D 
ontologists; why the geologists of Pennsylvania have taught u 
so much about stratigraphy and the structure and products below 
the surface. 
In each institution the natural advantages found in the acces- 
sible rock exposures of the region should be not only carefully 
‘studied, but should be made a prominent feature in all the 
advanced work of the college. 3 
In conclusion, I would remark that (a) the fundamental natu 
of the subject-matter of geology, with its many still unsolved 
~ 626 Methods of Instruction in General Geology. 
the evident, the general, to the special, the hidden, the individua 
tion from the concrete, the typical, the illustrative, to the princ 
and accuracy in his modes of nd cf by applying the simp! 
; rule of teaching much about a few things, instead of arenes 
ie to say a little about a great many things, 
