« PreviousContinue »
fossils with certainty. The general form and sculpture suggest near relationship with the known species C. cashmerinsis.1
Genus LAMELLIDENS Simpson.
1900. Lamellidens, Simpson, Proc. Nat. Mus., Washington, XXII, p. 854. 1914. Lamellidens, Simpson, Descript. Cat. Naiades, p. 1165.
1918. Lamellidens, Prashad, Rec. Ind. Mus., XV, p. 145.
1919. Lamellidens, Annandale & Prashad, Rec. Ind. Mus., XVIII, p. 59. The genus Lamellidens is widely distributed in India and Burma. Forms of the widely distributed species L. marginalis (Lamarck) are also known from Afghanistan and Baluchistan. No Unionids have, however, been recorded from the Kashmir territory and when in Kashmir in 1921 I did not, in spite of careful search all over the area, come across any Unionids. It is, therefore, of great interest to record a fossil Unionid from Dr. Wright's collection which can, with little hesitation, be assigned to the genus Lemellidens. This discovery completes the link in the chain of distribution of the genus Lamellidens which thus extends from Baluchistan, Afghanistan through Kashmir to the Punjab and thence through the Gangetic plain to Assam and Burma on one side and to Peninsular India and Ceylon on the other. No member of the genus has hitherto been found in Sindh.
(Plate 29, figs. 9, 10.)
In assigning the fossils obtained by Dr. Wright to the genus Lamellidens I have been guided by the general facies of the shell, the type of beak and traces of the hinge-line. Unfortunately, the rest of the hinge is not preserved, nor is the external surface of the shells to be seen in the remains of shells in the casts collected. I have, therefore, not attempted to give these fossils a name, but it may be noted that the species is nearly allied to L. marginalis (Lam.).
The fossils in Dr. Wright's collection were obtained from north bank of Kakriaj Nar mile from the east boundary of Survey of India sheet 43.
Deshayes, Proc. Zool. Soc., London, p. 344 (1854).
EXPLANATION OF PLATE 29.
LAND AND FRESHWATER SHELLS FROM KASHMIR KAREWAS.
(All the figures are from direct photographs of specimens.)
1. Compressed shell from Kashmir Karewa; natural size.
BITHYNIA TENTACULATA (Linn.) var. KASHMIRENSIS, Nevill.
2, 3. Dorsal and ventral views of two recent shells out of the type-series from Srinagar, Kashmir: × 5.
4, 5. Dorsal view of two fossil shells from the Karewas of Kashmir.
GYRAULUS PANKONGENSIS (Nevill) v. Martens.
6, 7. Dorsal and ventral views of two fossil shells from the Kashmir Karewas
8. Two valves of a shell from the Kashmir Karewas: X 5.
9, 10. Natural size photographs of two casts with remains of shell-valves.
REPORT ON THE EXAMINATION OF BURMESE LIGNITES
has been known for many years that coal deposits exist in many districts of Burma and that several of these contain considerable quantities. Spasmodic efforts have been made to work some of these deposits but hitherto they have not been attended with success. The production figures are ample proof of this. For the last 5 years the figures, taken from the Records of the Geological Survey of India, are as follows:
There are two main reasons for this small production, (1) inaccessibility of many of the deposits, (2) the poor quality of the coal. If the material exists in quantity the former presents no difficulty. As to the latter, the majority of the coal of Burma is "lignite" or brown coal" which has high moisture and ash contents and small fixed carbon. The calorific value is low in consequence.
Most lignites, before they can be used successfully as a fuel have to undergo a process of treatment, which varies according to the composition of the raw material and also on the manner in which the fuel is to be employed. When used for power produc
tion it is necessary to fit special types of grates and hearths, and, stoking has to be carefully regulated.
Methods of treating Lignites.
