READING RIDDLES OF THE ROCKS 127 



creature as he was or may have been in Hfe, 

 is, to be honest, very largely guesswork, 

 though to make a guess that shall come any- 

 where near the mark not only demands a 

 thorough knowledge of anatomy — for the 

 basis of all restoration must be the skeleton — 

 but calls for more than a passing acquaintance 

 with the external appearance of living animals. 

 And while there is nothing in the bones to 

 tell how an animal is, or was, clad, they will at 

 least show to what group the creature be- 

 longed, and, that known, there are certain 

 probabilities in the case. A bird, for example, 

 would certainly be clad in feathers. Going a 

 little farther, we might be pretty sure that 

 the feathers of a water- fowl would be thick 

 and close ; those of strictly terrestrial birds, 

 such as the ostrich and other flightless forms, 

 lax and long. These as general propositions ; 

 of course, in special cases, one might easily 

 come to grief, as in dealing with birds like 

 penguins, which are particularly adapted for 

 an aquatic life, and have the feathers highly 

 modified. These birds depend upon their fat, 

 and not on their feathers, for warmth, and so 



