M. Agassiz on Fishes. 339 



which -we now observe between fresh-water and marine fishes, it ap- 

 pears we perhaps go farther than facts warrant, when we admit in 

 the oolite series, and in those which are lower than it, distinct for- 

 mations of fresh and salt water. I rather think that the w T aters of 

 these remote periods, confined in less secure basins, did not then 

 present the same striking differences which we observe in our own 

 days. 



Such is a very meagre sketch of a history of the deepest interest, 

 and full of curious episodes, which are, however, somewhat difficult 

 to relate. The exposition of the details which it includes will be 

 the task of my life. 



The fifth number contains chiefly histories and descriptions 

 of genera and species met with in the formations of England and 

 Scotland.* The plates in this number are even more admirably 

 executed than those in the fourth livraison. The following 

 enumeration of the new British species may prove acceptable 

 to our geological readers : — 1. Palceoniscus. Of this genus the 

 following species are described : 1. P. Robiso?ii, found in the 

 limestone of Burdiehouse, near Edinburgh, and by Professor 

 Jameson in the Burntisland district. 2. P. striolatus, found at 

 Burdiehouse and in Fifeshire. 3. P. ornatissimus, in the lime- 

 stone of the Burntisland district. 4. P. elegcms, in the mag- 

 nesian limestone of Durham. 5. P.comatus, Durham. 6. P. gla- 

 phyrus, magnesian limestone. 7. P. macrophthalmus, magne- 

 sian limestone. 8. P. longissimus, magnesian limestone. 9- P* 

 cari?iatus, in the clay ironstone of Wardie. 



Lord Greenock found that many of the balls of clay-ironstone 

 at Wardie, to the westward of Newhaven, contained, as a nu- 

 cleus, coprolite, or portions of fish. He also found the follow- 

 ing species of the genus Amblypterus at Wardie, viz. A. amb- 

 nemopteruSi A. punctatus, A, striatas. Of the genus Osteole- 

 pis, the following species are mentioned as British : O. macrole* 

 pidotus, in the slate of Caithness and Pomona ; 2. O. microlepU 

 dotus, in Caithness and Pomona ; 3. O. arenatus, at Gamrie, 

 in Banffshire. Of the genus Acanthodes, the A. sidcaius is men- 

 tioned as having been found by Lord Greenock at Wardie. Of 

 the genus Cheiracanthus, the following species are enumerated 

 as British : 1. Ch. Marchesonii, found at Gamrie by T. Jame- 

 son Torrie, Esq. and others ; 2, Ch. minor, by Dr Traill in 

 Pomona. Of the genus Cheirlepis, the following British species 



* Although the fifth livraison is not yet published, we have, through the 

 kindness of the author, obtained a sight of it. 



