Palceozoic Geology. 559 



izing the different stages of the deposit should be given by Pro- 

 fessor Agassiz. The mimerous avocations in glacial and other geo- 

 logical inquiries, as well as, I regret to say, his partial ill health, 

 might alone have led us to account for the postponement of this 

 labour by M. Agassiz ; but in a recent letter to myself he has also 

 given the following important reason : — " When I promised you to 

 occupy myself with the determination of the fossil fishes of Dr. 

 Malcolmson, I believed that it would be as easy a task to me as the 

 determination of other ichthyolites, and I had no doubt that your 

 Devonian system must reveal quite a new world in the class of fishes 

 so very different from existing species. The effort has thrown upon 

 me the obligation of prodigious labour, to arrive at some precise re- 

 sults as to these curious objects ; and without giving you something 

 very imperfect, which I look upon as yet to be unworthy of pub- 

 lication, I must have recourse to your indulgence for the delay." 



Regretting sincerely that injustice seems to be done to Dr. 

 Malcolmson by this delay, I have, I confess, a pleasure in know- 

 ing that Professor Agassiz will well investigate all these curious 

 animals before he pronounces his final opinion. I can even assure 

 him, that strangely formed as these Scottish types may be, he has 

 yet to hear of some still more marvellous fishes which the Devonian 

 or Old Red system contains in assuming its Russian dress. In that 

 empire, where in some mountain tracts the system is black, slaty, and 

 crystalline, there are also vast undulations and plains in which it is 

 composed of slightly coherent, red, green, and yellow sands, shales, 

 and limestones. In some of these beds, near Dorpat, Professor Asmus 

 has detected gigantic fishes, which he is now describing ; and Mr. 

 Pander, so distinguished by his palseontological works on the en- 

 virons of St. Petersburgh, is preparing an account of others, some of 

 which are specifically identical with those of Scotland. I cannot 

 venture to anticipate what these naturalists will shortly lay before 

 the public, but I may be excused from announcing, that the mo- 

 ment I exhibited to Professor Asmus some drawings of the Scottish 

 old red sandstone fishes, his eye at once fell upon the Pterichthvs 

 as probably the type in miniature of an enormous creature, five 

 times the dimensions of our largest specimens, which is found in 

 rocks on which the University of Dorpat is situated. Anxious 

 that we should no longer be without some representatives of these 

 Palseo-ichtliyolites, whose bones are so gigantic that they were 

 formerly supposed to belong to mighty Saurians, I requested Dr. 

 Asmus to prepare casts of them, which he has obligingly executed, 

 and of these I now present a set to the Society, as one of the fruits 

 of distant comparison resulting from my Russian travels, and as a 

 memento of tlie instructive rf^searclies of Professor Asnuis. With 

 the mere announcement, liowever, of these mighty fishes I must now 

 take leave of the animals of primajval days, by saying that the car- 

 boniferous fossils of Russia are most singularly in acconhmce with 

 those typ(;8 whicli have l)(!en so ably elaborated by Mr. Phillips, Mr. 

 Sowerby, and other geologists in our own country, a point to which 

 I hope to call your attention at the next Anniversary. 



