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perhaps, be interesting to offer a few short remarks respecting them, under the following divisions: —
1. Their numerical proportion and zoological cha
2. Their local distribution.
3. Their comparison with other species from the Pa
laeozoic system of Europe and America.
4. To estimate the position that the deposit containing
them occupies in the geologic series.
The numerical proportion of the organic remains, as far at least as they appear to be known at present, are about 48, — a very small proportion, indeed, as compared with the European Palaeozoic fauna. Of these, 10 belong to Polyparia, 14 to Conchifera, 12 to Brachiopoda, 7 to Gasteropoda, 1 to Heteropoda, 2 to Pteropoda, and 2 to Crustacea; and also some remains of fishes.
These are variously distributed: thus, in the Illawara district, New South Wales, the preponderance of the bivalve Mollusca, Pachydomus, &c, and numerous individuals of the gasteropodous genera, as Pleurotomaria, Platyschisma, &c, with here and there a Brachiopod, and some traces of Polyparia (Stenopora crinita, Lonsdale), lead us to infer that the chemical and mechanical conditions were favourable to their developement, and that the deposits containing them may have been littoral, or accumulated at no great distance from the ancient shore. On the other hand, the coarse sand-rock of Raymond Terrace appears to have been rather unfavourable to the existence of the Testacea, not any of the Conchifera or Gasteropoda previously -mentioned being there to be found; fragments of Polyparia, similar to those in Aran Diemen's Land, a Conularia, and two or three species of Brachiopoda, being but sparingly distributed, owing their position, probably, to the drifting by tidal currents. The Booral deposit is interesting, as leading to a different state of things: it is a dark flaggy rock, or bituminous limestone, containing none of the principal genera above noticed; but numerous remains of species referred to Littorina and Turritella, with fragments of Icthyodorulites, and abundant traces of the minute crustaceous genera Bairdia and Cythere, the latter forming regular layers in the limestone, just as they are found deposited in the carboniferous shales near Halifax in Yorkshire and other parts of England, and Ireland.
In Van Diemen's Land, where, as previously adverted to, the strata are extremely variable, the chief fossiliferous deposit appears to be Mount Wellington and some adjacent localities: in these we find the different species of Brachiopoda attaining a much greater numerical developement than in the corresponding series on the Australian continent; the Productus Brachythcerus, Spirifer avicula, S. vespertilio, and other species, are extremely abundant, some of them being of considerable size. Associated with these are numerous traces of fine and large specimens (and in some places filling the rock in every direction) of the different species of Polyparia, as Stenopora ovata and Tasmaniensis, Fenestella ampla, F. internata, and F. fossida, &c.; while the remains of Conchifera and Gasteropoda are but rarely to be discovered; the locality at Spring Hill containing the largest proportion, with one species of Polyparia, the Stenopora informis (Lonsdale).
I n comparing these forms with those from the Palaeozoic series of other countries, we find some of them to be identical, and others to be representative species: the Terebratula hastata is the same as the English species; a Spirifer near to S. glaber ( Mart.); the Littorina Jilosa, very closely allied to, if not identical with, Loxonema sulcatida (M'Coy); and the Turritella tricincta, near to T. acicula (Phillips). Of representative forms, we have the Spirifer crebristria, allied to S. glabristria (Phil.); and Athyris depressa (M'Coy); the Sp. Tasmaniensis, to the S.Pentlandi (D'Orb), from the carboniferous limestone of Bolivia ; and the Sp. Stokesii, near to a Kendal species. Of the winged Spirifers, the S. avicula and S. vespertilio belong to the group of S. convoluta (Phil.), and S. externa (Sow.) ; and a variety of the S. vespertilio is very near to the »S'. condor (D'Orb), from the carboniferous deposit of Bolivia; and another to the S.Lyellii (DeVerneuil). The Australian Productce are allied to the English forms of that genus. Of the Polyparia, the Fenestella generally appear to be the representatives of some English and Irish species.
