^, \S IMAGE EVALUATION TEST TARGET (MT-3) // A •J / ^ ^0 1.0 I.I 12.8 tio 2.5 2.2 £ b£ 12.0 I' I m 1.25 |,.4 |,.6 ^ 6" ► 0% <^ '^. /: *>: / O^, /A Photographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. MSSO (716; 872-4$03 ;{V ^^ <^ ^^ \ \ cs^ ^^^-. "^^ ^.■«>' '«V CIHM/ICMH Microfiche Series. CIHM/ICMH Collection de microfiches. Canadian Institute for Historical Microreproductions / Institut Canadian da microreproductions historiquas 1 ^mm Tschnical and Bibliographic Notaa/Notas tachniquaa at bibliographiquaa Tha Inatituta haa anamptad to obtain tho baat original copy avaiiabia for filming. Faaturaa of thia copy which may ba bibliographieally uniqua. which may altar any of tha imagaa In tha raproduction, or which may significantly changa tha uaual mathod of filming, ara chackad balow. D D D D D Colourad eovara/ Couvarturo da coulaur I I Covan damagad/ Couvartura andommagte Covars raatorad and/or laminatad/ Couvartura raataurAa at/ou palliculAa □ Covar titia missing/ La titra da couvartura manqua □ Colourad mapa/ Cartaa gAographiquaa an coulaur □ Colourad ink (i.a. othar than blua or black)/ Encra da coulaur li.a. autra qua blaua ou noira) I I Colourad plataa and/or iiluatrations/ Planchaa at/ou lllustrationa an coulaur Bound with othar matarial/ RalM avac d'autraa doeumants Tight binding may cauaa shadows or distortion along intarior margin/ La r« liura sarrte paut causar da Tombra ou da la diatorsion l« long da la marga intiriauro Blank laavas addad during rastoration may appaar within tha taxt. Whanavar possibla. thasa hava baan omittad from filming/ II sa paut qua eartainaa pagaa blanchas aioutAoa lors d'una raatauration apparaissam dans la taxta. mala, lorsqua cala Atait poasibla. caa pagaa n'ont paa *tA film^as. L'Inatitut a microfilm* la maillaur axamplaira qu'il lui a itt poasibla da sa procurar. Las details da cat axamplaira qui sont paut-Atra uniquas du point da vua bibiiographiqua. qui pauvant modifiar una imaga raproduita. ou qui pauvant axigar una modification dana la mtthoda normala da filmaga sont indiquAa ci-daasous. r~~| Colourad pagaa/ Pagaa da coulaur Pagaa damagad/ Pagaa andommagias Pagaa raatorad and/oi Pagaa raataurias at/ou pallicultes Pagaa discolourad. stainad or foxa« Pagaa dteolortes. tachatias ou piquAaa Pagaa datachad/ Pagaa ditachtes Showthrough/ Transparanca Quality of prin Qualit* inigaia da I'imprassion Includas supplamantary matarii Comprand du material supplimantaira Only adition avaiiabia/ Saula Mition disponibia r~~| Pagaa damagad/ pn Pagaa raatorad and/or laminatad/ r~~| Pagaa discolourad. stainad or foxad/ I I Pagaa datachad/ r~~| Showthrough/ |~n Quality of print variaa/ r~~| Includas supplamantary matarial/ r~~1 Only adition avaiiabia/ D Pagaa wholly or partially obscurad by errata slips, tissuas. etc.. hava baan rafilmed to ansura tha bast possibla imaga/ Laa pagaa totalamant ou partiallamant obscurcias par un fauillat d'arrata. una palure. ate. ont M filmias A nouvaau da facon A obtanir la maillaura imaga possibla. Additional commanta:/ Commantairas supplAmantairas; Pasimtion ii at foltowt : [103] - 109 p. This itam is filmad at tha raduction ratio chackad balow/ Ca document ast film* au taux da rMuction indiqu* ci-dassous. 10X 14X 1SX 22X 26X 30X u J 12X 16X aox 24X 28X 32X Th« copy film«d h*r* ha* b««n raproducsd thanks to tho g«n«ro«ity of: TtM Nora Sootia UgMitfra Library L'oxomplaira filmA fut raprodult grioo i la g«n«ro«it« do: The Now Sootia Lt|iiloti»t Library Tho imagoo appoaring horo aro tho boat quality pooaiblo conaidoring tho condition and laglblHty of tho original copy aiHJ in kaoping with tha filming contract spocif Ications. Laa Imagaa sulvantao ont «t4 roproduhoa avac la plua grand aoin. compto tonu do la eondltion ot do la nattat* da I'axamplaira film*, ot an conformKi avac las conditions du eontrat do filmaga. Original copios in printed papor covors ara fllmod boginning with tho front covor and anding on tho laat pago with a printad or illustratad impraa- ston, or tho back covor whon appropriata. All othor original copios ara fllmad beginning on tha first paga with a printad or illustratad impras- sion. and anding on tt«o last paga with a printad or illustratad imprassion. Laa axamplairaa orlginaux