze-dried buds were analysed. Amino Acids Ground freeze-dried samples (each 1 g DW buds) were extracted first by boiling for three minutes in 100 ml 80 per cent ethanol and allowing to stand for 10 minutes, the supernatant decanted, and then a further 100 ml boiling 20 per cent ethanol added to the residue. After a further 10 minutes the two supernatants were combined, and reduced under vacuum to about 50 ml (Smith, 1958). The concentrated aqueous extracts were washed with 100 ml acetone containing 1-0 ml 10N HCL, followed by 100 ml ether to remove salts, chlorophyll, and fats (Cassidy, 1957). The extracts were finally evaporated to dryness under vacuum and the residues taken up in 0-5 ml 10 per cent isopropanol. Aliquots (each 20 ul) of the extracts were separated on Whatman No. 1 chromatography paper (2525 cm), ascending in two dimensions in standard solvents followed by development with ninhydrin. The developed spots were cut out and eluted in 10 per cent isopropanol, following which the coloured solutions were compared with standards in a spectrophotometer at wavelengths of 450 and 570 nm (Moore and Stein, 1948). Protein One-gram samples of freeze-dried buds were extracted by grinding in 6-0 ml sucrose/ phosphate buffer pH 7-0 at 0°C (Evans et al., 1963), to which one per cent Polycar AT (an inert cross-linking insoluble form of polyvinyl- pyrrolidone) was added to remove tannins and anthocyanins and to prevent precipitation of the proteins (Jaarsveld and Meynhardt, 1967). The homogenates were later centrifuged for 30 minutes at 10,000 g and 5°C. The super- natant was decanted, a portion used to determine the total soluble protein by the Lowry-Folin method (Oser, 1965), and the remainder subjected to acrylamide gel electrophoresis (Rogers, 1965). The Rf values of the stained protein bands were calculated by measurement against a lighted opalescent screen, photo- 191 graphed, and later scanned at 600 nm in a densitometer. Further extracts for comparison were run through a DE-32 cellulose column eluted with 0-02M tris-buffer containing a NaCl salt concentration gradient from 0-1M. The absorbance of each 5 ml fraction collected was read in a spectrophotometer at 280 nm. Approximate molecular weights of the main protein fractions were calculated following fractionation on Sephadex G-100 and on polyacrylamide gels (Anon, 1968 ; Hedrick and Smith, 1968). Comparative levels of 14 mineral nutrients in buds and leaves were determined using the techniques and equipment described by Leece (1967) for routine leaf analyses. Results Shoot growth : The growth record for KE in the University orchard during the 1967-68 season showed that the terminal shoot underwent two periods of elongation. The growth rate accelerated as daily temperatures increased during spring, but decreased after mid-October, when flower bud initiation began. A second shoot elongation accompanied the initiation of axillary buds but this ceased at the end of December long before flower primordia were visible. Unfolding of leaf buds on the shoots did not appear to be closely related to shoot elongation. Flower initiation : Most flower buds appeared to be initiated as lateral buds of a central vegetative bud. They were borne only in the axils of leaves on current season’s shoots, singly or in pairs, and sometimes in threes. Triplet bud formation, that is, a central leaf bud with a reproductive bud on either side (Plate Id) was observed in the central region of vigorous shoots. These vigorous shoots attained a diameter of 3-8 mm by the time bud differentiation began. Often a third reproductive bud arose below the central leaf bud. Of all three cultivars (KE, BB and GQ), irrespective of location, branches which produced weak shoot growth also produced predominantly single flower buds. When these buds are clustered around the tips of the shoots, a characteristic commonly referred to by growers as “‘tip-bearing’’, it causes poor fruit yields. Such buds initiated immediately behind the shoot tip appear to develop directly into flower buds. On more vigorous shoots, however, 5-10 mm diameter, where these single buds immediately below the tips are commonly reproductive, further single buds borne in the basal regions on those shoots are invariably 192 vegetative. Despite similar patterns of shoot development found for all three cultivars in their respective orchards, only KE and BB were similar to their orchard-grown counterparts when grown in the glasshouse, whilst all three cultivars differed in times of their individual stages of development. Bud growth and differentation: A detailed study was made of growth of buds of KE, the sequence of growth and the histology of develop- HiD; (R..MALGOLM but on GQ bud burst occurred some two months _ after differentiation (Plate IIj). When com- pared with orchard temperature records this corresponded with the completion of sufficient — exposure to low temperature or chilling. q Bud abscission and necrosis : In the University — orchard, bud failure was greatest on KE and BB in 1967, and on GQ at Stoney Point in 1969 (Table 2). Many of the buds died im sitw and did not absciss due to necrosis of their flower esa BS en — — ee ~~ ment of the buds is described in Table 1. It is initials (Plate Ib). Trees growing in the TABLE 1 Summary of Shoot and Bud Growth Stage of Shoot Growth Growth and Histology of the Buds Reference Ih Flowering, closely followed by vegetative growth on one-year-old woody shoots. These shoots slowly increased in diameter but not in length (i) Initiation of reproductive buds began iust before the second flush of the vegetative growth (ii) Number of leaves increased until about time of fruit ripening (ili) Shoot tips continued elongation until about the end of December (iv) Side shoots on the one-year-old wood also ceased growth (v) Bud differentiation. The growth of the reproductive buds was sufficiently advanced so that triplet bud formations, that is, a vegetative bud with a reproductive bud on either side were clearly visible in the axils of the leaves on the longer shoots (vi) Defoliation (leaf-fall) (vii) Reduced rate of bud expansion with onset of winter conditions (viii) and (ix) The buds began to expand rapidly. Pink