however well he might remember the text-book definition, who is unable to recognize and interpret geological phenomena in nature,—in the field and laboratory. Hence, in teaching geology, the mere ability to talk about geology, to say that Paradoxides is characteristic of the Cambrian, that Ichthyosaurus is a Mesozoic reptile, and a thousand other similar items of geological information, is of little or no practical use unless the student is taught to recognize an unlabelled Paradoxides when he sees it, and would know how to distinguish Cambrian rocks in the field. The subject-matter for the scientific scholar to acquire is found in the things and phenomena named and described, and not in the names or definitions.

In other words, the methods of literary instruction are of but limited value in teaching geology, and although we may begin with these methods, the teacher should not deceive himself with supposing that he is teaching science, or that the student is learning science, unless the lectures and text-book work are supplemented by drill in the laboratory and field. It may seem more dignified to stand up in a lecture-room before a lot of students and read off a lecture on geology, but the best results will come from the tramps and the hammerings in the ravines and railroad cuts and the study of hand specimens in the laboratory.

Our lectures may inspire the students to study, but most of what they learn will come by other methods.

We are obliged to use the lecture method, although not the ideal way of teaching science, on account of the large size of classes in our universities, Quizzes, and these written after every five or six lectures, I find of value in calling out study and thought upon the topics discussed in the lectures, and these I believe should always supplement the lecture for the best results.

In the lecture method there is one danger not met with when a good text-book is made the basis of recitations. Unless the lecturer is on his guard he will forget that his pupils are beginners, and neglect to state the essential details needed for a clear understanding of the topics under discussion. These details, when crowded by the multitude of topics he is tempted to consider, will be omitted by the lecturer because they seem to him so familiar.

To ward against this evil I give references to the pages in

the more common text-books on geology, where the student may study more explicitly the subject lectured upon. I expect, too, that the student, who will acquire any exact knowledge of the science, must give some time both to this kind of book study and to the examination of specimens arranged and labelled specially to illustrate the facts discussed.

Again, it is important to so accentuate the lectures that the grand and important lessons shall not be smothered and quite lost to sight by the innumerable names and definitions and topics with which the lecture is necessarily filled. For I hold that, in teaching a class of ordinary college students general geology, it is far more important to teach them how to treat geological problems, what the grand questions are which the geologist meets, and the right methods of attacking, of thinking about, of interpreting them, than to teach definitions, technical formulas, or lists of associated facts.

The latter are all essential for the real geologist to master, but not in the lecture-room. They must be acquired by patient study of the more exhaustive manuals and original reports, and by actual laboratory and field practice.

The work for the lecturer upon general geology is to clearly present the principles of geology, to illustrate and explain the grand features of the science. He must teach what the science treats about, what and where the problems are exhibited, how they are explained, and what laws underlie the phenomena.

While the student gathers enough to excite his interest and enthusiasm, if possible, the method of stating the facts and theories should be such as to enable him to appreciate what there is to learn, rather than to convey any notion that he is getting from the lectures a knowledge of all the essential facts of geology.

We may be able in our lectures to teach the student the alphabet, so to speak, of the science, or even to teach him how to spell or frame sentences in terms of the geological language. We may succeed in showing him how to investigate and interpret geological problems. But I take it to be of essential importance to impress upon the student that the lectures are but an introduction, that the true place to learn geology is in the field and laboratory, and the true method, that of studying over in detail individual phenomena and facts.

This is not generalizing or popularizing the subject; it is making the lectures a means of scientific training, instead of allowing them to degenerate into a glowing account of the wonders of geology.

Geology may truly be a popular subject, because of the many remarkable events and phenomena it reveals, but it is not the remarkable, the unique, and the impressive facts of geology that are the most instructive.

The awful eruption that throws out lava and ashes from a volcanic vent, or tears off the top of a volcanic cone, is not so direct an illustration of the peculiarity of vulcanism as the little bubbles which puff up the cooling lava and testify to the presence of expansive vapors or gases in association with the molten condition of the rock.

