coal-mine has been discovered near Cape Town, etc." If the Cape colonial newspapers were as particular as the Times and other London papers, there would not be so many "mare's nests" as the Capetonians are constantly discovering, and which usually end in smoke.

NOTICES OF

MEMOIRS.

I.-RECORDS OF THE GEOLOGICAL SURVEY OF INDIA. VOL. I. PART 2. AUGUST, 1868.

THI

HIS publication contains miscellaneous notes and observations made by Officers of the Geological Survey of India.

Coal at Chenda.-Mr. W. T. Blanford, F.G.S., having been engaged in examining some coal seams discovered in the neighourhood of Chenda, here furnishes a report on the prospects of the coal being profitably mined. He states that although one seam is very promising, some further research is necessary before a decisive opinion can be formed upon this subject.

Dr. Oldham adds that borings have been carried out close to the town of Chenda, and have proved the existence of coal, about 2ft. 6 inches in thickness. The coal is said to be hard, but as no trial of it has yet been made, its quality is unknown.

Coal near Nagpur.-Mr. Blanford reports on the likelihood of coal being found near Nagpur. Although it is probable that the sandstones developed in the neighbourhood belong to the Indian coalbearing series, yet he has been unable to obtain any indications of coal.

By far the greater portion of the beds of this series in Nagpur are concealed by thick alluvial soil, and it is therefore impossible to say whether coal exists beneath it, or not. Mr. Blanford, however, points out a few localities where its presence is just possible, in order that, if advisable, borings may be made to determine the question.

Geological Notes on the Surat Collectorate, (Bombay Presidency).— Mr. A. B. Wynne, F.G.S., gives a general account of the Physical features and of the formations constituting this Collectorate, and he then furnishes some detailed notes on the rocks in various localities. Taken generally the district may be described as flat, with isolated hills on the south, and bordered on the east by a hilly and jungly tract.

The formations which occur are

Recent {Cotton soil.

Alluvium and river-beds.
Tertiary Nummulitic

? Trap.

The trap-beds consist of many varieties, ranging from solid basaltic trap to soft shaly-looking amygdaloid, the variously sized cavities of which are filled with zeolites of different kinds, and sometimes by transparent or amethystine quartz.

Resting unconformably upon the traps is to be seen a series of

VOL. VI.-NO. LV.

2

hard lateritic ferruginous rocks, coarse conglomerates, dull yellow earthy limestones, sandy and clayey beds; many of them highly fossiliferous, some largely made up of Nummulites, others of the separated valves of Balanide, with teeth of sharks, fragments of the carapaces of turtles, and bones as yet undetermined. From the evidence of the fossils, a Parisien' age has been assigned, by Dr. Stoliczka, to this series of beds. Sections of these Nummulitic beds, from one to three hundred feet in thickness, may be seen in many of the streams.

The alluvium is almost universally composed of a fine lightcoloured argillaceous loam, seldom pebbly or gravelly, and always formed from the decomposition of the local rocks.

The cotton soil covers the alluvium over many large tracts of the country. It is often of considerable depth, presenting the usual desiccation cracks, but without any circumstances to throw additional light upon its source or formation. It seems in this country at least to result from the decomposition of an alluvium largely made up of trappean materials.

Cretaceous Cephalopoda of South India.-Dr. F. Stoliczka records some recent observations which must be considered as a supplement to his volume on the Cephalopoda, already published.

materials have been procured, but from his having had last year the opportunity of examining, in London, Professor E. Forbes' original collection, made by Messrs. Kaye and Cunliffe, and also in different European Museums a large number of other species, with which Indian Cephalopoda have respectively been identified, new light has been thrown on some of the species, and some alterations in the names, etc., rendered necessary.

II. THE JHERRIA COAL-Field.

By THEODORE HUGHES, ASSOC. R.S.M., F.G.S., [Mem. Geol. Survey, India, Vol. V. Art. 4.]

HIS memoir is confined chiefly to a detailed description of the physical aspect and geological history of an area of not less than two hundred square miles, and which has been termed the Jherria Coal-field. It occurs a few miles south and south-east of Parisnáth, one of the highest mountains in Bengal. The field commences at a distance of about 170 miles from Calcutta, and extends in an east and west direction about eighteen miles, its greatest breadth, in a line north and south, being about ten miles.

The character of the ground is generally flat, and nowhere rises into undulating scenery; it is rocky, and covered by a very slight amount of soil, so that cultivation is not extensively practised.

Two series of beds are developed in the district, the lower, the Talchir; the upper, the Damúda; comprising a total thickness of 6,800 feet of strata, and forming a basin, the beds usually dipping at right angles away from the boundary, at varying amounts, towards a common centre of depression.

The Talchir series consists of a Boulder-bed, and above it flaggy green shales and mammillated sandstones.