petals showed through the tips of the bud scales in what is known as the “ pink ”’ stage pre-flowering. Plate No primordia found in the axils of the leaves Nil 0 Late October— > 975 | 1023) 898 Glasshouse 90-0 Nil 90-0 100 > 159*| 50*} + * heated in winter. +=no data. Under glasshouse conditions where less chilling Was experienced than in the orchard, more | triple-bud formations were found on the shoots of BB than on KE. However, with the shortest chilling requirement, KE differentiated more buds per shoot than the other two varieties. For the three cultivars studied there was an | inverse relationship between the duration of the vegetative growth preceding bud differentiation } and the chilling requirement of the cultivar. The length of time required for the further development of flower buds from differentiation to bud burst, was in proportion to this chilling requirement. Bud growth: There was a rapid rise in dry weight of KE buds in both 1967 and in 1968 (Figure 1) shortly after differentiation, then only a slow increase from early March to mid-May This was followed by a reduction in dry weight before a final rapid increase at bud burst. Some 30 to 45 per cent of the dry matter of the buds to pee of leaf-fall was therefore lost before bud urst. orchard just before bud burst (Figure 2) was associated with a high percentage failure (Table 3). Respiration : Respiration rates during early bud growth and dormancy were about 300 to 400 ul oxygen per gram dry weight per hour (Figure 3). Assuming a mean respiration of 365 ul O,/gDW/hr for KE buds, for example in the April to June period, the loss of weight would have been equivalent to about 14 mg carbo- hydrate. Since the actual loss in bud dry weight during this period was 16 mg, assuming no further import of carbohydrate from the twig in dormancy, most of this loss could be caused by respiration. The failure-prone GQ buds from the Stoney Point orchard had a lower respiration rate than the Yanco orchard buds in April and May. However, the rate for Stoney Point GQ buds then increased markedly during the winter, long before bud burst, and at a time when both dry weight and water content increased slowly. Bud sugar : The mean sugar content of shoots of the three cultivars is shown in Table 4. 194 TABLE 3 Volume, Dry Weight, and Failure of Buds of the Three Cultivars Cultivar, Orchard Apparent Volume in Mid- and Year June (cm$) KE-—Macquarie 1967 0-023 KE-—Macquarie 1968 0-043 BB—Macquarie 1969 0-085 GQ-Yanco 1969 0-065 GQ-Stoney Pt. 1969 0-053 Shoots with few flower buds had low sugar content, indicating a relationship between carbohydrate metabolism and number of buds per shoot. There was, however, no difference in composition of the sugar in the two types of shoot. Not only was this found to consist of glucose plus fructose in the ratio of approxi- mately 2 : 1 in extracts of the shoots, but also in relatively pure exudates from glands on the leaves. A considerable amount of sugar was exuded by leaf glands of BB and GQ trees TABLE 4 Sugar in the Peach Shoots Sugar Number of Sample Content | Flower Buds (All Buds Removed Before | (Per cent Formed Extraction) of Fresh per cm Weight) Length of Shoot GQ shoots with many buds 1-02 2-0 GQ shoots with few buds 0-49 0-2 BB shoots with many buds 0-84 ey BB shoots with few buds 0-57 0-3 KE shoots with many buds 2-00 2-2 KE shoots with few buds iMe7is) 0-6 growing in the glasshouse. The concentration of the exuded sugar was considerably higher, about 2:0 M, than the calculated 0:25 M in shoots, buds, and in discs cut from leaves. No sucrose was detected in any of the analyses. Sugar in the buds of GQ in both the Yanco and Stoney Point orchards continued to increase from leaf-fall through dormancy until bud burst (Figure 4). Nitrogen : Nitrogen was lowest in the KE buds in the University orchard in both 1967 and 1968 (Figure 5) at time of differentiation, thereafter increasing to a maximum at bud burst. Nitrogen increased more rapidly in April-May 1968, but fell more slowly than in 1967. Fewer analyses were made on GQ than on KE. Similarly Stoney Point GQ _ buds H. D. R. MALCOLM Dry Weight in Mid- Per cent Failure June (mg) eee By Abscission | By Necrosis 22 7-5 2-0 25 0-0 0-5 25 13-5 4-5 23 4-0 1:5 19 54-0 2°5 accumulated nitrogen earlier in dormancy than the Yanco orchard GO buds. The Yanco buds also accumulated metabolites more rapidly on approach to bud burst than did the Stoney Point buds. Amino acids: The concentrations of six out of eight major amino acids found in the KE buds increased around time of differentiation (Figure 6a). Only aspartic and glutamic acids © decreased in parallel with total nitrogen. The — amides of these two acids, asparagine and ~ glutamine, each increased about three-fold at the same time. Arginine was the predominant amino acid, both at differentiation and at bud burst. There was a general reduction in content — of amino acid about time of leaf-fall, which at — that stage corresponded with the general rise in total bud nitrogen. The quantities of all eight major amino acids increased sharply at bud burst, the same pattern being found in the GQ buds at Yanco in 1969 as in the KE buds in the University orchard in 1968 (Figure 6, a—b). — Traces of serine, glycine, cysteic acid, lysine, threonine, valine and the leucines were also found, but mainly at bud burst ; their quantities — being insufficient for accurate measurement. Soluble: protein: Soluble protein in the KE buds increased sharply around time of differ- entiation, the increase occurring earlier in 1967 than in 1968 (Figure 7). Concentration of bud protein fell generally during late autumn and early winter, but rose again well before bud — burst. A similar sequence was found for GQ — which had a correspondingly higher level of protein in viable than in failure-prone buds. Three major fractions of soluble protein of — approximate molecular weights 10010%, — 26 103, and 4-4 108 respectively, differed in — extracts of viable and abscissing buds of the — BB cultivar (Figure 8). There was more — protein of MW 26 x 103 (Fraction 2) and less of | MW 100 «103 (Fraction 1) in abscissing than in — viable buds. Both the total soluble protein, — and the number of fractions