dont la couvortura an papiar aat imprim^o sont fllmis on eommon^ant par la promlor plat ot on tarmlnant soh par la damMra paga qui comporto uno omprainta d'impraaaion ou dINuatration. soit par la aaeond plat, salon lo cas. Tous los autraa axamplairaa orlginaux sont filmte on cominonpant par la pramlAra paga qui comporto uno omprointo d'improsslon ou d'lllustration ot on torminant par la domMro paga qui comporto uno tollo omprointo. Tha last rocordod frama on oach microflcho shall contain tha symbol — »• (moaning "CON- TINUED"), or tha symbol ▼ (moaning "END"), whichaver applias. Un das symbolos suivants apparattra sur la darniiro imaga da chaquo microflcho. solon lo cas: la symbolo — »• signHIo "A 8UIVRE '. lo symbolo V signlflo "FIN". Maps, plates, charts, etc., may be filmed at different reduction ratios. Those too large to be entirely included in one exposure are filmed beginning In the upper left hand corner, left to right and top to bottom, as many frames as required. The following diagrams illustrate tho method: Los cartes, planches, tableaux, etc., pauvont Atra filmto A das taux do rMuctton diff«ronts. Lorsque lo document est trop grand pour Atro roproduit on un soul cllch*, II est film* i partir da Tangle sup4rlaur gauche, do gauche i droito. ot do haut en baa. en prenant lo nombre d'images n4cossalre. Lee diagrammea suivants illustrent la mithode. 1 2 3 1 2 3 4 5 6 SmL^^^^ feac^-''-rir3i; j6rj i - wa:-:y"'' T^'aa^TL"??: o a i • iC"-'-. -r* ;««L-^ y y - [/•/•0//I the QrARTF,RT,Y Journal of the Geological Societt /or Ma;/ 1882.] NoTRs o/i PRoroTAXiTEfl uii'l I'AcnrxHECA iHscoiiered hy Dr. Hicks )/i the Denbiohshire Urits 0/ Corwen, N. Wales. By Prin- cipal Dawson, LL.D.. F.R.S., &c., M'Gill College, Montreal. Specimens of the tirst-mentioned fossil were kindly sent to me by Dr. Hicks, at mv recjucst, but unfortunately arrived when 1 waa at my summer residence at Little Metis. Though without the means of" examining them microscopically, I ventured to write, after studying them with a good pocket-lens, that they resembled Pn)- tnta.vUen, and could not be referred to Algic. The latter conclu- sion might appear rash ; but there are, to the practised eye, indi- cations in sjiocimens of this kiud which can scarcely deceive. The fibrous and highly carbonaceous nature of the darker Bi)eci- mvns, and the silky and incoherent texture of the lighter-coloured ones, are characters never found in any fossil plants except those liaviiig durable woodv tissues. Further, the occurrence of the material in angular fragments and in a condition approaching to that of the mineral charcoal of the Coal-measures, proves subaerial decay, little likely to have occurred in the case of aiiuatic plants. From'thc state of preservation of the specimens, 1 also inferred that, if really of the nature of Protntaxltes, they might throw some addi- tional liglit on its structure, as the specimens previously studied had been from entire trunks in a silicified state. On my return to town, I found awaiting me the Journal of tho Geological Society containing Dr. Hicks's paper ; and the figures there given showed nt once the correctness of the reference made by Mr. Etheridge of the ]dant io Prototaxites, and its close resemblance to P. L'K/am*, except in the appearance of bifurcating fibres, a cha- racter which I have not observed, and which may be merely an error in observation or in drawing. Portions of the specimens sent by Dr. Hicks were at once pre- pared, not only by slicing but by treatment with boiling nitric acid, and by diffusion ' of the more lax fibres in water and in Canada baham. ( )n examination they gave the results stated below. In state of preservation tlie two kinds of specimens examined are somewhat different. The dark variety has the long cells or woody fibres filled with rods of transparent siliceous matter, and the walls are represented by a thick structureless layer of carbon, which often shows angular cracks such as appear in the waBs of thick-walkd woody fibres when carbonized. These cracks are some- times transverse, giving a scalariform appearance, but they do not represent a true structure. The internal sUiceous casta, when bared by nitric acid of their carbonaceous