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358 upon the ground that all traces of stratification are obliterated before the appearance of the veined structure. It is, however, now well known that the primitive structure has been detected after the appearance of the veins on the surfaces of glaciers—the veins, indeed, have been observed in the walls of crevasses cutting the original structure. It is proved thereby that the original structure remains in existence down to a low point, and that, so far at least, it is not obliterated."

It has also been urged that "the blue veins of glaciers are not always, nor even generally, such as we should expect to result from stratification. The latter would furnish us with distinct planes extending parallel to each other for considerable distances through the glacier; but this, though sometimes the case, is by no means the general character of the structure." With this observation I agree. It amounts, however, only to saying, that it is impossible to