geology-books

"I was influenced by my experience of the limited acquaintance with the historical development of the science which has often been shown, even by those who have done good service in enlarging its boundaries. English-speaking geologists have for the most part contented themselves with the excellent, but necessarily brief, summary of the subject given by Lyell in the introductory chapters of his classic Principles, no fuller digest of geological history having been published in their language."

"It appeared to me that it might be useful to recount the story of a few of the great pioneers during the momentous period... and to show, from their struggles, their failures, and their successes, how geological ideas and theories arose, and were step by step worked out into the forms they now wear."

"In order to trace the history of... petrographical resuscitation we must... transport ourselves to the workshop of an ingenious and inventive mechanician, William Nicol... Among his inventions was the famous prism of Iceland spar that bears his name. Every petrographer will acknowledge how indispensable this little piece of apparatus is in his microscopic investigations. ...it was the same skillful hands that devised the process of making thin slices of minerals and rocks, whereby the microscopic examination of these substances has become possible."

"Nicol hit upon the plan of cutting sections of fossil wood, so as to reveal its minutest vegetable structures. He took a slice from the specimen to be studied, ground it perfectly flat, polished it, and cemented it by means of Canada balsam to a piece of plate-glass. The exposed surface of the slice was then ground down, until the piece of stone was reduced to a thin pellicle adhering to the glass, and the requisite degree of transparency was obtained. Many of these were described by Henry Witham in his Observations of Fossil Vegetables (1831)."

"I am afraid that the geologists are about as difficult to move as their own erratic blocks. They took no notice of the possibilities put in their way by William Nicol."

"When Nicol died, his instruments and preparations passed into the hands of the late Mr. Alexander Bryson of Edinburgh, who... made many additions to the collections which he had acquired. In particluar, he made numerous thin slices of minerals and rocks for the purpose of exhibiting the cavities containing fluid, which had been described long before by David Brewster and Nicol."

"At last Mr. Henry Clifton Sorby came to Edinburgh, and...was particularly struck with the series of slices illustrating "fluid cavities," and at once saw that the subject was one of which the further prosecution could not fail to "lead to important conclusions in geological theory." He soon... made sections of mica-schist, and... threw his whole energy into the investigation for several years, and produced at last in 1858 the well-known memoir, On the Microscopical Structure of Crystals, which marks one of the most prominent epochs of modern geology."

"William Nicol was never adequately recognised in his lifetime."

"Sorby... for the first time, showed how, by means of a microscope, it was possible to discover the minute structure and composition of rocks, and to learn much regarding their mode of origin. He took us... into the depths of a volcanic focus, and revealed the manner in which lavas acquire their characters. He carried us still deeper into the terrestrial crust, and laid open the secrets of those profound abysses in which granitic rocks have been prepared."

"The reproach that it was impossible to look at a mountain through a microscope was brought forward in opposition to the new departure which he [Sorby] advocated. Well did he reply by anticipation to this objection. "Some geologists, only to examine large masses in the field, may perhaps be disposed to question the value of the facts I have described, and to think the objects so minute as to be quite beneath their notice, and that all attempts at accurate calculations from such small data are quite inadmissible. What other science, however, has prospered by proposing such a creed? ...I ague that there is no necessary connection between the size of an object and the value of the fact, and that, though the objects I describe are minute, the conclusions to be derived from the facts are great.""

"From the beginning of its career, geology has owed its foundation and its advance to no select and privileged class. ...No branch of natural knowledge lies more invitingly open to every student who, loving the fresh face of Nature, is willing to train his faculty of observation in the field, and to discipline his mind by the patient correlation of facts and the fearless dissection of theories."

"The history of geological science presents some conspicuous examples of the length of time that may elapse before a fecund idea comes to germinate and bear fruit. Consider for a moment how many years passed before the stratigraphical conceptions of [G.C.] Füchsel, Lehmann, and [the Abbé, Jean-Louis] Giraud-Soulavie took more definite shape in the detailed investigations of Cuvier, Brongniart and Smith, and how many more years were needed before the Secondary and Tertiary formations were definitely arranged and subdivided as they now stand in out tables. ...even after the principles of stratigraphy had been settled, a quarter of a century had slipped away before they were successfully applied to the Transition rocks, and a still longer time before the system of zonal classification was elaborated."