coating, show here and there transverse or spiral markings, produced by the projection of the ligneous lining on the inner side of the cells. There is no trace ot * Report on Pcvor.iaii Plants of CnnndH, 1871. pi. ii. ^JSe^ 104 PKINCIPAL DAWSON ON PROTOTAXITKS AND the intercellular flocculcnt matter produced bj' decay of the outer surfaces of the cells or their connecting tissue, such as I have described in the silicified trunks of I'rototaa-itis. The lighter-coloured variety has probably been originally preser- ved in a similar manner ; but the -woody envelope of the fibres has been entirely removed, leaving only the siliceous internal casts, which are so' lax that they can be scraped into water and viewed as transparent objects without sHcing. This is precisely the state of the asbestos-like silicified Coniferous wood found in the gold gravels of California. These rod-like siliceous casts preserve on their sur- faces distinct traces of the irregularly spiral ligneous lining of the perished cell-wall. A few of them also show rounded bodies of brownish colour in their interior. These may be ferruginous con- cretions, but arc possibly granules of resinous matter, in which case such tubes may represent resin-cells. In all the above particulars these specimens confirm my original determination of the woody character oil'rototcurites, to which genus they undoubtedly belong. They differ, however, from J'. Lorjnnim the smaller diameter of the fibres, and in the ligneous lining, which presents the appearance of interrupted transverse bands rather than regular spirals. These characters would seem to indicate a distinct species, which may therefore be named P. Biclsii, in honour of its discoverer*. I may recall here a statement made in my report on the Devonian plants of Canada, that in 1870, when Mr. Etheridge •was so kind as to permit me to examine the slabs in the Jermyn- Street Museum, with Pachijtheca of Hooker from the Ludlow, I recognized, associated with this, fragments of w-ood having tho structure of Prototaxites. The similar association in Dr. Hicks's spe- cimens and the peculiar fibrous structure of the walls of Pachi/theca, as figured by Mr. Etheridge, may well excite the suspicion that these bodies aie connected with Protota.vites, especially as similar round bodies are seen in beds holding this fossil in Canada, though without distinct structure. In this connexion it is to be observed that the bodies in question are probably seeds rather than spore-cases, and that they have tho structure of ^iheotesta, to which, in a recent paper in the Journal of the Geological Societyt, I bave referred a similar seed, found in the Devonian of Scotland. With reference to the afiinitics of Prototaxites, I have not made the crude assertion attributed to me, that this plant " belonged to Taxinese." I merely compared its structure to the lax spiral fibre of some Taxine trees, and especially to certain Taxine woods fossilized after long immersion in water, with which we are familiar in the Tertiary formations. This was all that was intended by the name Prototaxites, except to suggest that this plant was one of the proto- typal gymnosperms of the Palaeozoic period. Further, in consequence of its upper limit in Canada being apparently the Lower Devonian, where it comes into contact with the wood of the earliest species of Dadoxylov, I have conjectured that it would be found in much older * Instead of Nemafophycns Hicksii. bs proposed by Mr. Etheridge. t Vol. xxxTii. p. 30fi, pi. xii. fig. 14. PACHTTHFXA FROM THE DENBIGHSHIRE GRITS. 105 formations*, and am therefore not surprised to find this conjecture realized by the discovery of Dr. Hicks. In the specimen si'iit to mo there appears, besides the fragments of Pn,tota.ntes and a few rounded impressions probably of l'ach;itheca, a fragment of the rhi/;oiua of lYth.