Structure and Relationships of some Middle Devonian Plants from Western New York
1940; Wiley; Volume: 27; Issue: 2 Linguagem: Inglês
10.2307/2436686
ISSN1537-2197
Autores Tópico(s)Plant Parasitism and Resistance
ResumoTHE PLANT remains described here are some addi- (1938) ; Iieimannia aldenense Arnold (1935) ; Schitions to a very interesting flora present in two hori-zopodium M ummii Read (1938) ; I ridopteris erienzons in the Hamilton group of western New York.sis Arnold gen.et sp.nov.; Xenocladia medullosina The uppermost of the plant-yielding beds is the Arnold gen.et sp.nov.Tully pyrite, which is so named because it was for-Of the genera in the above list, only two, Schizomerly considered equivalent to the Tully limestone podium and Aneurophyton, were originally describwhich prominently marks the base of the Upper De-ed from elsewhere.Reimannia was first described vonian in the central part of the state.The limestone from the Ludlowville shale at Alden, but has since itself does not extend into western New York, and been recognized in the New Albany shale in Kenrecent stratigraphical work indicates that the pyrite tucky (Read and Campbell, 1939).The remaining bed instead of being a westward extension of the genera, Arachnoxylon, Iridopteris, and Xenocladia, limestone horizon, as was once believed, belongs to are known only from western New York.the upper part of the Middle Devonian (Hamilton).1\11'.Irving G. Reimann, of the Buffalo Museum Although the name "Tully pyrite" is retained as a of Science, is mainly responsible for the collections convenient designation, age identity with the Tully of plant-bearing nodules from the Ludlowville shale limestone is no longer implied.The other plant-at Spring Creek, and Mr. Max J. Kopf, of Lancasbearing horizon is lower and is contained within the tel', New York, supplied most of the material from Ledyard member of the Ludlowville shale.It is sepa-the Tully pyrite.rated from the Tully pyrite by the Moscow shale Iridopteris eriensis gen.et sp.nov.(fig.1,5).and the Tichenor limestone which together have a The name Iridopteris eriensis is proposed for a well thickness of about fifty feet.preserved axis from the Tully pyrite.The structureThe plants from both horizons are pyritized and measures about 4 X 5 mm. in cross section, and the show cell structure, but microscopic examination is shape of the xylem strand is distinctive.The strand possible only with reflected light.In the Tully py-is a solid mass of tissue of five "arms" centrally rite the plants occur as wood and stem fragments united but so arranged that four are in opposing scattered sparingly among the invertebrate fossils pairs, with the fifth one occupying a median posithat make up the bulk of the lenticular pyritic tion to one side (fig.1).The configuration reminds masses.Although preservation of the tissues is often one of the fleur de lis, which in turn suggests the good, the preserved parts are small and consist most-name I ridopteris.No marked changes have been obly of slivers resulting from the disintegration of served in the xylem at different levels, although the larger pieces of wood.All the plant remains de-structure has not been followed for a length of more scribed in the present paper were collected in than two centimeters.It is possible that the entire Erie County where they are abundantly distributed section comes within the limits of a single internode.throughout the Tully pyrite.Read (1938) also re-N ear the extremity of each" arm" are one or two ports their occurrence at the same level in Ontario small parenchyma filled spaces (fig.5), the so-County.In the Ludlowville shale in Erie County the called "peripheral loops."These evidently mark the plants occur in small marcasite nodules embedded in position of the protoxylem and suggest relationship the gray shale, and the most prolific locality is in the with certain Paleozoic ferns as the Cladoxylaceae bed of Spring Creek just east of the village of or the Zygopteridaceae.Passing off laterally from Alden.These nodules contain a variety of inverte-the extremities of these "arms" are small traces (fig.brate remains as well as plants.5 at A) which apparently supply rachial pinnules Although Dawson (1862) included brief descrip-borne directly upon the main axis between the larger tions of structurally preserved plants from western divisions.These have not been followed beyond the New York in his inclusive studies of the Devonian point of departure from the main xylem strand.Lyplants of eastern North America, no systematic at-ing directly opposite the ends of the xylem "arms" tempts have been made to resume the study of them are rather large bundles which apparently constitute until recently.In 1935 the present author described the traces of the pinnae or whatever type of structwo new species from Erie County, and in 1938 Read ture sprang from the axis.Five of these lying oppodescribed additional material from the Tully pyrite site the xylem "arms" and in various stages of deat Canandaigua Lake in Ontario County.Altogether parture may be observed in a single well preserved six structurally preserved forms are now known cross section.Three traces are indicated in figure 5 from the Hamilton group.These may be listed as at B, C, and D. (The remaining two are shown in follows: Anellrophyton Hallii (Dawson) Arnold outline but are not lettered.)These larger traces comb.nov.; Arachmoxulon.Kopji (Arnold) Read appear to be given off in spiral sequence.Some of 1
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