separated on — TABLE 5 Mineral Nutrients in the Leaves and Flowev Buds ppm ; ppm ppm |; ppm 37 Mo ppm Fe ppm BUD FAILURE OF STONE FRUITS 195 59 71 22 54 19 52 42 56 26 87 38 62 12 17 19 25 17 285* 24 27 36 19 24 rooonts DDDMDAINS WIAs Oa Mineral Nutrients HONONS rOMONN OND OS ANDEr OO leaves leaves buds buds buds at bud-burst Orchard Stoney Pt. Stoney Pt. Yanco Stoney Pt. Yanco Yanco * High level thought largely due to application of a copper oxychloride spray five days prior to bud sampling. polyacrylamide gels, increased most between initiation and differentiation of the buds than in the later stages of development when some further fractions appeared. Some of these fractions were absent from extracts of the abscission-prone buds. Mineral nutrients : There was a gross difference between levels of only one of the 14 nutrients compared (Table 5), molybdenum being much higher in the buds where the incidence of failure was high. Discussion Differences in growth between the three cultivars appeared to be correlated with the duration of exposure to low temperature required to break their dormancy. This determined not only the length of the dormant period but also whether growth activity, expressed as expansion of the flower buds, commenced in late winter or early spring. Between 600 and 900 hours exposure below 7°C is reported necessary for most peach cultivars grown commercially in the United States (Anon, 1941). However, the duration of active shoot extension may also be restricted despite wide differences in the times of commencement of growth. There is therefore a _ period of vegetative growth limited by the requirement for winter chilling. If the period of decreased bud expansion related to ‘deep organic dormancy”’ (Weinberger, 1967) is prolonged because of insufficient chilling, there is excessive bud failure and restricted spring growth. This was very much the effect recorded for GQ grown in the glasshouse. Knowledge of relative stages of extension growth and chilling requirements of cultivars thus assists in determining times of initiation and differentiation of the buds. Stages of development in_ differentiation, however, appear to parallel closely the early findings of both Barnard and Read (1932) and Chandler and Tufts (1933), and more recently Stadler and Strydom (1967). The first mature vegetative growth apparently provides the photosynthetic activity necessary to support the early development of the fruit, and the second flush of growth supports expansion of the fruit following pit-hardening. This may explain too, why the sugar secreted by leaf glands ceases after the first growth flush (Malcolm, 1970) ; it probably then being diverted into the expanding fruit. Hladik (1967) showed that bud failure may result when leaf area is inadequate to support both fruit and new bud growth. If this is so, relatively fewer flower buds would be expected on the trees following a heavy crop year. 196 FIGURE’ BUD WEIGHT AND /‘fesh wt. nibs WATER CONTENT [M.water/dry wt. a) KE- 1967 60+150 ; A Weight (mg) Bud wt (mg) and water content (as °/ DW) Bud volume Ficure 2.—Bud weight, water and volume (GQ 1969). water content 407100 20 60+150 Water content Jas per cent of dry weight Jan Feb Mar = Apr May Jun Jul Aug TIME OF YEAR FicurE 1.—Bud weight and water content. cicure 2 --:BUD._ WEIGHT, WATER, AND VOLUME (GQ 1969) ° 300 200 « leaf fall = == Apr 8 May 7 Juni6 Time of year AUS 29 0.12 m: Yanco GG. e = Pr Ga —= Stoney (0H ree Nn — a [hour Pay Respiration. ml oxygen/g DM, ee a 2.5 ane co) = ul 1,0 0.5 60 50 20 10 H. D. R. MALCOLM BUD RESPIRATION FIGURE 3 Feb Mar Apr May Jun Jul Aug Time of year FicureE 3.—Bud respiration BUD SUGAR CONTENT FIGURE 4. 8 if 16 Apr May Jun Sample date Ficure 4.—Bud sugar content. 23 Aug BUD FAILURE OF STONE FRUITS 197 180 BUD NITROGEN ° FIGURE 5 16 140 = © 120 a ? 100 z WwW oO 3° « & 80 Zz 60 \, N ss 40 it i ty 2 ey oe 20 a? See aeeeere® i ° et) = Sample date Feb Mar Apr = May Jun Jul Aug Sep FiGuRE 5.—Bud nitrogen. AMINO ACIDS IN THE BUDS FIGURE 6. a) University orchard KE 1968 ee pce rea .—sgiutamic Togs on pg eg -—*glutamine ass proline if 5 Zeki ot s 4 Va aly ie / / S : Sa Tae ay 2 3—v —3 759 Feb Mar Apr May Jun Jul Aug FebMar Apr May Jun Jul Aug b) Yanco GQ 1969 10 = a 5 = =e >— x: 0. Apr8 May 7 Juni6é “a Apr8 May7 Jun16 Aug 28 c)Stoney Point GQ 1969 10 q 5 rg ale Apr8 May7 Jun 16 Aug 28 Apr8 May 7 Jun16 Aug 28 Sample date FiGurRE 6.—Amino acids in the buds. FIGURE 8. SOLUBLE PROTEIN FIGURE 7. 25 200: 8 2 2, ge at of a S| aA o os! go Se 2! x ep 150 < sail i 2 “\ 17 e ¥ \ y ee a E 10 5 Sample date Ficure 7.—Soluble protein in the buds. FRACTIONATION OF SOLUBLE PROTEIN = FIGURE 8. a) Densitometer graph of acrylamide gel 8 wo w LJ) ro S i} a < viable buds ee mn failure-prone buds 0.44 | of | na = ha E | tail b) Bud extract run on 1x15cm 8 034! ler column of DE-32 cellulose Seal nae eluted with NaCl gradient in % | ; 0.02M tris buffer eo E02 £0. a - ° w oO = 0.14 ml. effluent Fractionation of soluble protein from buds. 198 H. D. R. MALCOLM Although the incidence of bud failure during the three seasons of this study was not exceptionally high, both abscission and necrosis of buds were recorded in each year from April onwards—that is, shortly after commencement of differentiation of the basic flower parts. The reproductive buds which were initiated at distinctly different times on the three cultivars, all reached differentiation at much the same time in March. Thereafter the only major processes to be completed before flowering were the relatively prolonged differentiation and development of the pollen and ovule. It may well be that a certain degree of chilling is essential for this process. Any delay in this, and its associated balance of growth substance, would almost certainly explain poor flowering and fruit set (Luckwill, 1963). Necrosis and abscission, which often occur before differ- entiation of the ovule, would then appear more dependent upon other metabolic processes taking place in the buds. A relationship between bud failure and chilling was evident on both KE and BB in the University orchard in 1967 and 1969. In those years there was less chilling than in 1968 when the bud failure was only slight. The