XX 



200, 1. Head Dictyospougia prlsmatica. 



200, 5. Read Cyatliospongia reticulata. 

 200, 8. Read Dictyospongia ramosa. 

 200, 14. For are read is. 

 200, 16. Read Dictyospongia redfieldi. 



200, 18. Read Dictyospongia tiiberosa. 



201, 1. Read Dictyospongia ? 



201, 25. Read Trevorton. 



201, 36. Read Pflanz. 



201, 40. Insert Didyrnophleps coiitusa, Scudder. A cockroach from Ver- 



million Co., 111. Mem. Bost. N. H. S. A"ol. 3, p. 530, pi. 29, f, 6. 

 Coal measures, XIII. 



202, 1. Insert Dieconeura arcuata, Scudder. A cockroach from Mazon 



Cr., 111. Mem. Bost. N. H. S. Vol. 3, p. 336, pi. 30, f. 4. Coal 

 Measures, XIII. 

 202, 5. Diagrams of the dentition of this fish from Pal. Ohio. Vol. 2, pp. 7, 

 8, will be given in the Appendix. 



202, 14. Read Huron and Cleveland, or Ohio shale. 



203, 7. The Huron shale of Ohio is not the Genesee of New York, but rep- 



resents all from the Marcellus up to the Portage. (J. S. N.) 

 203, 9. Insert Dinichthys terrelli, New. Pal. Ohio. Vol. 2, p. 7, and plates. 

 A diagram of the dentition should be given. (J. 8. N.) See Ap- 

 pendix. 

 205, 14. Read cylindraceum. 



205, 20. Read stramineum. (That is, made of straws. ) 



206, 2. Insert Diplodas compressus ; D. gracilis ; D. latus, from Pal. 



Ohio. Vol. 2, p. 44, pi. 58. (J. S. N.) See Appendix. 

 206, 26. Read Utica slate III a. All these graptolites are found in Utica, 



never in Hudson river slate. (R. P. W.) 

 206, 33. Read radicle. 

 206, 38. Read Retiograptus. 



206, 40. Read Utica slate III a. 



207, 2. Note. — In Pennsylvania, Formation No. Ill includes Hudson 



River slate and Utica slate. While the distinction is evident in 

 Middle Pennsylvania, it is very obscure or entirely disappears in 

 the Lehigh-Dauphin-Cumberland-Great Valley" range. Rogers' 

 .graptolites were probably found at the bottom of No. Ill, i. e., in 

 the Utica slate. Those collected by the survey in recent years 

 were got in the bottom beds (Utica). There are in Europe sev- 

 eral fixed horizons of graptolites. (See for convenience of ref- 

 erence. Prof. Lapworth's last paper in the Geol. Mag. of London, 

 Feb. 1889, page 65.) There is an Upper Silurian horizon of Grap- 

 tolites, and the entire family of the Monograptidce is confined to 

 that horizon. The t7'^?;ca horizon is much lower and older; and 

 there are other horizons still lower and still older ; to one of which 

 the observation on page 207, lines 12 to 15 refers. Diplograptus is 

 a genus of Graptolites supposed to be exclusively confined to Or- 

 dovician {Lower Silurian, Siluro-Cambrian) strata. No Dip- 

 lograptus has been accepted as a Cambrian graptolite by all 

 palaeontologists, although some Cambrian forms have been given 

 this name by individual palseontologists ; for example, Diplo- 

 graptus simplex. The evolution theory is very dogmatic and 



