251 



POSTPONED PAPERS. 



On the Paleozoic BAsnf of the State of New Yoek. 



Part III. An Inquiry into the Sedimentary and other External 

 Relations of the Palceozoic Fossils of the State of New York*. 

 Bj J. J. BiGSBY, M.D., Y.P.G.S., formerly British Secretary to the 

 Canadian Boundary Commission. 



[Read May 26, 1858.] 



CONTENTS. 



Introduction. 



§ 1. Conditions and characters of Sediments. 



§ 2. Palaeozoic Sediments ; their nature. 



§ 3. On the Distribution and immediate relations of Palaeozoic Animal Life 

 in Wales and the State of New York. 

 a. Calcareous Strata, b. Argillaceous Strata, c. Arenaceous Strata, d. Fos- 

 sils in Calcareous and Non-calcareous Strata, e. Divergence. /. Recur- 

 rence, y. Recurrence of Orders and Grenera. h. Recurrents of the De- 

 vonian System of New York. 



§ 4. On the grouping of Fossils, and their Order of Precedence. 



1. Potsdam Sandstone. 2. Calciferous Sandstone. 3. Chazy or Black- 

 river Limestone. 4. Birdseye Limestone. 5. Trenton Limestone. 6. Utica 

 Slate. 7. Hudson-river Rocks. 8. Medina Sandstone. 9. Clinton Rocks. 



§ 5. Increment and Decrement. 



§ 6. Duration of Invertebrate Life. 



§ 7. Epochal and G-eographical Diffusion of Species. 



§ 8. Recurrence. 



§ 9. Comparison of the Palaeozoic Basins of Wales and New York. 



Introduction. — 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 palaeozoic basins of the State 

 of New York and of Wales — countries which are therefore the sub- 

 ject 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 palaeozoic 

 epochs. The fourth, and concluding, part vnll consist of general 

 statements and inferences. 



^ For Parts I. and II. see Quart. Journ. G-eol. Soc. vol. xiv. p. 335 and p. 427. 

 VOL. XV. PAET I. T 