usual form of bud abscission is well documented in the literature and the abscission layer formation is common to many fruits and leaves. The other form of abscission, however, originating in the cortex of the shoot is unusual and may be associated with virus infection. Trees in the orchard at Stoney Point where this form of abscission was prevalent, were shown by plant pathologists of the N.S.W. Department of Agriculture to be infected by Prunus necrotic ringspot and greasy sunken mottle viruses. Most of the failure observed in this study, however, involved abscission of the buds and only a minor proportion was necrotic and did not absciss. Failure to break dormancy as a consequence of inadequate chilling could not be greatly implicated because the evidence suggests that the chilling experienced under the respective orchard conditions was more than adequate. The extent to which buds absciss or die varies greatly within cultivars in different years, suggesting also some disruption of metabolism not associated with the above factors ; a con- dition akin to but not as stable as that described by Kester (1968) as “‘ genetic ”’. Total nitrogen in GO buds in mid-June, 1969, was about 20 mg/g DW at Yanco and about 25 mg/g DW at Stoney Point. The soluble protein plus the amino acids, included because they are sparingly soluble in aqueous buffer, only amounted to about 75 mg/g DW of the Yanco buds and 70 mg/g DW of the Stoney — This protein plus amino acids | Point buds. would thus account for about 11 mg and 10 mg (55 and 40 per cent) of the total nitrogen in the © GQ buds from the Yanco and Stoney Point — orchards respectively. These amounts are in ~ close agreement with the 42 per cent soluble organic nitrogen in the stems of dormant peach reported by Davidson and Shive (1935). That is, about half of the nitrogen in the buds was unaccounted for and was presumably associated with other nitrogenous components such as nucleic acids, nucleotides, and insoluble protein. Sugar contributed 51 mg/g and 46 mg/g (5-1 and 4-6 per cent) towards the dry weights of the Yanco and Stoney Point GQ_ buds respectively. At this time, starch content of the buds would be expected to be relatively low. Twenty per cent of the contents of the buds was therefore unaccounted for by the analyses made in this study. Fats and waxes comprised about 15 per cent (as a residue of methanol extraction) and there was in addition insoluble cellulose and similar compounds. Although changes in the more important labile metabolites were studied, interpretation of the data was limited by uncertainty concerning the remainder. Despite these limitations it was clear that while the apparent volume of the buds increased markedly throughout the whole period of winter rest the dry weight increased only slightly. This increase in dry weight continued until about six to eight weeks prior to bud burst, indicating inflow of nutrients into the buds for some time after leaf-fall. Such inflow of nutrients should have been similar in the two GQ orchards but the buds were relatively smaller on the trees at Stoney Point when compared with buds at a similar stage of development at Yanco. Saikia et al. (1967), however, found that loss of viability in small buds of almond was accompanied by a decrease in the fresh weight, but this was in turn caused by anatomical abnormalities in the eumeristems in late summer. Respiration rates of the abscissing buds did not show the 10- to 20-fold increase found in the normal buds preceding bud burst. Kosseva et al. (1968) found a similar pattern of change for buds of Rosa damascena L. which were undergoing abscission. In their study single buds of about 0-25 g FW respired at 0-15 mg CO,/hr at onset of abscission (equivalent to a reduction from 308 to 96 ul CO,/g FW/hr). When the respiration rates of the GQ buds at Yanco were compared with those of the GQ © buds at Stoney Point in April a similar difference was found although no appreciable bud BUD FAILURE OF STONE FRUITS | abscission had occurred in either orchard at that time. The same ratio between the respiration | rates was again found at bud burst when the incidence of failure was high in the Stoney Point | orchard. Such a rapid increase in the rate of respiration at bud burst is obviously related to the expansion of viable buds and their probable increase of enzymes in comparison with the slower rates of increase in buds destined to fail There was little difference between the concentrations of sugars in the GQ buds at Yanco and at Stoney Point. The composition | of the sugar, however, conflicts with the report of El-Mansy and Walker (1966) that fructose is | the main sugar in peach. Glucose was the predominant sugar not only in the flower buds but also in the leaves, the total sugar being made up of glucose plus fructose. This finding supports Baldwin’s (1963) report that peach buds contain both glucose plus fructose, but no sucrose. Because less sugar was found in twigs which supported few reproductive buds com- pared with twigs with many buds, it is also possible that some conversion of starch to sugar is associated with the increased meristematic activity. The rapid accumulation of sugar in buds following leaf-fall supports the data of Barnard and Read (1932) and Dowler and King (1966), and almost certainly is the result of transformation of starch to sugar in response to low temperature (Barker, 1936). GQ buds in the Stoney Point orchard increased in respiration rate earlier than the buds at Yanco which could further be ascribed to this change if the appear- ance of the necessary enzymes could be explained. All of the eight major amino acids found in the buds in this study have been reported by Durzan (1968) to increase in concentration at bud burst. Arginine and its analogue y-aminobutyric acid were the predominant amino acids found, which agrees with the data of Taylor (1967). Some amino acids even at low concentrations are capable of inhibiting plant growth and causing specific morphological alterations. Significantly, many of these inhibitory amino acids have been related to aspartic acid metabolism (Dunham and Bryan, 1969). It appears possible that some small protein fractions present in