various parts of Scotland. 411 



the essential distinction of those rocks. I read in the exposition of 

 the Wernerian system best known to us, that " transition hmestone 

 contains petrifactions of marine animals, '* and " that it rests imme- 

 diately on newer clay slate," and in the numerous distinctions assem- 

 bled for the purpose of defining it, these are the only two which 

 appear capable of being rendered truly definitive. Certainly neither 

 of those characters is found in this limestone. Equal difficulties op- 

 pose its admission among xSxQficet'z rocks, when we consider its con- 

 nection with the quartz rock, which, whatever division it may be 

 referred to of the older formations, can scarcely be supposed to 

 belong to this class. Having no anxiety on this head, and con- 

 ceiving that we are still deficient in information, both on the nature 

 of this district, and on the subject at large, I shall willingly leave 

 the determination of its artificial place to those who are either better 

 acquainted with the unwritten laws by which these matters are re- 

 gulated, or to a period of further information. 



To a mere observer, uninfluenced by systems, it exhibits the re- 

 mains of a disposition originally stratified and horizontal, but dis- 

 turbed, inclined, and broken, by subsequent changes ; — a disposi- 

 tion, which however uniform in more distant times, has been 

 altered to its present one with a partial, not a total loss of its 

 original character, by revolutions of which the antiquity and mag- 

 nitude are unknown to us, and by agencies which we are ill able to 

 explain. Any system of arrangement may be useful, which, al- 

 though artificial, assists us in classing and describing phenomena 

 more satisfactorily; but if we are to adopt the system of arrangement 

 to which I have alluded above, it is much to be desired that geolo- 

 gists would furnish us with such characters as shall enable us to 

 decide on the different bodies appertaining to the several divisions 

 of their system, without which, an artificial arrangement is not 



3 F 2 



