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HISTORICAL GEOLOGY. 



(1) Herbivorous Dinosaurs. — (a) Sauropods. An idea of the skull in this 

 group is afforded by the following figures of Dijylodocus longus Marsh, found 

 near Canon City. The length of skull in this species was about 21 inches; of 



1207. 



1208. 



¥ig. 120T, Diplodocus longus, skull, side view (x J); 1208, id. upper view (x J); a, aperture in maxUlary ; b, antorbi- 

 tal opening; c, nasal opening; c', cerebral hemispheres; d, orbit; e, lower temporal fossa; /, frontal 

 bone ; f, fontanelle ; m, maxillary bone ; m', medulla ; n, nasal bone ; oc, occipital condyle ; ol, olfactory 

 lobes ; op, optic lobe ; p, parietal bone ; p/, pre-frontal bone ; pm, pre-maxillary bone ; g, quadrate bone ; 

 gj, quadrato-jugal bone. Marsh. 



brain, about three inches ; of body, 50 feet. The position and relative size of 

 the brain is shown in Fig. 1208 at c'. The teeth were peculiar, being very 

 slender and long, and confined to the terminal part of the jaws. The 

 animal is supposed to have been a hippopotamus-like wader, and to have 



lived on vegetation in the waters. 