failure-prone but lacking in viable buds could be composed of these inhibitory amino acids. The main changes in the chemical components associated with buds destined to fail in the spring were, therefore, a higher rate of respiration from about two months preceding bud burst, a lower concentration of soluble protein and amino 199 acids, and a relatively slow increase of aspartic and glutamic acids and their amides. Certain protein fractions also diminished in the failing buds, and of these, the fraction of high molecular weight around 100 x10% was reduced, possibly by hydrolysis, at the onset of bud failure. This does not, however, explain the large amount of protein of molecular weight around 26 x 103 associated with abscissing buds unless it includes the aspartic and glutamic acids and their amides. Neither could its presence be attributed solely to virus, although the involvement of virus with bud failure is suspect. The same fractions were found in both viable and abscissing buds of all three cultivars studied. The changes in chemical composition specific to buds about to absciss may be summarized therefore as, early burst in respiration, slow increase in sugar, low nitrogen, low level of soluble protein, and low amino acid content, all of which could cause, or be caused by, retarded growth of the buds. Leaf analyses, at a vegetative phase of growth around time of differentiation before bud failure was evident, failed to reveal any significant difference between mineral nutrition of trees and their proneness to bud failure. Some differences in mineral elements have been reported in association with imbalance of growth regulating substance such as indoleacetic acid by Ben- Yehoshua and Biggs (1970). Changes in concentration of some _ growth regulating substances are also known to be associated with bud failure of peach (Malcolm, 1972), and they may further be linked with changes in enzyme activity as suggested by Krupnikova (1967). The relatively high level of molybdenum in the buds prone to failure defies explanation unless the increase in metabolism in viable buds at bud-burst results in its transport out of those buds to other parts of the trees. Summary The reproductive buds of peach are initiated in spring during a temporary decrease in the rate of vegetative growth, possibly in response to some internal nutritional diversion. The buds need a certain amount of chilling for breaking their “rest” but this is usually adequate and unrelated to their failure. Pro- longed chilling delays flowering and shortens the period for vegetative growth. Failure of the buds, from either abscission or necrosis, can occur at any stage of their development its incidence being mild up to differentiation then increasing in severity up to bud-burst. Volume, weight and the contents of nitrogen and sugar in the flower buds all increase from 200 initiation until mid-winter when there is a transient decrease followed by a rapid increase. Respiration also increases from this stage on approach of bud-burst. Failure-prone buds show an earlier increase in rate of respiration than normal buds and a slower rise thereafter, and levels of nitrogen, protein, sugar and particularly aspartic and glutamic acids and their amides are lower. Acknowledgements The assistance of Miss J. S. Railton and Mr. G. J. Rich during this study is gratefully acknowledged, and the Chemistry Branch of the New South Wales Department of Agriculture for the analyses of mineral nutrients. References Anon, 1941. Effects of Climatic Factor: on Growing Plants. In Climate and Man Yearbook of the United States Department of Agriculture. (Eds.), Hildreth, A. C., Magness, J. R., and Mitchell, J. W. Anon, 1968. Sephadex. Instructions for the Gel Filtration Kit. Jan. 1968-1. Chemicals, Uppsala, Sweden. Batpwin, J. G., 1963. Dormancy in Deciduous Fruit Trees and Vines. Proc. 2nd Aust. Fruit Res. Conf., 9:3:1. Published by CSIRO Mel- Pharmacia Fine bourne. BarRKER, J., 19386. Analytic Studies in Plant Respiration. Pyvoc. Roy. Soc. Biol., 119, 453. BARNARD, C., and Reap, F. M., 1932. Studies on Growth and Fruit Bud Formation. IV. Apricot and Peach. J. Vict. Dept. Agric., 30, 28. BEN-YEHOSHUA, A., and Bices, R. H., 1970. Effects of Iron and Copper ions in Promotion of Selective Abscission and Ethylene Production by Citrus Fruit and the Inactivation of Indoleacetic Acid. Plant Physiol., 45 (5), 604. Brack, M. W., 1955. The Problem of Prolonged Rest in Deciduous Fruit Trees. Rept. 13th Intl. Hort. Congr. London, 1122. Cassipy, H.G., 1957. Technique of Organic Chenustry Vol. X. Fundamentals of Chromatography. Inter- science Publishers Inc. N.Y. Arnold Weissberger, Ed. CHANDLER, W. H., and Turts, W. P., 1933. Influence of the Rest Period on Opening of Buds on Fruit Trees in Spring and on Development of Flower Buds of Peach Trees. Proc. Amer. Soc. Hort Sci., 30, 180. Conn, H. J., Darrow, M. A., and Emmet, V. M., 1960. Staining Procedures. The Biological Stain Commission. Williams and Wilkins Co., Baltimore, U.S.A. Davipson, O. W., and Suive, J. W., 1935. Deter- mination of the Nitrogenous Fractions in Vegetative Tissues of the Peach. Plant Physiol., 10, 73. DENNEY, A., WALKER, D. R., and Norton, R. A., 1965. A Study of Selected Biochemical Con- stituents in Certain Prunus Species. Proc. Amer. Soc. Hort. Sci., 89, 140. Dower, M. W., and Kine, F., 1966. Seasonal Changes in Starch and Soluble Sugar Content of Dormant Peach Tissues. Pvoc. Amer. Soc. Hort. Scz., 89, 80. H. D. R. MALCOLM Dunuam, V. L., and Bryan, K., 1969. Synergistic Effects of Metabolically Related Amino Acids on the Growth of a Multicellular Plant. Plant Physiol., 44 (11), 1601. Durzan, D. J., 1968. Nitrogen Metabolism of Picea Glauca. I. Seasonal Changes of Free Amino Acids in Buds, Shoot Apices and Leaves, and the Metabolism of Uniformly Labelled C—L—arginase by Buds During the Onset of Dormancy. Can J. Bot., 46 (7), 909. E.-Mansy, H. I., and Waker, D. R., 1966. Bio chemical Changes Occurring in Apricot and Peach Buds During their Rest Period. Pyroc. 17th Intl. Hort. Congr. Md. 1, Abstr., 510. Evans, W. J., Woopuam, A. A., Carney, W. B., DecHarRy, J. M., and Artscuut, A. M., 1963. Fractionation of Particulate Proteins of the Peanut Cotyledon. Proc. Seed Protein Conf. New Orleans, 218. Harper, H. H., 1967. A Review of Physiological Chemistry. 