620 — Methods of Instruction in General Geology. oo 
maa 
= This is not generalizing or popularizing the subject; 
making the lectures a means of scientific training, instead 
allowing them to degenerate into a glowing account of tl 
wonders of geology. i 
© Geology may truly be a popular subject, because of t 
many remarkable events and phenomena it reveals, but it is n 
the remarkable, the unique, and the impressive facts of geolog 
that are the most instructive. 
The awful eruption that throws out lava and ashes from 
volcanic vent, or tears” off the top of a volcanic cone, is not 
direct an illustration of the peculiarity of vulcanism as 
little bubbles which puff up the cooling lava and testify to 
presence of expansive vapors or gases in association with | 
molten condition of the rock. 
The grand cajions of the plateau district are not so vale 
as illustrations of the laws of river erosion as a simple rock 
— of the length of actual time with which the — 
has to 
topics. 
` In our standard text-books we frequently find what I maj 
call the scholastic method followed,—a method which proceeds 
tions to the descriptions or illustrations of facts from which th 
have been drawn. oe 
As an illustration the following may be taken from chapt 
second of Dana’s Manual. The subject is lithological geolog 
First we are given a brief classification of the subject, then the 
definition of rock; then follow three sections in the followi 
order: Ist, the elègients constituting rocks; 2d, the mine! 
materials constituting rocks; 3d, the kinds of rocks, 