"Note how long the controversy lasted over the origin of basalt, and how slowly came the recognition of volcanic action as a normal part of terrestrial energy... Mark also, in the history of physiographical geology, that though the principles of this branch of science were in large measure grasped by Desmarest, De Saussure and Hutton in the eighteenth century, their work was neglected and forgotten until the whole subject has been revived amd marvellously extended in our own day."

"How slowly the key that now unlocks the innermost mysteries of rock-structure was made use of. Five and twenty years after William Nicol had shown how stony substances could be investigated by means of the microscope, before Mr. Sorby called the attention of geologists to the enormous value of the method thus put into their hands."

"We are warned to be on the lookout for the unrecognized meanings and applications in the work of our own day and in that of older date. We are taught the necessity not only of keeping ourselves abreast of the progress of science at the present time, but also of making ourselves acquainted as far as we possibly can with the labours of our predecessors."

"...the permanent vitality of truth. The seed may be long in showing signs of life, but these signs come at last."

"In the case of geological literature, a large mass of the writing of the present time is of little or no value for any of the higher purposes of the science, and... it may quite safely and profitably, both as regards time and temper, be left unread."

"If geologists... could only be brought to realise that the addition of another paper to the swollen flood of our scientific literature involves a serious responsibility; that no man should publish what is not of real consequence, and that his statements should be as clear and condensed as he can make them, what a blessed change would come over the faces of their readers, and how greatly would they conduce to the real advance of science which they wish to serve!"

"It seems to me that one important lesson to be learnt from a review of the successive stages in the foundation and development of geology is the absolute necessity of avoiding dogmatism. Let us remember how often geological theory has altered. The Catastrophists had it all their own way until the Uniformitarians got the upper hand, only to be in turn displaced by the Evolutionists."

"The Wernerians were as certain of the origin and sequence of rocks as if they been present at the formation of the earth's crust. Yet in a few years their notions and overweening confidence became a laughing-stock."

"What seems to be a well-established deduction in one age may be seen to be more or less erroneous in the next."

"Each of us has it in his power to add to this accumulation of knowledge. Careful and accurate observation is always welcome, and may eventually prove of signal importance."

"While availing ourselves freely of the use of hypothesis as an aid in ascertaining the connection and significance of facts, we must be ever on our guard against premature speculation and theory, clearly distinguishing between what is fact and what may be our own gloss or interpretation of it."

"Let us hold high the torch of science, and pass it on bright and burning to those who shall receive it from our hands."

"We seek to know that operation by means of which masses of loose materials, collected at the bottom of the sea, were raised above its surface, and transformed into solid land."

"The present question is not, what had been the cause of heat, which has appeared to have been produced in that place; but, if this power of heat, which has certainly been exerted at the bottom of the ocean for consolidating strata, had been employed also for another purpose, that is, for raising those strata into the place of land."

"It is a truth unquestionable, that what had been originally at the bottom of the sea, is at present the highest of our land. In explaining this appearance, therefore, no other alternative is left, but either to suppose strata elevated by the power of heat above the level of the present sea, or the surface of the ocean reduced many miles below the height at which it had subsisted during the collection and induration of the land which we inhabit."

"The strata of the globe are actually found in every possible position: For from horizontal, they are frequently found vertical; from continuous, they are broken and separated in every possible direction; and from a plane, they are bent and doubled. It is impossible that they could have originally been formed, by the known laws of nature, in their present state and position; and the power that has been necessarily required for their change, has not been inferior to that which might have been required for their elevation from the place in which they had been formed."

"We are now to conclude, that the land on which we dwell had been elevated from a lower situation by the same agent which had been employed in consolidating the strata, in giving them stability, and preparing them for the purpose of the living world. This agent is matter actuated by extreme heat, and expanded with amazing force. If this has been the case, it will be reasonable to expect, that some of the expanded matter might be found condensed in the bodies which have been heated by that igneous vapour; and that matter, foreign to the strata, may have been thus introduced into the fracture and separations of those indurated masses."

