108 Prof. Sedgwick and Mr. Murchison on the 



nummulite-limestone, apparently subordinate to great beds of 

 indurated marl resembling planer-kalk. The geological rela- 

 tions at the last-mentioned places are rather obscure; but the 

 deposits are we think unquestionably secondary, and nearly 

 on the same parallel with those at Sonthofen. 



On the whole we concluded, that the different portions of 

 the ridges above described, which appear on the outskirts of 

 the Alps, were nearly of the same age with the green-sand 

 and chalk formations of England. The conclusion seems to 

 be borne out by the position of the subordinate beds, as well 

 as by their fossils, and is in some instances also confirmed by 

 their mineral contents. 



It was our wish in this sketch of the structure of the East- 

 ern Alps, to avoid mere matters of detail, as being incompa- 

 tible with our object. But the short abstracts of some of our 

 former communications having been misunderstood, and con- 

 sequently misrepresented ; it became necessary, in this account 

 of the younger Alpine limestone, to explain our views, more 

 at length than we first intended, by referring to two or three 

 specific localities. 



7. Tertiary Deposits*. 



Having in two papers, read last year before the Geological 

 Society, explained our views respecting the tertiary deposits 

 of the Austrian Alps ; we should not have added anything to 

 what we have already stated, had it not been necessary to 

 notice certain comments on these communications which have 

 been published by Dr. Boue f. 



1. He is mistaken in supposing that we confounded the iron 

 sand of Sonthofen with rocks of the tertiary age. We dis- 

 tinctly stated that it contained Ammonites and Belemnites, and 

 alternated with beds of the younger Alpine limestone ; from 

 which we concluded that it was secondary; and this con- 

 clusion is given, though very shortly, in the published abstract 

 of our paper (Phil. Mag. and Annals, N.S. vol. vii. p. 53). On 

 the age of the Sonthofen beds there appears therefore to be no 

 difference of opinion between ourselves and Dr. Boue: but he 

 has been led to misrepresent our meaning, from knowing no- 

 thing of our communications except through the medium of 

 abstracts, which from their brevity may be easily misunder- 

 stood. 



* By tertiary deposits we mean all regular beds, of whatever age, newer 

 than the chalk. 



f See New Edinburgh Philosophical Journal, Jan. 1830, p. 176; Bul- 

 letin cles Sciences, Fevrier 1830, p. 228— Jjiin 1829, p. 328 ; Abstract of the 

 Proceedings of the Geological Society (Phil. Mag. and Annals of Philosophy, 

 for the last month, p. 64-67), &c. 



2. Pie 