11th Edn. Lange Medical Public- ations, Los Altos, California. Heprick, J. L., and Smirn, A. J., 1968. Size and Charge Isomer Separation and Estimation of Molecular Weights of Proteins by Disc Gel Electrophoresis. Arch. Biochem. Biophys., 126, 155. Hvapik, F., 1967. Fertility as a Factor Influencing the Growth and Productivity of Peach Trees. I. The Influence of Fertility on the Growth and on the Differentiation of Flower Buds. Ved. PR. Ovocnarske vyzk ustav ovacnarsky. Vousich, 3, 51. HoLtsBecuE, J. A., 1966. Peach and Nectarine Growing. N.S.W. Dept. Agric. Hort. Bull. 121. JAARSVELD, P. P. vAN, and MEYNHARDT, J. T., 1967. The Effect of Carbowax on the Activity of Indolea- cetic Acid Oxidase from Peach Leaf Tissue. Sith. Afr. J. Agr. Sci., 10 (4), 901. JOHANSEN, D. R., 1940. Plant McGraw-Hill, London. KARAPETYAN, K. A., 1967. Dynamics of Changes in the Carbohydrates in the Buds of the Almond and Peach in Connection with their Frost Resist- ance. Biol. Zh. Avm., 20 (8), 58. Kester, D. E., 1968. Noninfectious Bud Failure, a Nontransmissible Inherited Disorder in Almond. I. Pattern of Phenotype and Inheritance. Proc. Amer. Soc. Hort. Sci., 92, 7. Kosseva, D., ZoLorovicu, G., and DEcHEVA, R., 1968. Study on Flower Buds of Rosa Damascena Mill. in Conjunction with their Falling Off. Rastenevod. Nauki, 5 (2), 31. Koztowsk1, T. T., 1964. Water Plants. Harper, New York. Krupnikova, T. A., 1967. Enzyme Activity Affected by Zinc Deficiency. (Transl.) | Mikroelem. Biosfere Ikh. Primen. Sel, Khoz. Med. Sib. Dal’nego” Vosloka, Dokl. Sib. Kouf. 2nd 1964, (Publ. 1967), pp. 318 (Russian). LEPGE, DL ire L96 Te Diagnosing Malnutrition in Peach Trees. persica L. TBatsch) M.Sc.Agr. thesis. University of Sydney. Lenz, F., 1963. Flower Initiation and Development: of Stonefruit Varieties in the Murrumbidgee Irrigation Areas. Proc. 2nd Aust. Fruit Res. Conf. Ovange and Terrigal, N.S.W., 9 (13), 1. Lucxwitt, L. C., 1963. Some Aspects of the Physiology of Reproduction in the Apple. Proc. 2nd Aust. Fruit Res. Conf. Orange and Terrigal, NS Gee Microtechnique. Metabolism in Leaf Analysis as a Guide in (Prunus The (d)\ JOURNAL ROYAL SOCIETY N.S.W. MALCOLM PLATE I Plate I (a, b.)—Abscission zone at base of bud peduncle. (c) Unusual abscission zone in shoot cortex. (d) Vegetative bud with reproductive buds on either side. (e) Necrotic flower buds and early shoots of vegetative bud growth. M PLATE WS LAALCOL J AL ROYAL SOCIETY N.S.W. RN j JOL a-j (see separate descriptions)—Ref. Table 1. Plate I1—Development of the bud in histological section. BUD FAILURE OF STONE FRUITS Matcoirm, H. D. R., 1965. The Golden Queen Peach. Agric. Gaz. N.S.W., 76 (3), 143. Matcoim, H. D. R., 1970. On the Physiology of the Shoot System of Peach with Special Reference to Bud Failure. Ph.D. thesis. Macquarie Univesrtiy. Matcoum, H. D. R., 1972. Some Growth Substances Associated with Bud Failure of Peach. In :— Plant Growth Substances 1970. D. J. Carr (Ed.), Proc. 7th Intl. Conf. Springer-Verlag, Berlin. Mancy, K. H., and WestGartH, W. C., 1962. A Galvanic Cell Oxygen Analyzer. Journ. W.P.C.F., 34 (10), 1037, Asheville, Carolina, U.S.A. Moore, S., and Stein, W. H., 1948. Photometric Ninhydrin Method for Use in the Chromatography of Amino Acids. J. Biol. Chem., 176, 367. MurneEEk, A. E., 1930. Quantitative Distribution and Seasonal Fluctuations of Nitrogen in Apple Trees. Proc. Amer. Soc. Hort. Sci. 27, 228. Oser, B. L. (Ed.), 1965. Hawk’s Physiological Chemisiry. 14th Edn. McGraw-Hill, New York. Rabu, I. F., 1960. Translation. :—Changes in Total Nitrogen During the Vegetative and Dormant N.S.W. Dept. of Agriculture, Biological and Chemical Research Institute, P.M.B. 10, Rydalmere, N.S.W. 2116. Australia. 201 Periods of Apple, Pear, Apricot and Peach Trees. Lucr. sti. Inst. Cerc. Hort-vitic., 1959-60, 1961. Rocers, L. J., 1965. A Simple Apparatus for Disc Electrophoresis. Biochem. Biophys. Acta., 94, 324. SaIkiA, B. N., Kester, D. E., and BrapLey, M. V., 1967. Dormant Vegetative Buds in Normal and Bud-failure Forms of Almond. (Prunus amygdalus Batsch). Proc. Amer. Soc. Hort. Sci., 89, 150. SmitH, I. (Ed.), 1958. Chromatographic and Electrophoretic Techniques. William Heinemann. Medical Books Ltd., London. STADLER, J. D., and Strypom, D. K., 1967. Flower Bud Development of Two Peach Cultivars in Relation to their Winter Chilling Requirements. Sth. Afric. Journ. Agric. Sci., 10 (3), 831. TayLor, B. K., 1967. Storage and Mobilization of Nitrogen in Peach Trees: A Review. J. Aust. Inst. Agric. Sci., 33 (1), 23. TREVELYAN, W. E., Proctor, D. P., and HARRISON, G. S., 1950. Detection of Sugars on Paper Chromatograms. WNatuve., London, 166, 44. WEINBERGER, J. H., 1967. Studies on Flower Bud Drop in Peaches. Proc. Amer. Soc. Hort. Sci., 91, 78. (Received 3.2.75) 202 (a) A “single ”’ flower bud from which the outer glabrous scales have been removed to show the hairy inner scales (a) Longitudinal section through the bud primordia in the axil of a leaf on the KE cultivar in late October, 1966. H. D. R. MALCOLM Mu EXPLANATION OF PLATE I (hs) and abscission zone (az). (Approx. 3x natural size). (b) A typical necrotic “ single’ flower bud fro which the scales have been removed. (Approx. 3x natural size). (c) Lateral shoots bearing flower buds below which an abnormal abscission zone (az) has formed into the cortex of the shoot. This abscission causes loss of the whole triplet bud (tb). (Approx. natural size). Photograph courtesy of Dr. P. F. Kable. — (d) A “ triplet ’’ bud formation in the axil of a mature leaf. Note the relatively small vegetative bud situated — between the two flower buds. (Approx. natural size). (e) Necrotic flower buds in the “ triplet’’ bud 7 formation causing early growth of the central vegetative bud. (Approx. 