MR. ANSTED'S GEOLOGY
Is a very able work ; well-arranged in its plan, comprehensive in its subjects both principal and subordinate, and scholarly in its treatment. It exhibits, in fact, a remarkable example of the effect to be produced by these characteristics, without scientific or lite- rary originality. In one sense the work is a compilation ; it aims at teaching the elements of geology, and presenting a general view of its latest State: but the arrangement is so novel and so co- herent, the mastery of the whole so complete, and the management of geological science, together with the cognate branches of zoology, &c. so skilful, that though the geologist may find little that is new, he will find a great deal exhibited to him in a way which almost produces the pleasure of novelty. A similar observation may be made upon its style. It is not eloquent ; but the structure of the sentences is so workmanly, the meaning is so transparent, and the -writing so finished, that in the more general parts the effect of elo- quence is often produced. It is probable that a close examiner might detect diffuseness in its clear and elegant fulness; but, considering the elementary object of the author, this is rather a merit. Great con- densation is only fit for strong and mature minds. The tyro must be fed with less essential food ; and Professor ANSTED'S Geology was perhaps originally composed for a King's College class—at least it has something the air of lecture. The title of the work—Geology, Introductory, Descriptive, and Practical—truly characterizes the nature of the plan. The first book contains a brief exposition of the principles of geology, or rather of the history of the earth's formation deducible from geological science. In explaining the technical terms of geology, the things which the words represent are so presented that the writer teaches much of the elements whilst seeming to define terms. The exposition of fossils, and their value in geology, gives rise to an ac- count of the classification of the animal kingdom, with an exposition of CUVIER'S law of the mutual relation of structure to habits, and a survey of the great naturalist's labours in paleontology, or the knowledge of animals that are now extinct. The second book, on descriptive geology, occupies by far the largest portion of the volumes, and contains a successive review of the whole of the geo- logical formation of rocks stratified or unstratified, with elaborate accounts of the fossils found in the stratified series. In this review Mr. ANSTED pursues a new method. He neither begins, as is usual, with the uppermost or latest-formed strata and then descends gradually to the oldest, nor does he first take up the unstratified rocks, which, whatever their age, (having been reduced to their present condition by the action of tire,) form in some sense the base of the whole series, as they are the simplest in substance. Our expositor, on the contrary, commences with the earliest series of the palscozoic rocks, or the strata containing the fossil remains of the earliest-formed animals, and then gradually proceeds upwards to the last formation of the tertiary period, and the superficial de- posits of a still later time, treating the unstratified or more simple series last. By this means, he is enabled to proceed on a more natural plan, and to narrate the annals of creation in (so far as we can know) chronological order.
The third book exhibits the application of geology to the prac- tical pursuits of mining, engineering, architecture, agriculture, and so forth. As this division has more direct utility, and will come more home to the "business and bosoms" of many, it may be said to he the most attractive part of the volumes. We think, however, that it is often rather too general in its character ; it wears too much the air of bookish theory. It is always just enough, but not always full and satisfying.
In this estimate of the work, it must be borne in mind that it is geological. A person knowing nothing of the science, and not wishing to learn, would not feel much interest in the expositions however lucid they may be ; nor can Mr. ANSTED, amidst the uncouth terms and dry matter of the more abstruse parts of the science, endow his composition with any other quality than clear- ness to those who wish to study it. Of his more general treatment an idea may be conveyed by a few examples.
NATURAL PREPARATIONS.
In a word, there is no limit to the number and variety of these remains of animal and vegetable existence. At one time we see before us, extracted from a solid mass of rock, a model of the softest, most delicate, and least easily pre- served parts of animal structure ; at another time the actual bones, teeth, and scales, scarcely altered from their condition in the living animal. The very skin' the eye, the foot-prints of the creature in the mud, and the food that it was digesting at the time of its death, together with those portions that had been separated by the digestive organs as containing no further nutriment, are all as clearly exhibited as if death had within a few hours performed its core- mission, and all had been instantly prepared for our investigation. We find the remains of fish, so perfect that not one bone, not one scale, is out of place or wasting; and others, in the same bed, presenting only the outline of a ske- leton, or various disjointed fragments. We have insects, the delicate nervures of whose wings are permanently impressed upon the stone in which they are embedded ; and we see occasionally shells, not merely retaining their shape, but perpetuating their very colours—the most fleeting, one would think, of all characteristics; and offering evidence of the brilliancy and beauty of creation at a time when man was not yet an inhabitant of the earth, and there seemed no one to appreciate beauties which we are perhaps too apt to think were called into existence only for our admiration.
IMPORTANCE OF TEETH.
The form of the teeth, and the corresponding articulation of the jaw, must in a great measure determine the nature of the food which the animal eats; as, for instance, sharp teeth which meet and lock into each other like scissors, with a vertical motion, are only adapted to cut and tear flesh. Animals tlIk■ prov!ded with such organs, on the other band, and whose teeth are flat-topped, and their jaws provided with a lateral motion, could not exist at all if their ex- tremities were not organized so as to obtain a sufficient supply of vegetable food, and their stomachs to digest it. There are several modifications in the structure of the teeth and the motion of the jaw upon which important dis- tinctions are founded : and it has been discovered that even differences so mi- nute that they can only be observed by the aid of an excellent microscope, cor- respond in a most remarkable way to other differences, either in structure or in the habits of the animal; and may be depended on as indicating such differ- ences, even in the absence of every other part of the skeleton.
EGYPTIAN SCIENCE OR ART.
No dependence can ever be placed on a building of which the foundations are not laid on thoroughly-drained ground ; but a very ingenious method has been lately adopted of avoiding the evils of a slippery clay foundation, by cut- ting a large trench below the substructure of a building and tilling it in with sand well rammed. It is found that, when courses of stone are laid uu such a basis, no settlement takes place ; and it appears that this method has been success- fully practised in some of the ancient buildings of Egypt.
A CUNNING TEST.
I have been told by a practical man, who had been employed in selecting stone for an important public building about to be erected, that in looking out for good stone, he was accustomed to go to the churcliyanl in the neighbour- hood of the quarries he wished to judge of, and examine on all sides the oldest
tombstones that were there. He found that he could determine by that means the relative value and durability of most of the stones in the neighbourhood, because they were there exposed under almost all conceivable circumstances. A laminated stone, however, that might he extremely decomposable as a tomb- stone, would not necessarily be bad in the wall of a building, where its edges only are exposed.
'rho volumes are got up with all the well-known taste of the publisher, Mr. Vex VOORST; and are profusely illustrated, the dia- grams and the wood-cuts intermixed with the letterpress being highly useful in explaining the text. The tailpieces have a rela- tion to the chapter they close, but are rather effective ornaments than geologically illustrative.
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