Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/340

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Mr. Conybeare on the Origin of a remarkable
  1. That the globules themselves were casts moulded (in the manner already described) in cavities existing in the substance of the shell in question.

The most important of the appearances from whence these conclusions seemed to be deducible were the following.

Transactions of the Geological Society, 1st series, vol. 2 plate page 0613 fig. 2.png

The flat surface occupied by the globular bodies at one extremity of fig. 2. is terminated by the perpendicular face or escarpment (if I may so employ that term) formed by a portion of the flint elevated a little above the rest; and this escarpment will be found marked with minute vertical striæ, seeming to indicate that it had been moulded against the edge of a fragment of the striated shell already alluded to; similar striæ are observable round the edges of another elevated portion towards the centre of the specimen, in some degree resembling the mill-marks round the edge of a coin, and they again occur on both sides of a small vein, or rather dyke of flint traversing a cluster of globules, and cutting many of them through the middle. This striated dyke had therefore all the characters of an impression formed in a long and narrow fissure of the shell in question, and was connected with the globular bodies in such a manner that the formation of the latter could scarcely be assigned to any other cause than that which produced the former.

In order to represent these appearances more clearly to the eye, several slight liberties have been taken in the drawing fig. 1. the relative position of some parts of the original specimen has been changed, and to the indications in question, a more prominent character than they really possess has been given. The small scale of the general outline fig. 1. not exceeding one of the original size, has rendered this more necessary; but in fig. 2. a detached representation of the siliceous dyke traversing the globular bodies has been added, on a scale rather larger than the original.