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Now, whenever a geologist sees the results of some great force and those results are similar to the phenomena produced by glaciers, he concludes that at some previous time the conditions were such as to make it possible for glaciers to exist in the locality in which his observations were made, for no other force could produce them.

2 He reasons that all affects must be referred to secondary causes. In other words, law governs all phenomena, and forces are so balanced as to produce all known and unknown phenomena. All events that have transpired in the development and configuration of the earth have been brought about by law. In the formation of glaciers certain laws are obeyed, and those laws are always obeyed unless an equilibrium is sustained between them and some other laws are overbalanced.

When the conditions are favorable for the action of glacial laws glaciers will be found. The same principle holds good, in the distribution of life.

3. The forces in existence to-day are capable of producing all phenomena that have and may occur. Therefore, the geologist · must study the methods by which they are producing changes at present, and thereby be able to judge of what took place ages ago, and the manner in which great events transpired. In other words, the past is understood by the present . and to some extent the future may also be understood. No new law is, nor has been, necessary for the explanation of phenomena and, therefore, there have been no accidental happenings. There may be laws that man has not as yet learned the nature of, and they may be so balanced as to be beyond man's comprehension, but that there are being or have been created new laws, and that there are accidents, the geologist does not admit.

4. The earth is undergoing and therefore has undergone changes. He sees this in studying the phenomena of denudation and disintegration. He sees that the mountains are being destroyed by chemical and physical agencies, and that they are being gradually carried into the valleys, and then into the sea. This, he reasons, must have been going on ever since the first continent made its apppearance.

5. Finally, from a consideration of the above principles, the geologist realizes that his work must be systematic, and that the bulk of it must be done in the field. Field investigation is indispensable. Laboratary work holds a subordinate position.

It is safe to say that geology has advanced more rapidly. than any other science, and the number of those who are making a specialty is steadily growing. New periodicals devoted to the science are continually appearing, and its literature is quite comprehensive. Very little attention was paid to it in our colleges at no late date, but to-day it occupies a prominent position.

The great advance which has been made is due to systematic field work, followed by laboratory work, and the latter is of but little value from a geological standpoint unless it is based upon accurate field investigation. It is necessary to reduce to a practical formula the data secured in the field, and to have a definite method of procedure, for without such, much time is wasted, and many results that otherwise would have been valuable are entirely lost. Mere conjecture must not be indulged in, but“ work persistently back from the seen and known to the unseen and unknown,” should be the maxim. Conclusions must not be arrived at too hastily. Professor Dana once said, “I think it better to doubt until

Too many people assert, and then let others doubt." Hence, in drawing conclusions from the results of field and laboratory work, be sure you are right, before giving publicity to them, and if a doubt exists, state it, and be willing to change your theory.

“I always like to change when I can make a change for the better."

It is obvious, from what I have said, that geology is a field science. Different characteristics of the earth's surface cannot always be taken into the laboratory for study at leisure, and it is necessary to see the objects under study if we would arrive at correct conclusions and fix them indelibly in our minds. Facts then become real, and we acquire a correct understanding in regard to the forces that have been at work preparing this planet for man.

you know

Dana says,

It is necessary to have a knowledge of other sciences if one would make practical use of geology, that is, to understand the many phenomena that are presented to him.

Natural philosophy and chemistry are necessary in order to determine the composition of rocks and to understand how they were formed and changed. Botany is necessary to understand paleobotany, zoology is necessary to understand paleozoology, astronomy figures very prominently in the determination of the relations of this planet to other heavenly bodies. Anything that the telescope and the spectroscope reveal is of geological importance, and bears upon the past and future condition of the earth. Mathematics is constantly in use, and without that science little or nothing could be accomplished.

The foundation work of a geologist, therefore, should be a knowledge of the natural sciences, for without them he will be materially hampered in his work. Geology is practical as well as literary in nature.

Every agriculturalist would become more scientific, and would reap better "crops” if he had a knowledge of the science, for it gives a knowledge of soils and fertilizers. To the engineer it is of great importance, for thereby he understands drainage and the best methods for excavating. It is of great importance to the manufacturer, for he can better understand clays, ores, fuels, etc., and in mining it is of great value for it enables the miner to understand the nature of the rock in which the metals occur and assists him in “prospecting."

This use of the science is termed “ Economic Geology” and is of inestimable value and importance in developing systematically the resources of a state or of a nation.

The United States government has realized the importance of thorough and accurate investigation of this vast country of ours from an economic standpoint, and established the U.S. Geo. Survey in 1879 for this purpose. Most of the states have their surveys and work for the same ends, but on a smaller scale, and assist, and are assisted by, the government survey, and so work in harmony with each other.

Individuals are at work gathering information in regard to particular formations, correcting mistakes, advancing new theories, devising new plans for more thorough and accurate works and imbuing students with the grandeur of the science.

What is there more sublime than a science that reveals the universe in all its beauty and grandeur and as the result of the balancing of forces which emanate from a creative will ? Geology reviews the history of the planet from the earliest known formation to the present.

Back of this it goes by retrograde calculation, and hence we have a complete resumé from the time “the earth was without form and void,” to the phenomena observed to-day. It tells us of periods of time of immeasurable duration, during which was being molded that upon which it would be possible for life to exist, and over which mind should rule.

There is no science which presents so many problems to be studied, nor in which so much of interest can be taken. It carries one over plains, up the rugged mountains and down into valleys. On every hand is found something new upon which to concentrate the mind, and which demands a satisfactory explanation. How came these plains, these mountains, these valleys? How came those masses of rock, thousands of feet high? Why is sandstone here, limestone there, and granite yonder? What mean those remains of animals and plants that are not in existence to-day? Why are those masses of rock in every conceivable position? Whence came the waters and the land ? The plants and animals? Is there a reason for all we see ? Are these things accidental, or was there a purpose in their formation ?

And so questions crowd upon us, and fill us with wonder and admiration, and with a determination not to be satisfied until they are answered. We see that law is at work, fashioning the universe, and we have brought very forcibly to our minds the fact that there was a purpose involved in the creation of the universe, and that from this realized grand conception is being evolved a divine purpose. That which at first appeared to be outside the domain of law, is seen to be the result of the balancing of forces; and we come to realize the fact

that law pervades the universe, and although we do not know as yet the way in which these laws are balanced to produce all phenomena, that they are so balanced as to produce harmony, and that in proportion as the human mind develops it will be capable of grappling with problems that are not now within its reach.



(Continued from page 188.) Such a new stage of existence may have been essayed frequently. The dwellers in the early seas, in their descents below the surface, must often have come into contact with the bottom, and at times temporarily rested upon it. This contact with hard substance doubtless produced some effect upon them, and certain variations in structure may have proved of advantage in these new circumstances and been retained and further developed. Particularly if food was found there, and habitation on or near the bottom was thus encouraged, would such favoring variations tend to be preserved.

But, as has been said, myriads of years may have passed in the slow development of swimming pelagic animals before this phase of evolution was completed. And, perhaps, not until this was fully accomplished did contact with the bottom set in train a new series of changes, and in time give rise to the greatly transformed bottom-dwellers. The change, indeed, Was a great one, if we may judge by the wide diversity in character between the swimming embryos and the mature forms of oceanic invertebrates, and must have needed a long period of contact with the bottom for its completion. Yet it was probably much more rapid than had been the preceding pelagic development.

Contact with solid substance was a decided change in condition, and may have greatly increased

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