of Granite and Sandstone in Sutherland. 283 



questionable specimens of sandstone. In fact, where such 

 conglomerates consist of the same materials that constitute 

 the neighbouring granite, as they do in this particular case, 

 and where they are, at the same time, compacted by the crys- 

 tallization of intermediate quartz, while the fragments are 

 small and angular, it is scarcely possible, without great ex- 

 perience, to distinguish them from granite of the same compo- 

 sition. If, as in this case, from being detached, and lying 

 promiscuously on a beach, in company with fragments of 

 granite, no traces of their geological connection remain, 

 while the very circumstance leads to confusion, it is not sur- 

 prising that they should not easily be distinguished. 



We are not, therefore, entitled to conclude that there is a 

 real gradation of mineralogical character, between this granite 

 and the superincumbent sandstone connected with, and de- 

 pendent on their geological proximity, and capable of proving 

 a sequence or continuity of geological formation. The same 

 resemblances take place where no granite is present, and 

 where, from the quantity and nature of the intermediate rocks, 

 it is certain that a great interval of time has elapsed between 

 the formation of the granite and that of the sandstone. 



If these explanations, then, of the probable nature, both of 

 the geological relations, and the mineralogical resemblance of 

 these two rocks, be judged satisfactory, the difficulties arising 

 from the first contemplation of these appearances, vanish, and 

 the whole is reduced to the ordinary laws, by which the rela- 

 tive positions and nature, both of granite and sandstone, have 

 hitherto been supposed, by all rational observers, to be regu- 

 lated. The coincidence alone is the cause of the apparent 

 difficulties ; and that coincidence, as far as their appearances 

 are concerned, is accidental. One useful general lesson is, 

 at any rate, to be deduced from it ; namely, that we should 

 never suffer ourselves to be seduced by the first obvious ap- 

 pearances, which, in this science, as in others, are always 

 ready to mislead us, particularly when they coincide with our 

 vrishes or our prejudices. The philosopher, " naturae mini- 

 ster," has one especial duty to perform, that of recording 

 faithfully the facts which fall under his observation; and it is 

 sdso his business to spare no trouble or thought, in investi- 



