The rock is composed of a _clay slate_; and it is here again remarkable, that this stone is not to be seen in any other place within some miles. It has received its name from some red paintings, (probably left on it by the Indians,) which have the appearance of hieroglyphics. To conclude. It will be seen from the above observations, that this country presents a vast field of most interesting research, and claims the attention of every traveller who is interested at all in geological inquiries. If what has been said will at all contribute to the enlargement of the general stock of our knowledge on these subjects, the writer will be much gratified; and it is his sincere wish, that the accuracy of his remarks may be tried, and his mistakes corrected, by the researches of succeeding travellers. ART. XI. _Notice of Professor Mitchill's Edition of Cuvier's Essay on the Theory of the Earth._ The American scientific public are under obligations to Professor Mitchill for bringing this book within their reach. It is one of the most eloquent, impressive, and instructive works on this grand but obscure subject, with which the world has ever been favoured. The reader is no sooner drawn within the current of Cuvier's eloquence, than he is borne along almost without the power or wish to escape. It is believed there are few intelligent and enlightened persons, whether geologists or not, who would fail to be gratified by a book which secures the understanding by a strict course of reasoning from facts, and delights the taste by a style bold, terse, and lucid, but at the same time rich and flowing. The analysis of this work has been ably performed in Europe, and there is, therefore, the less necessity to attempt it here. While we take the liberty thus to recommend it, we do not hold ourselves strictly bound to the admission of _every one_ of Cuvier's doctrines; and might, perhaps, wish that in a few instances he had been somewhat more explicit, or somewhat more qualified. The additions by Professor Jameson, of Edinburgh, are valuable and interesting, and are retained in the present edition. Those by Professor Mitchill will be perused with pleasure and advantage. The learned author has assembled, in one view, a great mass of facts, partly resulting from his own journeys and observations, and partly deduced from other respectable sources. We have no doubt that most of these facts will be considered by the scientific world as very interesting, whatever views they may entertain of the conclusions built upon them. The author has occupied himself principally upon those portions of the United States, which, by the organized remains both of animals and vegetables, with which they more or less abound, exhibit the most decisive and interesting evidence of changes and catastrophes, whose history is to be sought in the memorials entombed in the strata themselves.