I. I-~ISTORICAL. Dr
Total Page:16
File Type:pdf, Size:1020Kb
Downloaded from http://jgslegacy.lyellcollection.org/ at University of Oregon on June 24, 2016 604 =e. L. v. DAnTO~X OX TUE [Nov. X908 , 31. NOTES 0r~ the GEo~oG~r or BcR~A. By LEONARD V. DALTON, B.Se. (Communicated by Dr. A. S~ti'l'rt WOODWAI~iO,F.R.S., F.L.S., V.P.G.S. :Read April 15th, 1908.) [1PLATES LIV-LVII--FosslLs.] I~ is the object of this paper to present the results of geological expeditions in the Irawadi valley carried out by my uncle :Mr. W. H. Dalton, F.G.S., and myself in the season of ~1904-1905, and by myself alone in 1905-1906, and to correlate these observations wilh those made by previous writers, thus summarizing our present knowledge of the geology of Burma generally and of the Tertiary System of that country in particular. To this end it is divided into the following sections :- :Page I. Historical ............................................................... 604 II. Original Observations ................................................ 607 III. General and Stratigraphical ....................................... 617 IV. Paleontology ......................................................... 622 V. Recapitulation ......................................................... 641 I. I-~ISTORICAL. Dr. Fritz Ncetling in 1895 ~ reviewed the work done on the geology of Burma before that date, pointing out the remarkably-accurate hypothetical arrangement of the rocks of Burma made by'Buckland in 1828, ~ and the absence of subdivision of the Tertiary System previous to W. Theobald's paper on Lower Burma in 1873. 3 In this summary the ' Axial Group' of Theobald is referred to as certainly not of Triassic age--a statement controverl-ed by later examination of the fossils of tim Arakan Yoma and other parts of Lower Burma-- although folmd true in the sense that the ~,-'roup is~ a comptex~, one (as we now know), and neither Triassic nor Cretaceous alone, but assignable to both of these. While Dr. ,Ncetling's paper thus reviews the greater number of the works published on the geology of Burma, and in particular those relating to the Tertiary of the better-known regions of the Irawadi basin, there are certain other papers to which it is necessary to refer here, as they deal with the outlying districts. Of these the earliest is that of E. J. Jones on the coals of the Chindwin Valley/ wherein he describes the 1 :Rec. Geol. Surv. India, vol. xxviii, p. 59. Trans. Geol. Soe. set. 2, vol. ii, pt. iii, p. 377. The fossils collected by J. Crawfurd near Singu and Yenaugyat on the Irawadi, referred to by Buekhmd, are in the Museum of the Geological Society, and apparently include several of the forms named many years later by Dr. INeRtling. They are of especial interest, as being the first fossils from Burma to reach this country. ' On the Geology of l~egu ' Mere. Geol. Surv. India vol. x p. 189. ' ~Notes on Upper Burma' Rec. Geol. Surv. India, vol. xx'(1887) p. 170. Downloaded from http://jgslegacy.lyellcollection.org/ at University of Oregon on June 24, 2016 Vol. 64. ] aEo~oGr o~" ~v~A. 605 lithological character of ~he rocks of that district, but wrongly assigns a Cretaceous age to the Miocene coals of the Upper Chindwin, on the ground of the occurrence in them of fossil resin. In the same paper the Tertiary coals and lignite of the region south of Mandalay and in the Shan Hills west of Yamethin are described; while Dr. N(etling's report of 1~91 ~ points out the interesting fact that Miocene coal is found only in the north-east-to-south-west valleys of the Shan Plateau, which tableland is formed of Palaeozoic and metamorphic rocks. Lastly, the same author in his papers of ]$93 '~ and ]b94 z indicates the presence of Miocene rocks in the far north (amber-mines) and near Wuntho. Passing to the review of work subsequent to the 1895 summary, ave have the late G. E. Grimes's paper on the geology of the Yenangyat oilfield, and of Gwegyo and other localities in the Myingyan district2 Dr. Noetling's description of the Miocene ~bssils of Burma was published in 1.901 5, and has become a classic in Burmese geology. In 1906, Mr. G. H. Tipper, in a preliminary note on the Trias of Lower Burma, G refers to specimens of Halobia Lommeli, Wissm., found in Theobald's collections, which were labelled as coming from the Karenni, pointing to the occurrence of Triassic rocks in the east of Lower Burma. He here notes that the Trias of the Arakan Yoma is of less extent than was indicated by Theobald in 1873. In the following year the same writer published a further note 7 showing the complexity of the Axial Group, which he divides