^f 



89 



schorl has hitherto been found only h] prhnltive rocks, particularly in 

 granite* and in gneiss, or in veins winch traverse those rocks, whilst 

 it may, occasionally, be observed in mica slate or argillite* These 

 different opinions of eminent men would, if always correct, afford 

 excellent data to reason upon in affixing eras to families of mineral 

 masses, but unfortunately, although they may generally be true on an 

 extended scale in particular localides, they are frequently found to be 

 at variance with existing facts in odiers. 



If such able geologists arc at a loss on the absorbing question of the 

 ages of rocks, it may seem presumptuous for us to offer any asser- 

 tions on a subject so intensely interesting, at a time when geology is 

 still so far from having received more than a glimmering of the true 

 light. Whatever, therefore, may be our preconceived ideas, or how- 

 ever we may have been led to form opinions, either from appear- 

 ances or from reflection, we must hesitate to announce them, and 

 confine ourselves to simple statements of facts ; trusting that when 

 other laborers In the cause shall have outstripped the endeavors of 

 the great modern geologists, and when similar statements from various 

 countries shall have been combined, a Newton may arise, who shall 

 render geology what mathematics is at die present age, a science of 

 reason and of truth. 



■- 



Werner and his school, define transition rocTcs to be those which 

 have a great analogy to tlie primitive class, but which alternate widi 

 the brecciated or arenaceous kinds, whilst ihey contain, in their upper 

 genera, some few remains of organized bodies, the animal fossils be- 

 ing chiefly confined to die tribes of madrepores, pentacrinites, ordio- 

 ceratites, trilobites, &:c. and the vegetable relics to impressions of 

 reeds, palms and gigantic ferns, which are all exhibited, chiefly, in 

 those species of rocks not containing felspar and which are not of a 

 very crystalline aspect- As a broad foundation to work upon in the 

 present state of the science, these data are doubdess very well adapt- 

 ed to the exigencies of the case, although we fear that they will be 

 found at some future period, to be in the same predicament with all 

 other positive assertions regarding die ages of rocks, as we shall 

 presently shew, that testaceous organic relics may be exj)ected to ex- 

 hibit themselves in transidon formadons, where felspar holds the most 



* It exists however in considerable quantities in tlie transili<jn rocks of the St 

 Lawrence and the Cataraqui. 



Vol. XVIII.— No. 1 . 12 