"Lastly, We have a surrounding body of atmosphere, which completes the globe. This vital fluid is no less necessary in the constitution of the world than are the other parts; for there is hardly an operation upon the surface of the earth, that is not conducted or promoted by its means. It is a necessary condition for the sustenance of fire; it is the breath of life to animals; it is at least an instrument in vegetation; and while it contributes to give fertility and health to things that grow, it is employed in preventing noxious effects from such as go into corruption. In short, it is the proper means of circulation for the matter of this world, by raising up the water of the ocean, and pouring it forth upon the surface of the earth."

"To see the evidence of marble, a body that is solid, having been formed of loose materials collected at the bottom of the sea, is not always easy, although it may be made abundantly plain; and to be convinced that this calcareous stone, which calcines so easily in our fires, should have been brought into fusion by subterraneous heat, without suffering calcination, must require a chain of reasoning which every one is not able to attain. But when fire bursts forth from the bottom of the sea, and when the land is heaved up and down, so as to demolish cities in an instant, and split asunder rocks and solid mountains, there is nobody but must see in this a power, which may be sufficient to accomplish every view of nature in erecting land, as it is situated in the place most advantageous for that purpose."

"These operations of the globe, remain at present with undiminished activity, or in the fulness of their power."

"That Sicily itself had been raised from the bottom of the ocean, and that the marble called Sicilian Jasper, had its solidity upon the same principle with the lava, would stumble many a naturalist to acknowledge. Nevertheless, I have in my possession a table of this marble, from which it is demonstrable, that this calcareous stone had flowed, and been in such a state of fusion and fluidity as lava."

"On the 7th of March and 4th of April, 1785, Hutton read to the Royal Society of Edinburgh his Memoir on a "Theory of the Earth ; or an Investigation of the Laws observable in the Composition, Dissolution and Restoration of Land upon the Globe." Extending to no more than 96 quarto pages, it was written in a quiet, logical manner, with no attempt at display but with an apparent anxiety to state the author's opinions as tersely as possible. Probably no man realised then that this essay would afterwards be regarded as marking the turning-point in the history of geology. For some years it remained without attracting notice from friend or foe."

"It does not appear to be generally known that Desmarest, departing from his usual practice of not noticing the work of living writers, wrote a long and careful notice of Hutton's Memoir of 1785 in the first volume of his Géographie Physique, published in 1794-1795. He disagrees with many of Hutton's views, such, for instance, as that of the igneous origin of granite. But he generously insists on the value of the observations with which the Scottish writer had enriched the natural history of the earth and the physical geography of Scotland. "It is to Scotland," he says, "that Hutton's opponent must go to amend his results and substitute for them a more rational explanation.""

"We have but to open our eyes to be convinced of this truth. Look into the sources of our mineral treasures; ask the miner, from whence has come the metal into his vein? ...There is but one place from whence these minerals may have come; this is, the bowels of the earth, the place of power and expansion, the place from whence must have proceeded that intense heat by which loose materials have been consolidated into rocks, as well as that enormous force by which the regular strata have been broken and displaced."

"The surface of this land, inhabited by man, and covered with plants and animals, is made by nature to decay, in dissolving from that hard and compact state in which it is found below the soil; and this soil is necessarily washed away, by the continual circulation of the water, running from the summits of the mountains towards the general receptacle of that fluid."

"Time, which measures every thing in our idea, and is often deficient to our schemes, is to nature endless and as nothing; it cannot limit that by which alone it had existence; and as the natural course of time, which to us seems infinite, cannot be bounded by any operation that may have an end, the progress of things upon this globe, that is, the course of nature, cannot be limited by time, which must proceed in a continual succession. We are, therefore, to consider as inevitable the destruction of our land, so far as effected by those operations which are necessary in the purpose of the globe, considered as a habitable world..."