into (1) Upper Axials, including Cc~rdita-Beds ~Creta- ceous], IIalobia-Limestones [Trias_~, and shales, sandstones, and grits ~Trias ?j ; and (2)Lower Axials, consisting of [unfossiliferous] flaggy shales and sandstones. In 1906, Mr. l~. D. Oldham also published a paper on the ex- plosion-craters of the Lower Chindwin district, west of Monywa, s these being identical with the volcanic hills referred to by Jones in 1887 ~ as an extension of the line of vulcanism running north and south through Narkondam and 'Paopadaung.' In 1906 also, Mr. E. H. Pascoe published accounts lO of the stratigraphy of a Miocene area east-north-east of Kabat in lat. 2i ~ 4' N., long. 95 ~ 20' 30" E., and of that of Gwegyo, with a later note ~t in the following year on some fossiliferous lenticular marine limestones exposed in the Yenangyoung Miocene area in the 'Yenangyoung Stage,' the fossils found here prior to this time being chiefly derived from the lower division or ' Promeian' of Dr. Ncetling. 1 , Report on the Coalfields in the Northern Shan States' Rec. Geol. Surv. IHdia, vol. xxiv, p. 99. .2 , On the Occurrence of tlurmite, &e.' 7.bid. vol. xxvi, pt. i, p. 31. ' Note on the Geology of ~Vuntho ' Ibid. vol. xxvii, pt. iv, p. 115. 4 Mere. Geol. Surv. India, vol. xxviii, pt:. i (1898) p. 30. :' Palmontologia Indiea (Mere. Geol. Surv. India) n. s. voI. i, no. 3. G l?~ee. Geol. Surv. India, vol. xxxiv, p. 134. 7 It,id. vol. xxxv (1907) p. 119. s [l~id. vol. xxxiv, p. 137. .9 Ibi& vol. xx, pp. 176-77. ~o 1hi& vol. xxxiv, p. 242. ~ 15id. vol. ~xxv (1907) p. 120. 2s2 Downloaded from http://jgslegacy.lyellcollection.org/ at University of Oregon on June 24, 2016 6t)6 )it{ t I;. v. l>_~.I,'rox ox :."n i: [N4,v. J9o8. Bv the last-named author, the Tertiary rocks of Burma were elassified as under :-- &'firs. 5"zt bd i ~,L,i,)~ . 7"h ieZ'~ e,ss Im,.w.tt*t { Upper lr'~wadi Series. le 20.0t,1 SEIU'".S. Lower lvawadi Series. j t t'e,,u Division. Yenangvotmg Stage. 8Emr,.s. I ]las~ein ])ivision. 1,'_"(tti . Chin ])ivision. 10,1!ttlJ+ (1) Arakan Series. a) Chin D ivision.--This approximately corresponds with the "Axial Series' of Theobald, though to what. extem is not, exaelly known. In any case, it is certain that portions of it are, as we have seen, Triassic and Cretaceous, while it may be, as suggesh.,1 by Dr. Nmlling, that it inelndes no Tertiary reeks. [n view of the supposed occurrence of Halobi~t Lommeli north-east of l{an~oon, it is justifiable to l)resume that the Chin Division is represented ther(, also, though not recorded 1)y any observer. (b) Bassein Division.--.,k series of impure fossiliferol> limestones, blue marls, and hrown or grey sandstones, wilh 2Vu'm~n:lites, etc., and at the top a band (more than 10 feet thick~ of highly-t;)ssiliferous red mmmmlitie limestone. ]legarded as Eocene. (c) Pegu 1)ivision.--l)ivided by Dr. Nmtling into two sub- divisions, I'romeian and Yenangyoungian, the former (and l.ower) being distinguished by its blue clays and grey s'mdstones from the upper, where olive is the predominant eolour. Correlated with the Miocene of Europe. Very few tbssils are known from the Promeian, and these only from one bed near Yenangyoung, "tlthough numerous species ha~/e been collected from the Yc]mngyoungian, indicating two facies, one brackish, the other marine. (2) Irawadi Series. The subdivision of this series suggested by Dr. Nmtling is mdv preliminary, 11o extensive ex,nmina~ion havipg been yet carried out. The group is considered by that author to bc of I'liocene age and equivalent to the Siwaliks of India, which it nmeh resembles. (a) Lower Irawadi Series.--Yellow friable sandstones, with bones and much tbssil wood. (b) Upper Irawadi 8eries.--Sandstones similar to those of the lower division, wit.h no bones and Icss fossil wood. ]t is extremely donblt'ul whether the thickness of this series is as great as that suggested, but. there are no data available for correcting the earlier estimate. Downloaded from http://jgslegacy.lyellcollection.org/ at University of Oregon on June 24, 2016 u 64.~] ~OLO~:r O~ ~VIr 607 It is evident that some modification of the foregoing elassifi- c.ation is desirable, in view of the later evidence brought forward as to the ages of the lower members of the succession ; these changes may be more fitly'suggested in w I:[[, when considering the general results of tim study of the various sections now to be described. The additional information contained in the sequel relates to the Pegu and Bassein divisions of the Arakan Series, new localities of the ibrmer having been visited, while numerous fossils from the latter are fbr the first time described.