4 natural size). j I-XPLANATION OF PLATE II The central vegetative bud (vb) can be seen to the right of the photograph, with the primordium of the © reproductive bud (rb) to its left, the two being covered by the prophyll (pr) shown on the far left. Note the © oxalate crystals (ox) in the cells of the prophyll. Magnification x55. (b) A KE reproductive bud primordium ~ in late November. Note the bud-enclosing prophyll (pr) on the right of the photograph. Magnification x55. © (c) A KE reproductive bud primordium in early January, 1967. Magnification x55. (d) A KE reproductive bud in early February, 1967, with all but two of the scale initials (sc) removed. Note the characteristic © dome shape of the tunica (ta) indicating onset of differentiation. Magnification x55. (e) A KE reproductive bud in late March, 1967. Calyx lobes (cl) have begun to appear around the periphery of the now “ flattened” | tunica (ta). Magnification «20. (f) A longitudinal section through a differentiating KE reproductive bud | in late April, 1967. Note that within one month, the corolla (co), androecium (ad) and gynoecium (gc), have © differentiated. Magnification «55. (g) A longitudinal section through a KE reproductive bud in early May, 1967. Note the increase in bud size, the enlarged gynoecium (gc) with its elongated style (st) and the © androecium differentiating into filaments (fl) and anthers (an). Magnification x55. (h) A KE bud section | li in early June, 1967. Note that little differentiation of the flower initials has occurred during the past month. |} |) Magnification x20. (i) A KE bud section in early July, 1967. In the past month rapid differentiation of — hu the flower initials has taken place, and the bud has increased in size. Tetrads of spores (sp) have differentiated D in the anthers, and two ovules (ov) have differentiated in the ovary. The style has also further elongated. |§ , Magnification x20. (j) A KE bud section on July 19, 1967. The bud has enlarged considerably on approach | of bud burst. Pollen (po) has formed in the anthers and filaments have formed (broken away in the sectioning). | A single ovule is shown in the ovary, the other having degenerated. The bud differentiation is now complete. Magnification x 8. 1960 of th ite ty dive at 203 Report of Council for the Year Ended 31st March, 1975 Meetings and Lectures : LOCATION : Large Hall, Science House, 157 Gloucester Street, Sydney: April 4th: Annual General Meeting, Presidential Address : Floppy Rulers and Light Pens, Dr. J. P. Pollard, Australian Atomic Energy Commission. May Ist: Some Little Publicised Aspects of the Design of the Sydney Opera House, Mr. Peter Hall, Architect. June 5th: Basic Drawings for Fine Art, Industry and Social Communication, My. Arthur J. Murch, Artist. July 3rd: Adaptations of Cattle to Tropical Environ- ments, Professor N. T. M. Yeates, Professor of Livestock Production, University of New England. August 7th : Conservation of Marine Resources, Dr. K. Radway Allen, Chief, Division of Fisheries and Oceanography, CSIRO. September 4: Symposium, Students’ Attitudes in Contemporary Educational Institutions, Prof. A. G. Mitchell, Macquarie University; Mr. B. Coles, President, Sydney University Union ; Mrs. B. Bowen, Principal, Killava High School. October 2 : The Formation of Petroleum, Dr. J. Taylor, Assistant Chief, CSIRO Division of Mineralogy. November 6: Food Additives, Mr. John Neuhaus, Assistant Government Analyst, Division of Analytical Laboratories, Lidcombe. December 4: Designing a New-Generation Aircraft Landing System, Mr. H. C. Minnett, Chief, Division of Radiophysics, CSIRO. LOCATION : Lecture Theatre 2, School of Chemistry, University of Sydney: August 15: Liversidge Lecture for 1974—Chance and Design: An Historical Perspective of the Chemistry of Oral Contraceptives, Professor A. J. Birch, Dept. of Ovganical Chemistry, Research School of Chemistry, Australian National University. Attendances at these meetings totalled 519. Annual Dinner: The Annual Dinner, held in the Reception Hall, Sydney Opera House, was attended by 93 members and guests. The guest speaker was Prof. B. R. Williams, Vice-Chancellor and Principal of the University of Sydney, his address being entitled, * Science, Wisdom and the Good Society.” Awards.—The following Awards for 1974 were made : James Cook Medal: Sir Marcus Oliphant ; The Edge- worth David Medal: Dr. A. W. Snyder ; Clarke Medal : Dr. C. H. Tyndale-Biscoe; Walter Burfitt Prize: Dr. B. Robinson; Olle Prize: Mr. David A. Gray ; = Bevo ides Research Lectureship: Prof. A. J. irch. The Society’s Medal was not awarded. Summer Schools——Two highly successful Summer Schools, held during January 1975, were attended by more than 120 Fifth Form students. The one organized around the theme “‘ Chemistry and the Consumer ”’ was held at Macquarie University, the other entitled ‘‘ The Earth’s Environment in the Universe’’, was held at Science House and included visits to CSIRO Radio- physics Laboratories, Epping, the University of Sydney, Fleurs Observatory at Kemps Creek and Sydney Observatory. Membership.—Membership at 3lst March, 1975, was—Life Members 10, Members 374, Associates 30. Publications —Volume 107 of the Journal and Proceedings was published in two parts during the year. A grant of $500 was received from the National Library of Australia towards the cost of publishing a subject index. This index was prepared by Mr. A. F. Day and covers the four years of the Transactions of the Philosophical Society of New South Wales as well as the first fifty years of the Journal and Proceedings of The Royal Society of New South Wales. Library.—2,690 items were received and processed. These comprised periodicals on exchange from some 354 societies and institutions, donations and periodicals purchased. Two hundred and fifty-nine members, societies and organizations used the library facilities during the year. The re-cataloguing of the library was commenced during the year. Finance.—Due to increasing costs and loss of revenue from Science House, the year has been a most difficult one financially, the deficit for the year being $10,742. Council does not expect any improvement until after the new Science House is well established. A grant of $1,750 was received from the Government of New South Wales. Originally this was made in lieu of printing the Journal but now falls far short of this expenditure, which currently is approaching $8,000 a year. New Science House.