^thntm and portions of epi(lcnnal tissue. The state of preservation of these bears additional testimony to the woody and durable texture of ProMaxites. Still further, in recent explorations in the IJay de Chaleur, 1 have found in the Lower Devonian silicilied trunks of I'rutoUhvites two feet and a half in diameter; and these lie in beds abounding in entire specimens of Pxihpluiton, some of them apparently in the place of their growLh, and in a formation which contains only land plants, associated in some layers with remains of Hshcs and of bivalve Crustaceans, minute Gastercpods, and Sinrurhls, the whole much resembling the coal- formation in its mineral eharader and grouping of fossils. Tho idea that Pr„totn.ritex mav have affinities with lUgaj has been sufficiently disposed of in my Jomraunication to the 'Monthly Microscopical Journal' in 1«73 : and the characters and state of preservation of Dr. Hicks's specimens fully confirm the reasoning in that paper. The large specimens recently obtained at the Bay do Chaleur also enable me'to reaffirm the existence of a dense coaly bark at the surface of these trees. Some of them show on their weathered ends evidence of remarkably regular exogenous rings, extending from the surface nearly to the centre. There may, however, have been an internal axis or medulla, diff'ercnt from the outer structure ; and this I hope to be able to ascertain by scries of slices from the centre to the circum- ference of the trunk. I have lately had a number of slices made of the large silicihed trunks found last summer near Ct-aipbellton, New Brunswick. They present appearances of a verj peculiar and interesting charaetor. In the better-preserved specimens the large cylindrical iibres are failed with rows of rounded concretions of silica, often enclosing limpid hexagonal crystals. In many cases they present the most deceptive resemblance "to the bordered' pores of coniferous wood, and iu other modes of occurrence might be mistaken for spores of some parasitic fungus. Under polarized light, however, they are seen to be merely crystalline and concretionary ; and when the fibres show their true structure, this is reticulated or spiral, as iu tho ordinary specimens of Prototaxihs. In many parts of these specimens, however, the formation of granular crystals of quartz has completely disorganized the structure. 1 have referred to concretionary appearances ot tho kind above described, in my " Koport on the Devonian Plants of Canada," as occurring in the (!asi)e specimens of Prototax-ihs; but they are coarser and less beautiful tlian iu those from Campbellton. U is possible that these appearances may throw some light on the -lobular bodies observed iu the cells of the Welsh specimens of Prutotcuites and Pack >itluva, though I cannot certainly affirm that the latter are concretionary and not structural. ♦ Report on Devonian Plants. 106 PKlNCIl'AL DAWSON ON PROTOTAXITES AND I have sent a fragment of the CampbtUton ProMit.rites to Mr. CarmtherB, and have no douht that, if Mlicerl, it will show the ])eculiar state of mineralization above described. Mr. Hicks having been .so kind as to send me a s])ecimen of the rachi/theca from Corwen. I have compared it with Mr. Ethcridge's figures and description, and with similar objects from this country and elsewhere. Mr. Ktheridge's figures very accurately represent the specimen examined by me; l)ut I would make the following additional remarks. The specimen is globular, but slightly flattened in the plane of the bed. It is three millimetres in diameter, and consists of an internal globular nucleus of granular texture, rather more than one millimetre in diameter, surrounded by a thick testa or outer envelope of radiating fibres. The fibrous part is in the same state of preservation as one of the kinds of associated fossil wood. the walls of the fibres being carbonized and the cavities tilled with transparent silica. Under high powers the " sjiore-like bodies " referred to by Mr. Etheridge resolve themselves into alternate swel- lings and contractions of the cavities of certain of the fibres, others presenting a more uniform cylindrical form. The latter occiisionally show the irregular transverse bands observed in the wood of I'rofu- tii.rites from the same locality. The internal nucleus i-> ajiparently wholly granular, as if it had been composed of parenchymatous tissue. There are in my cabinet specimens of similar bodies in a jjvritized state, from the Upper Silurian (Lower Helderberg) of Cape lion Am:, in New IJrunswiek, w here they are found associated with fragments of wood of I'rotot(ia-i(ts. Though