Rosinus, Waloh, Lemery, and others writing after him followed not in the new path opened ont to them, but reiterated former absurdities.

Bruckmann thinks them a kind of pholas, or boring shell; Bourquet holds to the old notion of their being teeth of whales; Klein even in 1731 regards them as worm-tubes, although three years later he comes round to the opinion that they were nearly allied to the Argonautes; Spirulæ, and chambered shells. Dufay, one of the numerous writers who followed, states that burnt belemnites have the property of being luminous after having been calcined upwards of five years. We have not tried the experiment, and cannot, therefore, speak to the accuracy of the assertion.

Metamoephism, considered in its widest generality, comprises all the modifications which mineral substances undergo. It is naturally divisible into parts, according as its objects bear upon minerals or upon rocks. It is the metamorphism of minerals which I propose studying in this notice, and I shall describe it under the name of pseudomorphism. But as certain associations of minerals present all the appearances of pseudomorphism, with which they have been often confounded, it is necessary, in the first place, to consider these specially.

In this notice we commence the first of a series of articles descriptive of the geological diagrams, of which last month we commenced the issue. The notoriety which the discovery of flint implements of human manufacture of Amiens and Abbeville by M. Boucher de Perthes has attained, and the amount of research and investigation now going on renders it necessary for us to lay before our readers the chief points of the proofs of the human workmanship of those articles.