THE SCIENCE OF OBSERVATION. 459 



attacked from the standpoint of the geologist or physical geographer, 

 or both. 



One of the most pronounced departures taking place in prepara- 

 tory-school education at the present time is to be found in the promi- 

 nence given to these subjects, not only in the schoolroom, but by prac- 

 tical experience in the laboratory of Nature, among the hills and 

 mountains, as well. The object of this departure is twofold: the first 

 and most imoprtant is to train the young early to observe phenomena 

 and to interpret them; the second, in a narrower sense, is purely 

 educational. The one inculcates a habit of thought that will be of 

 inestimable advantage in pursuing future study; the other, without 

 taking into consideration the element of mental training, constitutes 

 instruction in concrete things that are matters of general education. 



Before the student in the introductory schools is brought in con- 

 tact with problems in the field, it is essential that he receive text- 

 book or oral instruction in some of the geological processes giving 

 rise to the phenomena to be studied later out of doors. In practical 

 teaching the student is taken on excursions into the region not far 

 removed from the school. At first some simple geological facts are 

 shown him, often on a very small scale, but embodying principles 

 which, when understood, lead to a ready interpretation of larger 

 problems. Step by step the first principles are amplified by a larger 

 and more varied class of examples, until the student is able logically 

 to apply the reasoning in explanation of simple problems to the solu- 

 tion of the greater problems in physical geography and geology. In 

 the absence of such excursions, I shall introduce a series of photo- 

 graphs carefully arranged to lead the reader along the same line of 

 reasoning up to similar broad conclusions — a method which, if not 

 so satisfactory and instructive, will at least have an educative value. 



Our first excursion will be to a locality where an open cut has 

 been made for the purpose of carrying on quarrying operations. The 

 accompanying photograph has been so taken as to include both the 

 top and the bottom of the quarry (Fig. 1). Let us first inspect the 

 rock in the lower part of the quarry. The existence of planes of 

 fracture, or joints, crossing the rock in various directions, dividing 

 it into blocks, early attracts our attention. The stone appears dark- 

 colored, tough, and is seen to be made up of two or three different 

 minerals: one is black, cleaves readily into thin plates of a translu- 

 cent nature, and we easily recognize it as an iron-bearing mica, or 

 isinglass. Another is white, and cleaves or breaks in two directions, 

 making angles of about ninety degrees; this we know as common 

 feldspar. The third is less easily recognized as pyroxene, another 

 of the many minerals containing iron. Having tested our knowl- 

 edge of mineralogy, we will look about and see if all the rock ex- 



