On the Palæozoic Basin of the State of New York. Part III. An Inquiry into the Sedimentary and other External Relations of the Palæozoic Fossils of the State of New York
The objects proposed in this inquiry are—to give more precision to facts as yet imperfectly ascertained, and to discover, if possible, new materials for the history of these early times, and new points of connexion between the palæozoic basins of the State of New York and of Wales—countries which are therefore the subject of frequent comparison in these pages. This communication is divided into four parts. The first part, after a few preliminary observations on the agencies by which the sediments or sea-bottoms were laid down, will treat of their mineral character. The second will be devoted to the distribution and immediate relations of animal life to the strata which the fossil remains occupy. The third will deal with the “recurrence” or vertical range of these fossil species,—their order of precedence, duration, increment, and decrement throughout the older palæozoic epochs. The fourth, and concluding, part will consist of general statements and inferences. By the expression “external relations” is meant such as do not directly lead us to the consideration of structural or physiological distinctions; the latter belong to a separate and very important field of investigation. § 1. Conditions and characters of Sediments .—It being a generally received fact that palæozoic fossils usually passed their lives in and about the sedimentary strata in which they are found, some very brief remarks on the origin and nature of the latter may be excused. The agents concerned in the formation of strata may be divided into two great classes :—1st. The constant and superficial, often