Page:The Geologist, volume 5.djvu/16

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
2
THE GEOLOGIST.

admission that we do not know what they are, and we ask as frankly for information or suggestions.

Some indeed, such as the coffee-like berries, fig-like fruits, and nipadites of the London Clay, carry in themselves the palpable evidence of the classes to which they belong; but there are many specimens from other rocks remaining undescribed in many a collector's cabinet from the want of the ability to give anything like a reasonable suggestion as to what they were, and often, indeed, from the sheer incapacity to assign to them even any probable affinities.

And there they will lie and rot, possibly, if their owners are not bold enough to confess their ignorance and ask for information. For them our pages offer a means of inquiry which they do not possess for us. Anonymously they can ask their questions; openly we must ask ours. These chalk fruits puzzle us, we confess it. Not because we could not soon find some fruits like them in outward form and shape, but because we really do not understand their mode of preservation. Any one can see from our drawings (Plate I., and woodcut, fig. 1) that, flattened as they now are, such flattening is due to pressure in the substance of the rock, and that originally they were round in form. As they are preserved, they are roundish lumps of chalk enveloped in a dark brown ochreous skin.

A superficial observer might look upon this ochreous skin as the real rind of the fruit, but these fruit-masses are perforated by large teredines (see woodcut, fig. 1), as if the central part of the fruit had been of a solid nut-like character, such as we see in the vegetable ivory.

And yet, if this were so,—and teredines bore we know only in hard substances,—how is it that the central solid part has all rotted away, and its place been supplanted with the same soft calcareous chalk as the stratum in which the fossils were imbedded, while the more tender skin only is preserved?

In the same beds of chalk with the fruits, there are not uncommonly to be met with fragments of fossil wood, reduced likewise to thin skin-like ochreous layers, and bored too, through and through, by teredos. These not only show the rotting away of the solid fibrous wood, but also its reduction to the film-like state in which we see it spread on the surface of the chalk. But these wood-fragments might have lain on the still, slowly accumulating surface of the cretaceous ocean-bottom, and have rotted down to their last pellicle in the ponderous lapse of time. Not so the fruits: they, if solid,