on the whole less perfectly jtre- terved, as to structure, than the Welsh specimens, when sliced in certain directions they jjreseiit traces of a micropyle and embryo, and are, in my judgment, true seeds. There seems "little doubt that these New Brunswick specimens and those from Corwen may be referred to lirongniart's genus J^theo- itsta, and that they are nearly allied to my yEtlevtcsta ilevonica from the Devonian of Scotland (discovered by IJev. Thomas Brown, of Edinburgh). In connexion with the structures observed in the Corwen siiecimens, it is worthy of note that Erongniart says of his species ^'. sulir/lohosa, from the coal-formation, that the testa is " thick, homogeneous, formed of fibres or elongated cells perpendi- cular to the surface. TJitS( Jihns nj)jii7« 06. s7rt is undoubtedly a seed, and he compares it with tlie nut-like seeds of Taxinea:. Paclnjtliera has now been found associated with Protota.vitiS, not only at Corwen, but also in the Upper Ludlow of Engliind, in the Upper Silurian of Ca])e Bon Ami, and in the Lower Devonian of Bordeaux (iunrry opposite Campbcllton in New Brunsw ick ; and since the structure of the Corwen sjiccimen corresiiomls with that of /'/(/- * Aiiimlf-; di's 5«c'ieiuT?. lomo xx. srvie ;'>. ■■rf.jar ■ ■^m;<:;r:^ ag?:: jssimw^^ . PACfirrUECA FttOM THE UKNBIaasUIRE GRITS. 107 totaxites,iho pro-tuniption becomes strong that the connexion is not accidental. Usuler these circumstances, and considering the Taxine affinities of Jutheotesta, it would Bcera that Pachijtheca may bo accepted as affording some corroboration of the gymnospermoua nature of ProtoUixites*. Dr. Hicks has also sent a sjwciraen of the so-called " micro- spores " found with Fiuhiithecit. They occur in this specimen in a little semicircular patch or group, and are represented by mere im- pressions without any trace of organic matter. The lobed or fur- rowed appearance which they present gives to some of them tho aspect of tctra.spores enclosed in mother-cells, like tho •' Triploi^po- rltes" of Brown, in which case they might, as suggested by Mr. Carruthers, be Lycopodiaccous ; but these furrows are .so irregular that they may be accidental wrinkles. The occurrence of these objects in patches or groups suggests affinities with the Parka (hdpiensf of Fleming, a Devonian fossil at one time believed to be vegetable, but more recently referred to ova of (/'rustaceans. Similar groups of small rounded bodies occur in the Devonian of Gaspe ; but 1 have not been able to decide as to their nature. Discussion. The President referred to the wide interest which tho discoveries ot Dr. Hicks had evidently excited. Mr. Carruthers referred to a specimen sent to him by Dr. Dawson, which had its structure beautifully exhibited externally from weathering, and which ho hoped to study by means of sections. He thought that Dr. Dawson's ideas were the result of ha\nng examined the specimens by imperfect means. He insisted that tho minute structure of these plants was quite dif- ferent from that of Conifers. The stems are made up of inter- lacing tubes : tho smaller, which cros.scd the larger oblii[Ucly, were not spiral fibres inside wood-cells as supposed by Dr. Dawson. He thought no one accjuaintcd with the minute structures of Coni- ferous wood and of Alg;e could be led to accept the views of Dr. Dawson. The pseudo-exogenous structure is found in some living Algie. as in Lauu'iKtri'i. \\ith respect to Pitchittheca he had always experienced great difficulty at arriving at any conclusion. He * It oeoiirs to iiio to add here that the beds in which iVty^''((x/('f.'