34 ADDRESS TO THE BRITISH ASSOCIATION, 1881. 



land and the North of Europe were subjected to great 

 cold and buried under a vast sheet of ice. 



The ancient poets described certain gifted mortals 

 as privileged to descend into the interior of the earth, 

 and have exercised their imagination in recounting the 

 wonders there revealed. As in other cases, however, 

 the realities of science have proved more varied and sur- 

 prising than the dreams of fiction. Of the gigantic and 

 extraordinary animals thus revealed to us, by far the 

 greatest number have been described during the period 

 now under review. For instance, the gigantic Cetio- 

 saurus was described by Owen in 1338, the Dinornis of 

 New Zealand by the same distinguished naturalist in 

 1839, the Mylodon in the same year, and the Archaeop- 

 teryx in 1862. 



In America, a large number of remarkable forms 

 have been discovered, mainly by Marsh, Leidy, and Cope. 

 Marsh has made known to us the Titanosaurus, of the 

 American (Colorado) Jurassic beds, which is, perhaps, 

 the largest land animal yet known, being a hundred 

 feet in length, and at least thirty in height, though it 

 seems possible that even these vast dimensions were ex- 

 ceeded by those of the Atlantosaurus. Nor must I 

 omit the Hesperornis, described by Marsh in 1872, as a 

 carnivorous, swimming ostrich, provided with teeth, 

 which he regards as a character inherited from reptilian 

 ancestors ; the Ichthyornis, stranger still, with biconcave 

 vertebras, like those of fishes, and teeth set in sockets ; 

 while in the Eocene deposits of the Rocky Mountains 

 the same indefatigable palaeontologist, among other very 

 interesting remains, has discovered three new groups of 

 remarkable mammals, the Dinocerata, Tillodontia, and 



