THE IMPERFECTION OF THE GEOLOGICAL RECORD 289 



Professor Pictet, in his excellent review of this work, in com- 

 menting on early transitional forms, and taking birds as an illus- 

 tration, carmot see how the successive modifications of the an- 

 terior limbs of a supposed prototype could possibly have been of 

 any advantage. But look at the penguins of the Southern Ocean; 

 have not these birds their front limbs in this precise intermediate 

 state of ''neither true arms nor true wings"? Yet these birds hold 

 their place victoriously in the battle for life; for they exist in 

 infinite numbers and of many kinds. I do not suppose that we 

 here see the real transitional grades through which the wings of 

 birds have passed; but what special difficulty is there in believ- 

 ing that it might profit the modified descendants of the penguin, 

 first to become enabled to flap along the surface of the sea like 

 the logger-headed duck, and ultimately to rise from its surface 

 and glide through the air? 



I will now give a few examples to illustrate the foregoing re- 

 marks, and to show how liable we are to error in supposing that 

 whole groups of species have suddenly been produced. Even in 

 so short an interval as that between the first and second editions 

 of Pictet's great work on Palaeontology, published in 1844-46 

 and in 1853-57, the conclusions on the first appearance and dis- 

 appearance of several groups of animals have been considerably 

 modified; and a third edition would require still further changes. 

 I may recall the well-known fact that in geological treatises, pub- 

 lished not many years ago, mammals were always spoken of as 

 having abruptly come in at the commencement of the tertiary 

 series. And now one of the richest known accumulations of fossil 

 mammals belongs to the middle of the secondary series; and true 

 mammals have been discovered in the new red sandstone at 

 nearly the commencement of this great series. Cuvier used to 

 urge that no monkey occurred in any tertiary stratum; but now 

 extinct species have been discovered in India, South America, 

 and in Europe, as far back as the miocene stage. Had it not been 

 for the rare accident of the preservation of footsteps in the new 

 red sandstone of the United States, who would have ventured to 

 suppose that no less than at least thirty different bird-like ani- 

 mals, some of gigantic size, existed during that period? Not a 

 fragment of bone has been discovered in these beds. Not long ago, 

 palaeontologists maintained that the whole class of birds came 

 suddenly into existence during the eocene period; but now we 

 know, on the authority of Professor Owen, that a bird certainly 

 lived during the deposition of the upper green sand; and still 

 more recently, that strange bird, the Archeopteryx, with a long 



