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Show 244 EXPLANATIONS. a disregard of everything that pointed in the opposite di rection. The great unquestioned facts of a ~uccession of birds and mammals to the fishes and reptiles, these being also the next higher classes in the scale of the naturalist, tell nothing to this writer, as the succ.ession of the rep· tiles to the fishes told nothing before. From the slight remarks with which he passes over these facts, an unlearned reader would hardly suppose that they were of the least sigHificance, while, in reality, they are of the greatest. It is much the same as if a historian were to sink all such events as changes of dynasties, and fix attention up9n the displacement of under-secretaries of state. And what makes this conduct the more marked is, that the minor facts upon which he fastens for the purpose of iupportin~ his own theory are mostly presented to us In circumstances ·which show their uncertainty and the likelihood of their being superseded. For example, the earliest traces of birds do not indicate marine forms, which, according to n1y general views, ought, he says, to be the case. J.nstead of natatorial birds, they are waders and runners . Let the reader judge of the character of this objection when he learns the real circumstances of the case. The traces of birds here spoken of are merely a few font-prints found upon certain rock surfaces in America. Not a bone of these animals has been found in this early period. It must there1"ore be inferred, either that the circumstances were not favotable for the entombment of the bodies of these bird~, or that our researches in the strata formed at the time wht;n they lived have been insufficient to discover them. If such be the case with birds which lived upon shoresplaces where, as we learn from the nature of the strata, accumulations of sand and mud were constantly taking IJlace, it is of course not to be expected that any remains of natatorial.birds should be found, animals mostly living far out at sea. To put the case in its strongest form-:foot- prints on shores being the record of the birds of this era, we are not to expect any traces of such birds as, g:enerally speaking, are not in the way of m.aking foot~prmts on shores. I might go further than th1s, and p01fl:t out that certain natatorial genera have feet not t? be ,dJshngui~ hed froin those of waders, so that certain ot these foot-prints may be those of natatorial species after all; but I feel it to be my best duty in the case only to deny tha\ EARLY CET ACEOUS FOSSILS. 245 we are in circumstances to say that waders and runrJ ers were. the first created b~rds. 1\-fr. Lyell, who stands as high as this or any ~th~r w~·Iter on geology, says, with regard to those very ornithiChnites, as they are called-" This sand~ tone _is of J?Uch higher antiquity . than any formatimJ In whiCh fossil bones or any other Indications of birds have been detected in Europe. Still we have no ground for inferring from such facts that the feathered tribe rnade its first appearance in the western hemisphere at this period: It is too com'"!'on a fallacy to fix the era of the first creatwn of each tnbe of plants or ani1nals and even of animate beir.gs in general, at the precise ;oint where our pr~sentretrospect~ve knowled_ge happerr:s to stop.""' What now gives force to tlus observatwn is, the recent discovery of a new set of bird foot-prints-said to be of waders only-in the carboniferous formation of Pennsylvania: The emergence of such a fact in the midst of the reviewer's speculations on the foot-prints of the N~w Red Sand~ tone, forms a most emphatic comr_nentary on all decisive Inferences where the facts are obv1ously casual and isolated. Of a somewhat different character are the reviewer's remarks on the first relics of mammalia-the few bones of cetacea from the Lower Oolite and of marsupials from ~he Stonesfield Slat~. Here t~e yery first mammal family 1s ur~doub~edly manne; and, If ~t were to receive equal consideration wtth t.he grallatonal foot-prints he ouo-ht certainly to admit that it favors the developm~nt theo~·y. But he escapes from this clairn by a mode of his own. He has not seen these rel~cs ! Th~ American foot-prints we~e good eviden.ce, w~thout being seen; but a fact wh1c~ makes agatnst h!s theory requires personal inspectwn, even though It may cmne forward with the authority of Baron Cuvier.t He is tnore at ease with th~ marsupials, which are of course unequivocally land ammals. I have only here to refer to the fourth edition of my bo?k-pu.blished two . rnonths before the appearance of .tne. revie:V, and while I was unrecking of any great obJection betng grounded on this point-where it is "'Travels in North America, i., 255. t :·There is in the Oxford MusP.um an ulna from the Great Oohte ?f Enstone, near Woodstock, Oxton, which was examined by Cu·vte1· an.d p1·onounced to be cetaceous; and also a portion of a ,·ery large nh, apparently of a whale, from the samo locality."-· Puckland's Hridgew tte1· Treatise, i., ll5, note. |