Having thus briefly alluded to the local distribution and general resemblances of the Australian Palaeozoic fauna, it is important to remark the absence of certain genera (so far at least as our observations on different collections have extended), which are abundantly distributed in the equivalent deposits of northern Europe. Of the family Cephalopoda, no traces of the Nautilus, Clymenia, or Goniatites have hitherto been detected; nor have there been found any remains of the true Leptamw, or scarcely of Orthida; (one doubtful fragment from Booral excepted), genera, so characteristic of the Devonian and carboniferous strata of other countries. Trilobites appear to have been equally rare; and the Crustacean family is represented by two or three species belonging to Cypridiform genera. On the other hand, the presence of a species of Bcllerophon and Conidaria, seven or eight of Spirifer, and two or three belonging to the gibbosc species of Productus, — the latter being forms generally found in the carboniferous limestone,—and these associated with carboniferous types of Polyparia and a few allied forms of Concliifera and Gasteropoda, —lead us to believe that the deposits containing them may probably belong to that division of the Palaeozoic series usually termed carboniferous.
The above observations apply chiefly to the great mass of ancient fossiliferous strata of these countries; but it also appears, from the evidence of superposition brought forth in the Geological Section, as well as by the fossil organisms contained therein, that the deposits at Yass Plains and Shoalhaven, in New South Wales, are anterior to the other strata, and may probably be considered the equivalent of the Devonian system of Europe. The fossil species from these deposits are but imperfectly known: Favosites Gothlandica, another species of Favosites, and Amplexus arundinaceus (Lonsdale), fragments of Orthoceras and remains of Trilobites, have only at present been noticed. Thus, the Palceozoic series of Australia and Tasmania may be regarded as partly the equivalent of the Devonian and carboniferous system of other countries.
I cannot conclude these brief notes without remarking that many forms in these deposits may have been obliterated; and others so considerably altered, that it is rather difficult to institute careful comparisons, from the rnetamorphic action that has been induced on many of the strata by the intrusion of trappean dikes, and which appear to have been more frequent in Van Diemen's Land than in the corresponding series on the Australian continent.
Mollusca (described by Mr. G. B. Sowerby).
Testa ovato-ventricosa, crassiuscula, laevi, polita, antice posticeque rostrata; rostri antici longioris tuberculis duobus dorsalibus; rostro postico leviter reflexo; spirae anfractibus duobus conspicuis; apertura elongata, angusta, sinuosa, ad utramque extremitatem canalifera, canali postico ascendente; labii externi margine interno dentato, dentibus posticis minoribus, anticis prope canalem subinconspicuis, interruptis; labii interni margine interno sulcis angustis transversis, interstitiis crassioribus, anticis longioribus; lateribus basalibus prope extremitates crassis, dorso versum marginatis.
A fossil Cowry, of a very remarkable form, bearing but a very slight resemblance to any of the hitherto known species, either recent or fossil. In general form it slightly resembles Cyprcea Scottii: it may, however, be readily distinguished from that species by its lengthened anterior and posterior canals, by the two tubercles on the posterior dorsal part of the anterior canal, and by the very remarkable grooves or ribs of the inner edge of the inner lip. It was found in a muddy sand, in sinking a well to 140 feet in depth, at Franklin's Village, Van Diemen's Land, about fifteen miles from the sea.
Terehratula compta. (PI. XIX. fig. 4.)
Testa laevis, tenuis, trapeziformis, marginibus lateralibus subincurvis, antico parvo obtuso, area cardinali magna, linea depressa longitudinali ad utrumquc latus; valva, ventrali rotundato-trigonula, planulata, antice subtruncata, depressione mediana parva; valva, dorsali longitudinaliter obtusissime carinata; apertura bgamenti adhesionis parva, terminali, circulari.
Locality—Port Fairy, New Holland, associated with casts of Nucula, Lucina, and some other species of Testacea, in an elevated beach.