—During the year Science House Pty. Ltd., the company jointly formed by the Society and the Linnean Society of New South Wales purchased a building at the northern end of Clarence Street for the purpose of establishing a Science Centre to replace the existing Science House. Alterations to the building are expected to begin during the first half of the coming year. Acknowledgements.—Council wishes to acknowledge the excellent work carried out during the year by the Executive Secretary, Mrs. V. Lyle, the Assistant Librarian, Mrs. G. Proctor, and all concerned with the organization of the Summer Schools and monthly lectures. Honorary Treasurer’s Report There was a deficit for the period of $10,742 as against a deficit for the previous year of $5,293 resulting in a net additional deficit of $5,449 made up as follows : $ $ Increase in general interest .. 2,538 Increase in sale of back numbers 1,905 Increase in members subscriptions . . and application fees 547 Increase in donations received : 483 Increase in summer school surplus . . 91 Sale of centenary volume and subject index : #4 ws 144 Reduction in rentals . 1,348 7,056 Less $ Reduction in science house surplus .. 3,370 Reduction in sale of reprints eau nig eet Reduction in subscriptions to journal 469 Reduction in sale “Sydney Opera House Commemorative Issue ”’ 1,153 Increase in salary costs 2,561 Increase in printing costs 3,295 Increase in general expenses 272 Library recataloguing 1,058 12,505 Total decline $5,449 Report of the South Coast Branch of the Royal Society of New South Wales Officers : President : B. Clancy Secretary : G. Doherty Council representative : G. Doherty No meetings of the South Coast Branch were held during the year. Report of New England Branch of the Royal Society of New South Wales for 1974 Officers foy 1974 Chairman H. G. Royle Secretary-Treasurer T. O’Shea Committee R. L. Stanton N. 0; M. Yeates D. H. Fayle N. i Fletcher Branch Representative on Council R. L. Stanton The following meetings were held : 3rd May, 1974: The Nature and Significance of Fossil Evidence Concerning the Separation of the Continents During Geological Time, Professor D. Hill, F.R.S. Emeritus Professor of Geology, Univ- ersity of Queensland. 20th September, 1974: The Ecology of Worm Populations, Dry. J. W. Pickett, Geological Survey of N.S.W. President, Royal Society of N.S.W. 15th October, 1974: Alcohol and the Breathalyser, Dr. P. Carroll, University of New South Wales. Last financial year an amount of $28,420 was set aside to be written off over a three year period with the present year being the second year of this budget plan. The reason for this approach is that the loss of income from Science House was thereby to be made available for general operating expenses of the Society. The present deficit includes a heavy component resulting from the nearly doubling of our printing expenses for the Journal, although this was fortunately offset by the sale of back issues—a “ windfall” item which cannot be anticipated in our coming budget. We enter the third year of our budget plan with $12,385 available (15% more than the current year). However, by the end of the three year period, cash flow is not expected from Science House Pty. Ltd. as was anticipated. The management of our remaining cash reserves in the present inflationary climate, t becomes a critical task for the Council in the coming years and some cutting back in expenses seems inevitable as our reserves would otherwise only take us to 1977. | < t Z , Mi 21st November, 1974: Man’s Future in the Light of — His Past Evolution, Professor G. Ledyard Slebbinaae University of California. felel. 7 lelores [21 2. Financial Statement, 1974 : Previous Balance $118.13 Accumulated interest $4.15 Present Balance $122.28 (Zig les |212 G. DOHERTY, 3lst March, 1975. Secretary. WEFleloe Financial Statement : Balance at Commercial Banking Company of Sydney Limited, University of New England Branch, 29th March, 1974 .. $273.34 Credit—Interest to 25th June, 1974 $4.96 Interest to 30th December, rs 1974 ; $4.82 > —_—_—_. $283.12 | Debit—Advertising $7.00 5. $7.00 7 Balance at 3lst March, 1975 : $276.12 — Rop GOouLp, - 31st March, 1975. Secretary-Treasurer. 205 EXPENDITURE ACCOUNT FOR YEAR THE ROYAL SOCIETY OF NEW SOUTH WALES DED 28TH FESRUARY 1975 BALANCE SHEET - 287TH FEBRUARY 1975 wid e : yea RESERVES 15a 2 wl 12,123 Library reserve - note 1 10,478 % $ 453,971 Resumption reserve 453,971 (5,041) NET SURPLUS (DEFICIT) for period before bad debts (10,953) td. a 205 LIBRARY FUND - note 1 5,214 Add . — LONG SERVICE LEAVE FUND - note 1 eos -- REDUCTION in provision for bad debts 641 aun 26,695 ACCUMULATED FUNDS 16,793 aa eae 5,041 10,312 Mae 492 ,995 NET FUNDS $487,262 (5,044) i ciate) if — ed 23 ont peoracsicen. oy) 175 INCREASE in provision for bad debts a2 y eh SCRIPT IONS itt FF 4 seid 675 Cash at bank and in hand 6,a04 SUBSCRI written off es ai 205 Cash at bank - library fund. - note 1 214 252 ree — Debtors for subscriptions ~ note 2 — es2 Other current debtors and prepayments 1,394 5,293 NET SUI (CEFICIT) F 20,318 Burt tarn deposits 7350 (5,293) D PLUS (CEFICIT) for period (10,742) 2,050 15,202 Ada Less — DONATIONS to libravy fund 5,009 CURRENT LIABILITIES 17, 162 INTEREST on compensation investment _ 674 Sundry creditors & accruals 6,316 = TRANSFER from library reserve — note 1 1,645 128 Subscriptions paid in advance 366 37,37 ACCUMULATED FUNDS brought forward from 1974 26 696 6 Life members subscriptions - current portion 6 49,25 FUNDS AVAILABLE 22,608 608 6,688 31,282 NET CURRENT ASSETS 8,544 Less * Add = TRANSFER to library fund - note 1 5,009 FIXED ASSETS - note 4 17, 162 TRANSFER to resumption reserve -_ 1,858 Furniture and office equipment 2,208 3,224 TRANSFER to library reserve aa 2 Lantern 2 — TRANSFER to long service leave fund — note 1 605 13,600 Library 13,600 2,154 CENTENARY VOLUVE — stock written off _ 16 Pictures 15 " £5) thay PE SeLINOE RS rsfrte ” Ae : Peg ee rity t: sete a Ct eapa els ety re pg he er ‘ bein) eeriys P 7 . hata’s 12h ea , - Uy be we F Sept dente eR ie pe te bd eS i Pedi icor OL un ia Peers se) ty raat aires :’ ; PA, es q id dee Teas 2 ‘ oes x Ae Rs x ' Doar UN Ciena Manne toe reprbiresy . * Sas vena Coreres as bhot oh By Mont re ‘ “ “ “ . tie Sterner te one ‘ . : i ar i . : CSS St ean , 7 : ‘ WGP? 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