merates and describes the changes that plants, animals, and minerals, the atmosphere, and the waters of the globe, have undergone from the earliest geological periods up to our own time, and which even instructs us in the earliest history of the human species, that it offers no gratification to the philosopher? Can even those who estimate the value of science, not by intellectual desires, but by practical advantages, deny the importance of Geology, certainly one of the foundations of agriculture, and which enables us to search out materials for numberless important economical purposes?

Positive geology or geognosy, as Cuvier, in his life of Werner, remarks, originated with that remarkable man; and all that has been done towards unravelling the structure of the crust of the earth since his views were made known, has been in harmony with them. The Editor remarks,

"Geology took its rise in the Academy of Freyberg, with the illustrious Werner, to whom we owe its present interesting condition. This being the case, we ought not, (as is at present too much the practice), amidst the numerous discoveries in the mineral kingdom which have been made since the system of investigation of that great interpreter of nature was made known, forget the master, and arrogate all to ourselves. In this island, Geology first took firm root in the north: in Edinburgh, the Wernerian geognostical views and method of investigation, combined with the theory of Hutton; the experiments and speculations of Hall; the illustrations of Playfair; and the labours of the Royal and Wernerian Natural History Societies, excited a spirit of inquiry which rapidly spread throughout the empire; and now Great Britain presents to the scientific world a scene of geological acuteness, activity and enterprise, not surpassed in any other country."

Independent of the numerous additions to the text of the Essay, the editor has added upwards of two hundred pages of notes and illustrations on the following important topics.

On the Subsidence of Strata. Deluge. Formation of Primitive Mountains. The distribution of Boulder-Stones in Scotland, Holland, Germany, Switzerland and America.

The Alluvial Sand of the Danish Islands in the Baltic, and on the coast of Sleswigh.

The Sand-Flood.-Sand-Flood in Morayshire. Sand-Flood in the Hebrides, &c. Moving Sands of the African Deserts.

Action of the Sea upon Coasts.

The Growth of Coral Islands.

The Level of the Baltic.

Fossil Remains of the Human Species.

Account of the Displacement of that part of the Coast of the Adriatic which

is occupied by the Mouths of the Po.

The Universal Deluge.

The Action of Running Waters.

Connection of Geology with Agriculture and Planting.

Account of the Fossil Elk of Ireland.

Account of the Living Species of Elephant, and of the Extinct Species of Elephant or Mammoth.

Account of the Caves in which Bones of Carnivorous Animals o

quantities.

Cave containing Bones at Adelsberg, in Carniola.

secta; with their Geognostical Number and Distributio

View of the Genera of Fossil Mammifera, Cetacea, Aves, P

View of the Classes, Orders, or Families of Animals, occu
Fossil state; with their Geognostical Distribution.

This work, so rich in well authenticated and well arranged geological facts, and abounding in beautiful views of the mineral and animal kingdoms, cannot be too strongly recommended. It ought to find a place in the library of every one who takes an interest in the natural, and even the civil, history of the planet we inhabit.

2. Illustration of the Geology of Sussex, containing a general view of the Geological relations of the South Eastern part of England; with Figures and Descriptions of the Fossils of Tilgate Forest. By GIDEON MANTELL, Esq. F. R. S. Fellow of the Royal College of Surgeons, F. L. S. M. G. S. &c. One volume quarto.

M. MANTELL is already advantageously known to geologists, by his interesting and valuable volume on the geology of Sussex. The present elegant work is a further proof of his skill and activity; and, therefore, we truly regret to find, from the preface, that this will, in all probability, be the last time we shall have an opportunity of noticing his geological labours, as he intimates his intention of taking leave of this department of Natural History. Sussex, Mr Mantell informs us, is composed of portions of all the secondary formations of England, from the Purbeck limestone to the tertiary deposits; outliers of the London and Isle of Wight basin, and accumulations of diluvial and alluvial matters. The regular deposits are the plastic clay and London clay, chalk, shanklin sand, weald clay, and the sands and clays of Hastings. All these different deposits are carefully and luminously described; the various organic remains with which they abound well described, and many of the more remarkable represented in a series of twenty beautiful lithographic plates. The stratification of the Forest of Tilgate, which has excited so much interest on account of its organic remains, is fully described, and evidence adduced of its being older than chalk. The description of the organic remains of Tilgate Forest is concluded with the following striking observations, which also close the work.

"In concluding this description of the organic remains of Tilgate Forest, we would repeat, what we have elsewhere remarked, that the vast preponde

rance of the land and fresh-water exuvia over those of marine origin, observable in these strata, warrants the conclusion that the Hastings beds were formed by a very different agent from that which effected the deposition of the Portland limestone below, and the sands and chalks above them. The seas in the primitive ages of our planet were inhabited by vast tribes of multilocular shells, which, however variable in their species, were not only of the same family, but also of the same genera, namely, Belemnites, Ammonites, and Nautilites. These shells, if we may draw any conclusions from our knowledge of the habits of the recent species of the only genus that still exists, were indisputably inhabitants of the ocean; and the presence of their remains in any considerable quantity in a stratum, affords a fair presumption that such stratum is a marine deposit. The converse of this proposition, we conceive, must hold good in a case like the present, where not a vestige of these ancient marine genera can be traced, among innumerable remains of terrestrial vegetables and animals, and of fresh-water testaceæ. The occasional occurrence of marine exuviæ affords no grounds for a contrary opinion, since this fact is no more than might be expected under such circumstances, and is in strict accordance with what may be observed in the deltas and estuaries of all great

rivers.