The chief methods of treating lignites are:-air drying, briquetting, distillation, and gasification. Air drying is the simplest as the fuel is used in the natural state after a proportion of the excess moisture has been driven off. Briquetting entails elaborate machinery as the lignite has to be crushed, screened, dried and then moulded into briquettes under great pressure. It is the commonest form of treatment for a powdery coal. Distillation is suitable for lignites which have a high content of bituminous matter. Oil, gas and coke are the chief products obtained. Gasification is employed when the percentage of bituminous matter is small. The producer-gas obtained can be utilised either direct in gas engines or to fire boilers.
Compared with ordinary bituminous coal, the exploitation of lignite is beset with considerable difficulties.
When the question of testing the Burmese lignites was raised by the Government, it was hoped that samples from all the coal fields would be included in the experiments Scope of Examination.
but, when the cost was ascertained, it was found that there were only sufficient funds for three complete tests. The Geological Survey were asked to select the three fields and to collect the necessary samples. The three fields considered to be of most economic value were accordingly chosen, namely:-Namma, Lashio and Pauk. The selection was a matter of considerable difficulty as the available information on these fields contained no estimate of quantity. The Kalaw and Henzada fields were considered to be outside the scope of the enquiry as these are true coals as distinct from lignite; the former being a Jurassic coal and the latter approaches the composition of an anthracite and is probably also of Jurassic age.1 Examination of the other important deposits will have to await the allocation of further funds. The Namma field lies on the southeast side of Lashio and extends to within 10 miles of the town, covering about 50 square miles. It was visited by Neotling in 1891.2 A more detailed examination of the field was made
Location of the fields sampled.
by Simpson in 1905.3 There appear to be two
1 Cotter, The Mineral Deposits of Burma, p. 18.
2 Noetling, Rec. Geol. Surv., Ind., Vol. XXIV, pp. 116-119.
Simpson, Rec. Geol. Surv., Ind., Vol. XXXIII, pp. 125-141
seams of economic value, one of which varies in thickness from 7 to 17 feet and over a proved distance of 2,400 feet is estimated to contain half a million tons. The coal seams are interstratified with soft beds of clayeyshales which would render mining operations difficult. The age of the beds is considered to be late Tertiary; probably Pliocene. The distance from Lashio railway station by cart road is 25 miles.
The samples from this field were taken from the north-east incline of the two driven by the Burma Corporation, east of Namma. Lashio is the present terminus of the Northern Shan States branch, Burma Railways. The coal deposits are found some 5 miles north of the town. Noetling visited this field also in 18911 but LaTouche and Simpson conducted excavations and made a thorough examination later. In this field also, the coal is interbedded with beds of sandy clays and soft sandstones and all lie below the level of permanent saturation. Seams varying in thickness from a foot to 33 feet were found. The age of the coal strata is thought to be late Tertiary also.
The samples from this area were taken from the bed of the Nam Yau river, half a mile west of the village of Hsunkwe and 11 miles north-west of the bridge on the cart road from Lashio to Nam Hkam.
The Pauk field is situated in the Pakokku district about 50 miles west of the Irrawaddy. The coal seams outcrop in the neighbourhood of the Yaw river some 14 miles south-east of Pauk, the town from which the field takes its name. A complete examination of the field was made by Cotter in 1913.3 The coal-bearing rocks belong to the Shwezetaw stage, the age of which is Lower Oligocene. Consequently this field is older than the Namma and Lashio fields. The samples were taken from three outcrops, the exact location of which will be found in the references given.
(1) Newè chaung, excavation No. 1.5
(2) Thongwa chaung, middle seam.6
(3) Yekyin chaung, excavation No. 2.7
All the samples were packed into empty kerosine oil tin and sealed in the field.
Noetling, op. cit., pp. 112-116.
LaTouche and Simpson, Rec. Geol. Surv., Ind., Vol. XXXIII, pp. 117-124.
Cotter, Rec. Geol. Surv., Ind., Vol. XLIV, pp. 163-185.
Vredenburg, Rec. Geol. Surv. Ind., Vol. LII, p. 364.
Cotter, op. cit., p. 180.
Cotter, op. cit., p. 178.
ibid, p. 170.