The grand cañons of the plateau district are not so valuable as illustrations of the laws of river erosion as a simple rocky ravine composed of a few strata of alternating hard and soft strata, or even the rill along the roadside after a heavy shower. But, after having once grasped the principles of river erosion, its slowness of action, the smallness of the effect in proportion to the amount of water traversing the gorge, then the cañon does become an impressive illustration of the continuity of geologic dynamics over vast periods of time,-of the immensity of deposition of sediments,-of the grand results effected by the slow elevation of continents,-and it serves to convey some conception of the length of actual time with which the geologist has to deal.

Improvement may be made in the order of presentation of the

topics.

In our standard text-books we frequently find what I may call the scholastic method followed,-a method which proceeds from the announcement of principles, laws, or technical definitions to the descriptions or illustrations of facts from which they have been drawn.

As an illustration the following may be taken from chapter second of Dana's Manual. The subject is lithological geology. First we are given a brief classification of the subject, then the definition of rock; then follow three sections in the following order: Ist, the elements constituting rocks; 2d, the mineral materials constituting rocks; 3d, the kinds of rocks.

For a geologist familiar with the general subject, and as a book of information arranged for ready reference, this is as good an arrangement as could be desired. But when the science is presented for the first time to the student, is this the order in which he must grasp the details of the subject for clear comprehension? I think not.

And why is it unnatural? Because the student is asked to take the results of an analysis before he is presented with the conception of the thing analyzed. He is led to form a synthetic conception of the objects studied, built up of definitions, rather than by analysis to increase his knowledge of the object by viewing it in new relations.

Rocks are at first parts of the earth, and among themselves they first differ in their physical relations of position, structure, form, and composition. The chemical and mineral properties are secondary in order of analysis; and the microscopic appearances presented by separate mineral species constitute a tertiary set of characters.

The teacher should have regard to this order of acquisition, although, after having named and briefly described the terms, they may become for his purposes mere definitive terms with which to describe the more comprehensive laws of the earth's formation.

For this reason there is propriety in uniting physiographic, structural, and dynamical geology as a first division of the general treatment of geology, following with the stratigraphical and palæontological part as a second division.

This plan, substantially, is followed in several of the more widely used text-books, as Phillip's, Credner's, Geikie's, Leconte's, and others.

In determining the order of presentation of the facts for particular cases, I examine the order in which the facts naturally develop in the process of investigation. As a general statement of what this order is, I find it to be from the more conspicuous, the more easily grasped, and the simpler, to the less evident, the intricate, and the fundamental. This same regard to the order of acquisition of ideas is applicable to the methods of illustration. Every teacher of natural history has more or less use for diagrams, but I have thought that blackboard sketches, although crude, made while the explanation is going on, are often more

effective in imparting the information desired than the more finished ready-made diagrams. The value of the blackboard sketch is in the fact that it emphasizes your words, makes them more vivid and expressive; with crayon in hand as you talk, the lines of the sketch become a kind of lineal gesture.

This result is particularly seen when the relations of two or more objects are expressed, or when serial or gradual changes or developments are considered, as in explaining Darwin's theory of the formation of coral reefs and islands, or the structure and growth of a common volcanic cone, or the effects of erosion in cutting through a series of hard and soft stratified rocks, and the relation of dykes to eruptive sheets, to volcanic lava-beds or fissure lava-fields.

All such phenomena are more vividly expressed to the beginner by blackboard sketches than by the more perfect diagram, and the reasons seem to lie in the fact that the student only appreciates the points to which his attention is definitely called; the large number of details expressed in the finished drawing tend to divert his thought from the essential few which are brought specially under consideration.

In teaching palæontology, in comparing genera, in pointing out variations and the relations of one form to another, I find the blackboard a great assistance.

A method specially successful of late in the teaching of biology suggests lines of improvement for the teaching of geology. The method I refer to may be called the exhaustive study of types, and such a book as Huxley's "Crayfish" may illustrate its application.

The secret of the value of this method lies in the process of taking a single object for minute and exhaustive study, examining it in all its several relations,-turning it around and throwing light upon it from every side, until the one thing is thoroughly understood in its every relation. The one object thus becomes a familiar and typical example of all the principles involved in its structure, function, or other relations. Afterwards, the widening of one's knowledge becomes a simple and also a systematic mental noting of likenesses and differences. The knowledge thus acquired, instead of being vague and general, becomes positive and precise.

In applying this method to teaching geology, I select a few