^ is met with, iu Gaspe nud near Caiiipbellton, contain no marine remains, but only hind-plants; and tlu)iit;b it wi/dd appear that m the Corwen beds the plants are associated with marine remains, vol the natnre of the specimens sent to me is evidently of littoral rather than deep-sea character, and here also they are associated «ith land >egetation. These modes of occurrence, as I have elsewhere pointed out, are not in harmony with the supposition that in tlicse plants we nave to deal with great oceanic^Alfja'. Nor does this supposition accord witli the fact that tlie wood of Pratutaxitcs retains its form and is silicitled in beds in whicli herbaceons land-i)Iants are perfectly flattened. t Lyell, 'Sludent's Elements,' p. 144; Nicholson, ' Pala!ontology,'_ \ol. i. p. 382"(Dr. Ilicks bns, 1 see, made the same suggestions iu his "Additional Notes," Quart. .Journ. Gcol. Soc, Feb. 1S82). m w< 108 PRINCIPAX DAW80H 05 PKOTOTAXITES AND thought that Sir Joseph Hooker was justified in referring it to LycoiK)diaceae from the materials at his command. He had long known that Pachytheca had a cellular structure fillinf? its inte- rior, consisting of tubular cells like those of the wall, but matted tofjfther. He was inclined to duubt whether they arc really vege- table, and may not be animal remains. Mr. Storric, of Cardiff, had sent him, years ago, well-preserved and beautifully prepared sections of I'achiftheia showing the whole from centre to circumference ; these led him to doubt their vegetable origin. He wished that zoologists would examine rachijthnca. He was satisfied, from the specimens on the table exhibited by Dr. Sterry Hunt, that the Eopteris of Saporta is really not a plant but a crystallization of pyrites, as suggested by M. Meunier-Chalmas. Dr. DrNCAN remarked upon the wonderful discrepancies of opinion that prevailed. He did not regard the central part of Puchiitheca as a mycelium. He regarded it as the float or conceptacle of a seaweed. Prof. JcDD stated that he exhibited, on behalf of Mr. Thiselion Dybr, two sections of Pcu-hi/theca. Mr. Thiselton Dyer regretted that ho was unable to be present at the Meeting, but had sent Prof. Judd a letter, from which he read the following extract : — '• Kew, November 15, 1881. '• I have to thank you for drawing my attention to the paper and discussion in the August number of the Quarterly Journal. Having read this, I venture to think that the specimens which I am placing in your hands my be found of some importance if exhibited at the meeting. " Their history is briefly this. Some time ago Sir Joseph Hooker received from Mr. Grindrod a number of specimens of Pachytlieca in situ on pieces of rock. As these examples of tlie fossils were apparently well preserved, two or three were detached and intrusted to Mr. Norman, who made the sections which are now in your hands. Sir Joseph Hooker did not see his way to any definite con- clusion as regards the structure which they exhibited. He, how- ever, allowed me to examine them, and they have since remained in my possession. The conclusion which I arrived at was that their structure agreed, in general plan, with that of Codium, as shown in Kiitzing, ' Phycologia Generalis,' pi. 42. f. 1. " As a possible algal nature has been suggested for Pachi/theca by Mr. Etheridge, I think it may not be considered presumptuous on my part to now state that I have been of opinion, ever since I studied the sections, that Prototaxites and Pachi/thefa are both refer- able to the same morphological type of structure. The radiating cells in the latter terminate internally in loosely interlacing slender filaments, with which the central cavity has been apparently fiUed. Paclujtheca does not resemble any type of sporangium with which I am acquainted ; the structure, as displayed in the specimens, has a certain resemblance to that of the sporocarp of Pilalaria ; but I cannot reconcile what 1 have seen of it with the supposition that it isnPK PACHTtHECA FROM TUT. DFNBIfiHSniRE OBITS. IM was a reproductive structure belonging to any typo of vascular crypt ogiim. " According to the view which I take of Pachitheen, it was an algal organism, closely resembling in essential structure a dimi- nutive Ciyilium, but with the ])eri[>heral cells branched instead of simple. I do not see any evidence to lead mo to 8upi)ose that it was related to J'rototaxites as a sporangiiil organ. The existence of Pri>totii.vitfs on modern biological views necessarily implies the existence, at some time or other, of allied forms ; and I do not see why J'achylheca should not have been a contemporan ous one." Dr. Hicks explained the way in which the specimens had come into Principal Dawson's hands. The 1'resident supported Mr. Carruthers's views as to the non- coniferous character of Nematojthyait. With regard to Pachyiheca he felt great doubts. I - *