336 WHITMAN CROSS 
the mineral kingdom—mineralogy, stratigraphic geology, and 
petrography. But while a complete review of the subject must 
note the origin and application of the ideas by which this differ- 
entiation was brought about, it is more particularly the object 
of this retrospect to trace the development of classification, 
beginning with the time when it was first sought to distinguish 
a group of objects even approximately corresponding to rocks 
as at present understood. A brief consideration of the earlier 
stages is, however, necessary to a clear understanding of the 
conditions existing in the first decade of this century. 
Linneus.— Certain gems and ornamental stones were known 
to the ancients by names which they bear to this day; but no 
attempted classification of the mineral kingdom prior to the 
time of Linnzus, in the middle of the eighteenth century, need 
be considered at this time, nor is the system of Linnzus of 
much importance except for the framework of the classification 
he proposed for the mineral kingdom, the same which he applied 
with so much greater success to the organic world. It has been 
said of Linneus that he had a talent amounting to a genius for 
the arrangement of natural objects according to system; that 
“Te founds biology a-chaos; he left it a cosmosy) sBut she 
extended his Systema Nature to cover the inorganic world from a 
logical desire to reorganize the entire field of natural history, 
rather than from an intelligent knowledge of rocks and minerals. 
In the Linnean system the first grand division of the mineral 
kingdom is into Petre, Minera, and Fossilia; but an examina- 
tion of the substances arranged under these heads shows that 
the system expresses great ignorance as to the character and 
relations of many objects classified. Doubtless the followers of 
Linneus, who were many and enthusiastic, were stimulated to 
much research as to the character of rocks and minerals, in 
their efforts to arrange them within the system of their master; 
but the most visible effect of the Linnean system was to furnish 
a theme for controversial debate and argument for a century to 
come. The attempt to force inorganic substances into the same 
scheme of species, genera, etc., provided for plants and animals 
