ARE THEY TERTIARY ? 237 



rnica and especially the talcose schists. Generally the specular and magnetic ores are 

 found in schists that have undergone a more powerful metamorphic action than those 

 underlying the hematites. The inference, therefore, is certainly fair, that whatever rock 

 contains the carbonate of iron especially, and indeed any of the other species of iron, 

 may prove a source of the brown hematite. In some instances, already mentioned, we 

 find the exposed portion of the vein or bed transformed into hematite, but not denuded ; 

 yet in general the disintegrated portion has been more or less swept off by water and 

 re-deposited. Hence we should say that no one rock, but all that contain other ores of iron, 

 especially the carbonate, may have originated the hematite. 



ARE THESE STRATA TERTIARY ? 



But have we sufficient evidence to refer this ore in its present position to the tertiary 

 period ? Certainly not those portions that have never been removed from their original 

 and much earlier strata, where they have merely undergone disintegration and decomposi- 

 tion. But where the iron is associated and interstratified with layers of clay, sand and 

 lignite, was the deposit made during the pliocene tertiary period ? We have already pre- 

 sented a summary of the evidence to sustain the affirmative of this question. But in his 

 recent able work, entitled The Iron Manufacturers' Guide, J. P. Lesley has controverted 

 this opinion. He takes the ground that the beds " are the weathered or degraded otu- 

 crops of the silurian limestone on which they lie," and are sometimes connected with 

 No. II, and sometimes with No. VI, of Rogers, which fact he thinks inconsistent with the 

 idea that they are tertiary. But we do not see the force of this objection. For if these 

 different formations, on whose edges or faces the hematite had been prepared by disinte- 

 gration, were under the ocean, why might not its waters wear off and re-deposit these 

 substances on different rocks during the same geological period, especially during their 

 vertical movements ? They might differ a good deal in age and still belong to the same 

 geological period, none of which seem to have been stinted for time. As will be seen, we 

 agree with Mr. Lesley that these deposits are " weathered and degraded outcrops " of 

 other formations. But the question is, when were the materials worn off and re-deposited ? 

 All our experience shows them to be below the regular drift, and to rest on rocks which 

 certainly are not newer than metamorphic Devonian strata. During which of the geo- 

 logical intervals in this wide gap were they deposited ? They are not consolidated (save 

 the iron to some extent) , but correspond exactly in this respect to the tertiary strata. So 

 they do as to the materials which constitute them. The white and variegated clays, as 

 well as the sand and gravel, could not be distinguished by the eye from those which we 

 see on the Isle of Wight and Martha's Vineyard. The white clay is not properly kaolin, 

 resulting immediately from the decomposition of feldspar, but has been deposited by 

 water, certainly in all those cases where it is interstratified with the other substances. If 

 these deposits are any of them older than the tertiary, say cretaceous, oolitic, triassic, or 

 permian, why are they not consolidated, as in all other places? Why do they retain so 

 exactly the lithe-logical aspect of tertiary rocks, if of some other age ? But it was the 

 lignite and fossil fruits of Brandon that specially arrested our attention, as having exactly 

 the aspect and degree of carbonization, which mark the tertiary coals of Germany and 



