{Pimelodus). Many small fishes, allied apparently to the 

 modern herring (Clupea), left their remains in great numbers 

 in the same deposits, and, with them has been recently found 

 a land-locked Kay (Heliobatis). 



The almost total absence of remains of fishes from the Mio- 

 cene lake-basins of the West is a remarkable fact, and perhaps 

 may best be explained by the theory that these inland waters, 

 like many of the smaller lakes in the same region to-day, were 

 so impregnated with mineral matters as to render the existence 

 of vertebrate life in them impossible. No one who has tasted 

 such waters, or has attempted to ford one of the modern alkaline 

 lakes which are often met with on the present surface of the 

 same deposits, will doubt the efficiency of this cause, or the 

 easy entombment of the higher vertebrates that ventured within 

 their borders. Tn the Pliocene lake-basins of the same region, 

 remains of fishes were not uncommon, and in some of them are 

 very numerous. These are all of modern types, and most of 

 them are Cyprinoids, related to the modern Carp. The Post- 

 pliocene fishes are essentially those of to-day. 



In this brief synopsis of the past ichthyic life of this Conti- 

 nent, I have mentioned only a few of the more important facts, 

 but sufficient, I trust, to give an outline of its history. Of this 

 history, it is evideut that we have as yet only a very imperfect 

 record. We have seen that the earliest remains of fishes 

 known in this country, are from the lower Devonian ; but these 

 old fishes show so great a, diversity of form and structure, as 

 to clearly indicate for the class a much earlier origin. In this 

 connection, we must bear in mind that the two lowest groups 

 of existing fishes are entirely without osseous skeletons, and 

 hence, however abundant, would leave no permanent record in 

 the deposits in which remains of fishes are usually preserved. 

 It is safe to infer, from the knowledge which we now possess 

 of the simpler forms of life, that even more of the early fishes 

 were cartilaginous, or so destitute of hard parts as to leave no 

 enduring traces of their existence. Without positive knowledge 

 of such forms, and considering the great diversity of those we 