"In what follows... we are to examine the construction of the present earth, in order to understand the natural operations of time past; to acquire principles, by which we may conclude with regard to the future course of things, or judge of those operations, by which a world, so wisely ordered, goes into decay; and to learn, by what means such a decayed world may be renovated, or the waste of habitable land upon the globe repaired."

"Sand is separated and sized by streams and currents; gravel is formed by the mutual attrition of stones agitated in water; and marly, or argillaceous strata, have been collected, by subsiding in water with which those earthy substances had been floated. Thus, so far as the earth is formed of these materials, that solid body would appear to have been the production of water, winds, and tides."

"The greatest part of the calcareous masses upon this globe... have originated from marine calcareous bodies; for whether we examine marbles, limestones, or such solid masses as are perfectly changed from the state of earth, and are become compact and hard, or whether we examine the soft, earthy, chalky or marly strata, of which so much of this earth is composed, we still find evident proofs, that those beds had their origin from materials deposited at the bottom of the sea; and that they have the calcareous substance which they contain, from the same source as the marbles or the limestones."

"We are led... to conclude, that all the strata of the earth, not only those consisting of such calcareous masses, but others superincumbent upon these, have had their origin at the bottom of the sea, by the collection of sand and gravel, of shells, of coralline and crustaceous bodies, and of earths and clays, variously mixed, or separated and accumulated. ... forming a general rule, which shall comprehend almost the whole, without doing it absolutely. This excluded part consists of certain mountains and masses of granite. These are thought to be still older in their formation, and are very rarely, at least, found superincumbent on strata which must be acknowledged as the productions of the sea."

"All the consolidated masses, of which we now enquire into the cause, are upon the surface of the earth in a state of general decay, although the various natures of those bodies admit of that dissolution in very different degrees."

"The strata formed at the bottom of the sea, are to be considered as having been consolidated, either by aqueous solution and crystallization, or by the effect of heat and fusion."

"Knowing those general laws, and making just observations with regard to the natural appearances of those consolidated masses, a philosopher, in his closet, should be able to determine, what may, and what may not have been transacted in the bowels of the earth, or below the bottom of the ocean."

"We have strata consolidated by calcareous spar a thing perfectly distinguishable from the stalactical concretion of calcareous earth, in consequence of aqueous solution. We have strata made solid by the formation of fluor, a substance not soluble, so far as we know, by water. We have strata consolidated with sulphureous and bituminous substances, which do not correspond to the solution of water. We have strata consolidated with siliceous matter, in a state totally different from that under which it has been observed, on certain occasions, to be deposited by water. We have strata consolidated by feldspar, a substance insoluble in water. We have strata consolidated by almost all the various metallic substances, with their almost endless mixtures and sulphureous compositions; that is to say, we find, perhaps, every different substance introduced into the interstices of strata which had been formed by subsidence at the bottom of the sea."

"Heat is an agent competent for the consolidation of strata which water alone is not."

"There are to be found among the various strata of the globe, bodies formed of two different kinds of substances, siliceous bodies, and those which may be termed sulphureous. With one or other, or both of those two substances, every different consolidated stratum of the globe will be found so intimately mixed, or closely connected, that it must be concluded, by whatever cause those bodies of siliceous and sulphureous matter had been changed from a fluid to a concreted state, the strata must have been similarly affected by the same cause."

"Siliceous matter, physically speaking, is not soluble in water..."

"Here, for example, are crystallized together in one mass, first, Pyrites, containing sulphur, iron, copper; 2dly, Blend, a composition of iron, sulphur, and calamine; 3dly, Galena, consisting of lead and sulphur; 4thly, Marmor metallicum, being the terra ponderosa, saturated with the vitriolic acid; a substance insoluble in water; 5thly, Fluor, a saturation of calcareous earth with a peculiar acid, called the acid of spar, also insoluble in water; 6thly, Calcareous spar, of different kinds, being calcareous earth saturated with fixed air, and something besides, which forms a variety in this substance; lastly, Siliceous substance, or Quartz crystals. All these bodies, each possessing its proper shape, are mixed in such a manner as it would be endless to describe, but which may be expressed in general by saying, that they are mutually contained in, and contain each other."