The Damúda series, which has three sub-divisions, is characterised by its containing coal. The bottom beds consist of felspathic grits, sandstone with seams of coal, carbonaceous shales, conglomerates, etc.; then come carbonaceous shales with ironstones, forming the middle sub-division; and at the top, thick-bedded, and yellow slightly calcareous sandstones. With the exception of the middle sub-division, coal occurs at all depths in the Damúda series.

The Boulder-bed of the Talchir series, which is, more properly speaking, a coarse conglomerate, consists mainly of masses of gneiss and quartz, of about one foot in length and three to six inches in breadth, imbedded in a matrix varying in texture from a coarsegrained sandstone to the finest silt. One is apt, at a first glance, to attribute to the agency of ice a share in the transportation of the larger blocks. But the author states that on examining the evidence he can find none to justify such an hypothesis. No scratchings or groovings occurred on any of the stones, nor have they been derived from any very distant source. The larger blocks sometimes retain the primitive form in which they were broken off from the parent mass. A recent visit to the Straits Settlements led the author to conclude that the beach deposit which is forming there at the present time is analogous to the so-called Boulder-bed.

No coal has as yet been discovered in the Talchirs. In the Damúda series the coal-seams appear to be very irregular, and to vary much in thickness. In the upper sub-division there is a general tendency to ignition in all the coal seams, owing, most probably, to the presence in them of iron pyrites, which gives rise to spontaneous combustion. Metamorphism is produced in the shales either above or below, and it is of a varied character. Sometimes the beds become like well-burnt bricks, or obtain a rough vesicular appearance.

A caking variety of coal is procured at one locality, which moreover gives out a copious supply of gas, burning with a rich yellowish white carburetted flame.

Many seams are much injured by the trap-dykes which ramify through them and render the coal useless. In one instance the coal assumes every variety of form and texture, passing from a light vesicular pumice-like stone through all the intermediate stages until it becomes a hard dense columnar mass.

The seams vary in thickness from a few inches to twenty feet, and more.

The quality of the ironstones is very poor, and they are so siliceous that even the native Kummars can do nothing with them. In a note, appended to the report of Mr. Hughes, Dr. Oldham says, that if, in calculating the probable quantity of coal obtainable from this field, we take twenty feet as a fair average thickness of workable coal-the mean of all the sections drawn by Mr Hughes and make allowances for the impersistence of the beds. by supposing that they will extend over less than a third of the area of the field,-say sixty square miles, we should have an available supply of coal amounting to about 465 millions of cubic yards, or, rough y, tons.

But every such estimate must be of the rudest kind possible with reference to a coal-field, in which not a single pit has yet been sunk, nor a single opening made.-H. B.W.

REVIEWS,

1.-THESAURUS SILURIOUS-THE FLORA AND

FAUNA OF THE

SILURIAN PERIOD. By J. J. BIGSBY, M.D., F.G.S., etc., etc. London, 1868. Van Voorst. 4to. pp. 268. [Second Notice.]

(Continued from the November Number, p. 521.)

"N his introduction, Dr. Bigsby gives an analysis of the classes Gasteropoda and and Trilobita and Brachiopoda as

in stratigraphical and geographical distribution ;-space, however, entirely forbids our attempting any fresh analysis for this notice, the subjects being so prolific. Under the head Gasteropoda in the introduction, pp. vii.-x., several tables are constructed; that on p. vii. gives the geographical summary of species for the chief areas in which Silurian life is known ;-27 areas are given-12 on the American Continent, 3 in Britain (England, Ireland, Wales), 9 European, 1 South Australian, I Tasmanian, and 1 for North India; but in the chief and detailed summary, p. 169, in the body of the Thesaurus, 43 areas are given-25 American, 15 European, with India, Australia, and Tasmania in addition, and an analysis of all the genera (51) and 895 species, with their appearances, numbers, and habitations. The table (B) also containing those genera having the greatest range in time and space, with the number of species in each and number of countries inhabited-show a kind of analysis that may be carried to any extent. The result of one line for the Pleurotomaria is, itself, suggestive. This genus contains 171 species, and they are distributed over 34 large countries [the fossiliferous Silurian area of Canada alone is 70,000 square miles]. This dispersion or distribution applies to all the 51 genera, and species belonging to the class Gasteropoda, the ratio of the proportion of species in each genus, and the different degrees of distribution being due to life habits, associated faunæ, sea-bottom, temperature, locality, etc. The Thesaurus tells us that 18 genera out of the 51 are known only in, and each confined to one district, and 12 of these genera possess only one known species in each, and 7 have 2 species only; supposing the genera to be well established, we only require further research, probably, to discover many other species. We have, however, much doubt as to the value of such genera as Calyptræa, Cerithium, Delphinula, Littorina? Naticella, Phasianella, Rotella, Siphonaria, occurring in the Silurian rocks, until we certainly know more of them, and it is amongst such that the few forms, above named, seem to occur. We mention this to guard against drawing conclusions hastily upon doubtful determinations, as per centage in generic life is of importance on either side, and leads to false conclusions upon the question of first appearance, locality, etc., as propounded in the 7 doctrines laid down in the introduction to the Thesaurus. Particulars are given, in the body of the great table, of no less than 894 species of Gasteropoda. The increment and decrement of the Gasteropoda in time, as exhibited over large areas through their physical history and mutations, is one of the many problems which the Paleontologist is constantly called upon to investigate, and thus to account for the "rise and decline," "first appearance," and "extinction" of any group. Dr. Bigsby, at p. ix. (table C), points out in 8 subdivisions of the Silurian system, the rise, culminating point, and decline of the Silurian Gasteropoda;-their extinction, like that of other groups, which really took place at the close of the Silurian and commencement of the Old Red Sandstone, in Britain, is a problem geologists have yet to solve. The table D, on p. ix., is too important to be passed over; it is, as the author terms it, a "time table" of all the Silurian Gasteropoda, showing the number of species in each genus through the four Silurian stages, and if the species in the work may all be relied on, opens up a mode of time and space analysis whereby any known area, having one or all the stages, may be "censused." That this early epoch in the Earth's history should have contained so great an assemblage

