396 GEOLOGICAL SURVEY OF THE TERRITORIES. 



pophyses support tlie ribs. The proximal cervicals are remarkable for 

 their compressed and elongate form. They are for a considerable dis- 

 tance longer than any dorsals. The lateral longitudinal ridge rises suc- 

 cessively nearer to the neural arch and disappears. The articular sur- 

 faces are vertically oval, flattened above and below. The inferior faces 

 are slightly grooved in line with the venous foramina. These vertebrae 

 diminish in length, and, after the posterior third of the series, materially 

 in depth. They diminish to terminal ones of very small size. In most 

 the decurved (?) pleurapophyses are broken near the base, but the basal 

 portion of various lengths generally adheres. They are as wide as a 

 rib and scarcely half as thick. On some of the most anterior vertebras 

 they are quite short and broad antero-posteriorly. They have much 

 greater anteroposterior extent on the terminal than the proximal cervi- 

 cal centra, having a base five-sixths the length of the latter. The zyga- 

 pophyses have relatively a larger size on these than any other vertebras. 

 In such the centrum is less compressed, though with concave sides, and 

 with a section rather quadrate. 



Measurements. — The cervical vertebras from the sixty-sixth to the 

 thirty -ninth are all longer than the dorsals; they commence four inches 

 in length, increase to five, and diminish to four again. 



Inches. Lin. 



Length of sixty-third cervical 4 9. 2 



Depth articular face of the centrum 3 8. 



Width articular face of the centrum 3 10. 2 



Total elevation ninth do 2 9. 



Anterior-posterior diam. third cervical 2 2. 



Transverse diam. third cervical 2 11. 



Length head of rib , 1 9. 7 



Width head of rib 1 3. 



Width shaft of rib 1 10. 5 



Many of the ribs preserved have been pressed upon the vertebras and 

 crushed. 



The first dorsal is that vertebra which first presents a distinct articu- 

 lation for a rib. The diapophyses are never much elevated above the 

 centrum and are longest on the thirteenth, (inserting seven supposed to 

 be lost.) Their form is stout and much depressed, and distally expanded. 

 They diminish gradually, and on the third are represented by a longi- 

 tudinal, slightly-concave, articular surface, somewhat similar to those of 

 the caudals. This surface is bounded above and below by a longi- 

 tudinal angulation; the superior is first distinct on the first, and bounds 

 the articular surface last on the third. They give the transverse section 

 of the posterior cervicals a pentagonal form ; that of the anterior dorsals 

 is nearly circular. The latter are strongly constricted medially, and the 

 articular faces are slightly concave. The external surface near the in- 

 cluded angle is coarsely ridged, in conformity with coarse cellular texture 

 of the spongy bone. The venous foramina gradually become more 

 widely separated, approaching each other again on the posterior cervi- 

 cals. On the dorsals they occupy the bottom of a more or less pro- 

 nounced concavity. These concavities, on the posterior dorsals, are 

 bounded externally by a strong obtuse longitudinal angulation, giving 

 a quadrate outline to the section of the centrum in this part of the series. 



The posterior cervicals are not readily distinguished from the anterior 

 dorsals. In the latter the ribs appear to be present, of reduced length, 

 judging from the smaller size of the remaining heads. The articular pits 

 continue to descend till their lower marginal ridge is the inferior lateral 