"We cannot leave this subject, without offering a few general remarks on the probable condition of the country through which the waters flowed that -deposited the strata of Tilgate Forest; and on the nature of its animal and vegetable productions. Whether it were an island or a continent, may not be determined; but that it was diversified by hill and valley, and enjoyed a climate of a higher temperature than any part of modern Europe, is more than probable. Several kinds of ferns appear to have constituted the immediate vegetable clothing of the soil; the elegant Hymenopteris psilotoides, which probably never attained a greater height than three or four feet, and the beautiful Pecopteris reticulata, of still lesser growth, being abundant every where. It is easy to conceive what would be the appearance of the valleys and plains covered with these plants, from that presented by modern tracts, where the common ferns so generally prevail. But the loftier vegetables were so entirely distinct from any that are now known to exist in European countries, that we seek in vain for any thing at all analogous without the Tropics. The forests of Clathrariæ and Endogenita (the plants of which, like some of the recent arborescent ferns, probably attained a height of thirty or forty feet), must have borne a much greater resemblance to those of tropical regions, than to any that now occur in temperate climates. That the soil was of a sandy nature on the hills and less elevated parts of the country, and argillaceous in the plains and marshes, may be inferred from the vegetable remains, and from the nature of the substances in which they are inclosed. Sand and clay every where prevail in the Hastings strata; nor is it unworthy of remark, that the recent vegetables to which the fossil plants bear the greatest analogy, affect soils of this description. If we attempt to pourtray the animals of this ancient country, our description will partake more of the character of romance, than of a legitimate deduction from established facts. Turtles of various kinds must have been seen on the banks of its rivers or lakes, and groups of enormous crocodiles basking in the fens and shallows.

"The gigantic Megalosaurus, and yet more gigantic Iguanodon, to whom the groves of palms and arborescent ferns would be mere beds of reeds, must have been of such prodigious magnitude, that the existing animal creation presents us with no fit objects of comparison. Imagine an animal of the lizard tribe, three or four times as large as the largest crocodile, having jaws equal in size to the incisors of the rhinoceros, and crested with horns; such a creature must have been the Iguanodon. Nor were the inhabitants of the waters much less wonderful; witness the Plesiosaurus, which only required wings to be a flying dragon; the fishes resembling Siluri, Balista,"

&c.

3. Mathematical and Astronomical Tables for the use of Students of Mathematics, Practical Astronomers, Surveyors, Engineers, and Navigators. By WILLIAM GALBRAITH, M. A. Oliver & Boyd, Edinburgh. 9s.

THIS portable and cheap volume is well worthy of the attention of the practical men alluded to in the title page, and we have no doubt, that, when its merits come to be sufficiently known, it will supersede the use of every other with which we are acquainted. It is needless to mention, that Mr Galbraith gives all the ordinary tables to be found in works with similar objects, such as the logarithms of numbers, logarithmic sines and tangents, and others, without which no surveyor, seaman, or astronomer, can advance a step; and we shall confine ourselves in this notice to an enumeration of such additions and improvements as Mr Galbraith has made, and which we think claim for his work, as we have said above, the notice of all men who are really at work on such subjects.

In the first place, we consider that Mr Galbraith has great merit for giving, in a clear, well ordered, and perfectly scientific style, such a course of demonstrative reasoning on the theory as well as the practice of his subject, as cannot fail to be very useful to students who have a real wish to understand what they are about, and whose better taste and judgment have heretofore been offended by these epitomes which, to use their slang phrase, have been reduced to the lowest capacity. The various methods of obtaining the longitude, are discussed at some length, and with singular clearness. We are not aware that in any other work of this elementary nature, those minute corrections in the lunar method are given; and, in fact, we suspect few navigators are aware of their importance. We allude to the equations for second differences in the distances, which are correctly given only for every 3 hours in the Nautical Almanac, but which are not found in strictness, for an intermediate period, by simple arithmetical proportion. This equation, in some cases, amounts to 6 seconds of distance, 12 seconds of time, or 3 minutes of longitude. Mr Galbraith has computed two little tables for obtaining the proper correction (Introduction, page 102.) Another small correction on account of the oblique semidiameter, is found in two tables by Dr Young, given at page 101. And a table is given by Mr

1

Henderson of Edinburgh, for another correction still, namely, that arising from the effect on the horizontal parallax of the moon, caused by the oblate figure of the earth. We recommend Mr Galbraith, in his next edition, to bring all these corrections distinctly under the reader's view at one place.

Our author does not confine himself, however, to the problems in ordinary use, such as lunar observations, occultations of the fixed stars, chronometrical observations, and the measurement of heights by the barometer, which last is admirably executed, but enters also with the full spirit of an observer, and all the minute accuracy of a computer, into the elegant disquisitions dependent upon the figure of the earth, the velocity of sound, and other topics of high interest.

We shall now proceed to point out briefly those improvements and additions which we have been most struck with in the tables.

In Table II. of the common logarithms, there are added proportional parts, which greatly facilitate its use.

Table V. or logarithmic tangents, &c. has two sets of arguments, one for time, and one for arc, besides proportional parts for seconds at the bottom.

We are decidedly of opinion, however, that, for most practical purposes, it is infinitely better to have separate tables for converting time into arc, and the reverse; and we have reason to believe, accordingly, that Mr Galbraith stopped the press to give tables LXI. and LXII. at our suggestion. In the next edition we hope he will place these two tables by the side of XXX. and XXXI., for converting solar into siderial time, and the reverse, and near XXXII. for converting mean time into parts of the equator. These are all emiuently useful; and we are glad to observe Mr Galbraith giving them at full length, to single seconds, and not in the usual abbreviated shape, which is very teazing.

Tables VI. and VII., for natural sines, tangents, &c. are too contracted, being given to degrees only; if given at all they should be to minutes.

Table IX., for taking out the proportional parts fo ferences of declination, right ascension, &c. we do not as it requires the use of the proportional logarithm JANUARY-MARCH 1827.