great beauty when inhabited by the living zoophites whose skeleton framework they compose. Every polygonal star in the mass is the house of a separate animal, that, when withdrawn into its cell, presents the appearance of a minute flower, somewhat like a daisy stuck flat to the surface, and that, when stretched out, resembles a small round tower, with a garland of leaves bound round it atop for a cornice. The _Astrea viridis_, a coral of the tropics, presents on a ground of velvety brown myriads of deep green florets, that ever and anon start up from the level in their tower-like shape, contract and expand their petals, and then, shrinking back into their cells, straightway became florets again. The Lower Lias presented in one of its opening scenes, in this part of the world, appearances of similar beauty widely spread. For miles together,--we know not how many,--the bottom of a clear shallow sea was paved with living Astreae: every irregular rock-like coral formed a separate colony of polypora, that, when in motion, presented the appearance of continuous masses of many-colored life, and when at rest, the places they occupied were more thickly studded with the living florets than the richest and most flowery piece of pasture the reader ever saw, with its violets or its daisies. And mile beyond mile this scene of beauty stretched on through the shallow depths of the Liasic sea. The calcareous framework of most of the recent Astreae are white; but in the species referred to,--the _Astrea viridis_,--it is of a dark-brown color. It is not unworthy of remark, in connection with these facts, that the Oolitic Astrea of Helmsdale occurs as a white, or, when darkest, as a cream-colored petrifaction; whereas the Liasic Astrea of Skye is invariably of a deep earthy hue. The one was probably a white, the other a dingy-colored coral.