200 BERTHA^S VISIT TO HER 



u The fifth, and lowest, contains all the varie 

 ties of granite and gneiss. 



" These five series, or orders, ha\ 7 e been named 

 by one of our best geological writers, superior, 

 super-medial, medial, submedial, and inferior. 

 But the most general relation under which all 

 these minerals present themselves, is that from 

 which they have been named primitive and 

 secondary. The primitive comprehend the 

 lowest series of rocks, which serve as the bases 

 upon which the others rest. They never con- 

 tain any traces of former animals or vegetables, 

 and may be supposed to have constituted the 

 materials of the earth's original surface. 



" On the other hand, the different series which 

 cover them, sometimes contain the remains of 

 vegetables and animals imbedded in them ; or 

 sometimes they are made up of broken fragments 

 of the primitive rocks, cemented together in a new 

 form ; and these are therefore considered to be 

 of a subsequent and secondary origin. Geologists, 

 however, having observed that between the 

 primitive rocks, and those which exhibit most 

 distinctly the characters of the secondary class, 

 there are others partaking of the nature of both, 

 and containing comparatively but few organic 

 remains, have distinguished them by the title of 

 transition rocks. And the rocks which are 

 above this transition series, they call floelz rocks ; 

 a German term, implying their having been 



