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Professor Owen some teeth similar in outline to those of his genus 

 Dendrodus, he discovered in them precisely the same dendridic 

 disposition of the vascular canals as that which led liim to establish 

 the genus from Scottish fossils. Nor does the value of this appli- 

 cation of the microscope stop here, for Professor Agassiz has in- 

 formed me, that availing himself of the weapons which Pi'ofessor 

 Owen had so skilfully wielded, he has commenced a series of re- 

 searches, not only into the teeth but also into the structure of all 

 the hard enamelled bones of the Russian fossil fishes, by which he 

 will be able to show the same distinction in the other bones of the 

 genera of this class, which Professor Owen has successfully esta- 

 blished in relation to the hard parts of the higher order of animals. 

 In such hands, thei'efore, the microscope has become an instrument 

 of great utility in identifying ft'agments apparently obscure ; and, as 

 it has been applied to the shells of Mollusca, and even to the lowest 

 links in animal life, as well as to fossil plants, the geologist has thus ac- 

 quired a new and powerful auxiliary. I am here, however, treading 

 on ground now fortunately occupied by the Microscopical Society, 

 the active promoters of which are well entitled to our gratitude. 



Ornithichnites. — To American geologists we are indebted for our 

 acquaintance with this new class of phgenomena. The existence of 

 the fossil bones of birds of ordinary size had, it is true, been ascer- 

 tained by Dr. Mantell in the Wealden strata, but great was our 

 astonishment, and I may add our incredulity, when Professor Hitch- 

 cock first announced, that in rocks of considerable antiquity (the 

 exact age of which is still uncertain), there existed innumerable im- 

 pressions in successive layers, which must have been formed by 

 birds, some of them of gigantic size, and to which he boldly assigned 

 the name of " Ornithichnites." Various opinions were entertained, 

 and much scepticism prevailed concerning these impressions ; but 

 it is due to Dr. Buckland to state, that he never doubted that the 

 views of Professor Hitchcock wei'e founded on true natural analo- 

 gies, and he accordingly published this opinion, with illustrative 

 plates, in his Bridgewater Treatise. The recent visit of Mr. Lyell 

 to North America, and a memoir he has read, as well as a com- 

 munication from Dr. James Deane of Ma^sachusets, have neces- 

 sarily brought this highly interesting subject again before us ; whilst 

 a very remarkable discovery in natural history has at all events almost 

 entirely dispelled scepticism regarding the true bird-like character of 

 even the largest of the footsteps, however difficult it may be to ima- 

 gine the presence of such highly organized creatures at a very early 

 period. The observations of Mr. Lyell completely support the views 

 of Professor Hitchcock as to the littoral nature of the footstep de- 

 posit in Connecticut, and that the prints in question v/ere left by 

 birds on the mud and sand of former estuaries, the bottoms of which 

 were gradually submerged, and by the increase of fresh matter were 

 permanently preserved. 



Mr. Lyell illustrates the ancient phaanomena by reference to im- 

 pressions which he saw forming at low water on the mud of the sea 

 shore of Georgia by racoons and opossums, and covered by blue 



