B?itish Mineralogy, 331 



No wonder, therefore, that the penological nomenclature in 

 present use is both indefinite and unintelligible, and, in short, 

 altogether inadequate to the demands of the more advanced state 

 of the other branches of geological inquiry, and, as a conse- 

 quence thereof, that in geological surveys and maps it is common 

 to find eruptive rocks of totally distinct mineral and chemical 

 composition and age confounded with one another (as, for ex- 

 ample, young diorites with old granites, young dolerites with old 

 diabases, &c), and in other cases to find rocks coloured and de- 

 scribed by names which do not pertain to them (called, for ex- 

 ample, syenites when quartz may not be even an essential con- 

 stituent, diorites or greenstones yet not contain hornblende, tal- 

 cose slates without talc, &c). In fact the present state of clas- 

 sification and nomenclature of the eruptive rocks is such that it 

 becomes quite impossible to know with any certainty what exact 

 rock may be intended or mapped under the names generally 

 in use. 



Even in these days of intellectual progress, the old saying that 

 " there is no royal road to learning " remains just as true as ever, 

 and the discovery has not yet been made which would enable the 

 child to read before first mastering the alphabet. 



So even in geology ; for however distasteful and laborious the 

 task may be, it is nevertheless equally essential that the elements 

 of mineralogy (physical and chemical) be acquired before the 

 geologist is entitled to indulge in theoretical generalizations 

 which, it will not even be disputed, must, from their very nature, 

 be based upon such premises. 



Mineralogy appears too often to be confounded with mere 

 crystallography, a branch of applied mathematics undoubtedly 

 of great service in the determination of crystallized mineral 

 species, but which at the same time, especially when studied into 

 its refinements, must be regarded more as of theoretical interest 

 than of practical utility in extending our knowledge of the mi- 

 neral constitution of the globe on which we live. 



It must not be forgotten, therefore, that the study of minera- 

 logy is not confined to the mere dry enumeration of mineral species, 

 along with a description of their physical characters and chemical 

 composition, which unfortunately is too often the entire substance 

 of most text-books on mineralogy in general use, to the exclusion 

 of any information calculated to elucidate the application of these 

 data to the sciences of the geologist and miner, or to assist them 

 in the discrimination and study of rock-masses in the field, and 

 in the investigation of the occurrence and formation of those 

 mineral veins and deposits which, when considered from an eco- 

 nomical point of view, are cf so immense an importance to the 

 progress and welfare of the world in general. 



Z2 



