Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/421

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various parts of Scotland.

the essential distinction of those rocks. I read in the exposition of the Wernerian system best known to us, that "transition limestone contains petrifaction's of marine animals," and "that it rests immediately on newer clay slate," and in the numerous distinctions assembled 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 oppose its admission among the flœtz rocks, when we consider its connection 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 conceiving 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 regulated, or to a period of further information.

To a mere observer, uninfluenced by systems, it exhibits the remains of a disposition originally stratified and horizontal, but disturbed, inclined, and broken, by subsequent changes;—a disposition, 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 magnitude are unknown to us, and by agencies which we are ill able to explain. Any system of arrangement may be useful, which, although 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 geologists 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

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