of Gasteropodous mollusca, indicating maturity in time and a fitness of conditions for organic life—may seem remarkable—but it will appear even more so if we examine into the life-history of the Cephalopoda, which, during the same epoch, numbered some 1400 species!

Trilobita.-This is the second group selected and treated of by the author, and necessarily so, for they are the medals and type of life peculiar to the seas of Silurian time, and are almost universally spread over the globe. We find 119 genera and 1680 species occupying the rocks of no less than forty-four countries; 74 genera and 1000 species are primordial, and 46 of these 74 [so called] primordial genera are not known above this stage, no one (so far as we know) of the 235 early species, recurring in the overlying Caradoc of any country, or in the Trenton beds of America-and, according to the Thesaurus, we arrive at the fact that "a primordial form has usually a considerable vertical range within its native stage, and there only;"1 and Barrande and Bigsby, through the labours of Hall and Billings, 、 and the American Palæontologists, determine from materials now collected together in the Thesaurus, "That life began earlier, and more abundantly in the valley of the St. Lawrence and Mississippi than in Europe." This we may qualify, however, through negative evidence, from want of more complete knowledge of the extent and nature of the rocks once occupying the area west of St. David's Head and the south of Ireland, and, indeed, the whole bed of the Atlantic, and, perhaps, also the Bay of Biscay,--for daily we are adding new facts connected with the older and underlying rocks below the "Lower Lingula flags" of the South Wales Promontory; and what do we yet know of the Western promontories of Ross and Sutherland and the Hebrides, or those rock-masses termed the fundamental Gneiss of Murchison. Could we but restore or examine these sub-atlantic deposits in South Wales and North-west Scotland, the St. Lawrence basin and Britain would, probably, be one in age and life, one in time and condition. Research tells us that the primordial Trilobites alone, in the western valleys of America, number some 40 genera and 200 species, and these assembled in two similar foci or centres, Wisconsin and Lower Canada. Sweden has its own primordial fauna, represented by 18 genera and 56 species; Bohemia, 8 genera and 28 species; Great Britain and Ireland, 11 genera and 33 species.

The author of the "Thesaurus" determines that out of the 57 American genera, 16 are exclusively localised in that hemisphere, and of the 116 European genera, 69 are not known elsewhere; the work also shows that 31 genera have each only one species, and that only one genus of the 31 occurs out of its native area,Polyeres (Bohemia and France); and the largest Genera have been subjected to the widest dispersion, thus—

Calymene, with 61 species, is known in 29 regions.

We know also that the same species in large genera inhabited many regions widely separated, thus proving their dispersion and distribution over great areas. The British Calymene Blumenbachii and C. senaria, inhabited 17 regions, from the Trenton Limestone of America to the Wenlock of Wales, Russia, Sweden, Norway, Esthonia, England, Ireland and Scotland. Encrinurus punctatus 8, and in two quarters of the globe. Bumastus (Illanus) Barriensis in 10, and all in the Upper Silurian deposits from Sardinia to England, and the American continent. In the year 1858, 126 species of Trilobites were known to Great Britain and Ireland, but in the new (4th) edition of Sir Roderick Murchison's "Siluria," is catalogued 224 species, or one hundred additional forms have been added to the Silurian fauna in 10 years.

At page 71 of the "Thesaurus," Barrande has enumerated for Dr. Bigsby no less than 79 species of Trilobites discovered in the Bohemian basin since 1852

1 We do not here discuss the breaks in time either physically or paleontologically; it is too large a subject.