520 



THE JURASSIC PERIOD 



(not pterosaurian) fashion, its posterior limbs modified for bird-like 

 walking, and most distinctive of all, it was clothed with feathers. 



The presence of 

 feathers, while yet 

 the body retained 

 so many reptilian 

 features, is remark- 

 able. But for their 

 preservation, it is 

 uncertain whether 

 the creature would 

 have been classed 

 as a bird or reptile. 

 The known speci- 

 men was somewhat 

 smaller than a crow. 

 The marvelous 

 'deployment of 

 aquatic and terres- 

 trial reptiles and of 

 birds makes the 

 scanty record of the 

 mammals all the 

 more singular. Only 

 a few jaw bones of 

 the size of those of 

 mice and rats have 

 been found. These 

 low types" are re- 

 The earliest f erred, without com- 

 plete certainty, to 

 marsupials. They 

 appear to have been 

 insectivorous. 



The insects of the 



Fig. 444. 



known bird, Archceoptcryx 

 macrura. The long verte- 

 brated tail, the clawed digits 

 of the fore limbs, and the 

 toothed jaws are ancestral 

 features to be specially not- 



ed. (H. von Meyer.) 



Jurassic appear to 



have included members of nearly all fossilizable groups not depend- 

 ent on flowering plants. 



Map work. For suggestions as to map work see Laboratory Exercises in 

 Structural and Historical Geology, Exercise X. 



