from the Shales of the NortJiumherland Coal-field. 273 



all the processes can be determined more or less completely. 

 They were found at Newsham, but at different times. These 

 very interesting relics closely resemble the figure of the ver- 

 tebra oi Anth7'acosaurus given by Prof. Huxley in the 'Journal 

 of the Geological Society ' (1863, vol. xix. p. 63). Our speci- 

 mens, however, are larger, the neural arch differs a little in 

 form, and there is a very minute notochordal foramen. 



The body or centrum is biconcave, and appears to be con- 

 siderably flattened lengthwise. The margins of the articular 

 surfaces are reflected, so that in section the faces of the body 

 would present a sigmoid curve from the centre to the margin. 

 The height is a little more than the breadth, and the circum- 

 ference at the sides and below is well rounded, though there 

 is here and there a tendency to angularity ; but whether this 

 arises from original conformation or from accidental and un- 

 equal reflection of the margin, cannot be determined. The 

 upper margin of the anterior face is produced a little in the 

 centre, forming a rounded elevation immediately below the 

 neural arch, and is angulated at the flanks. The same region 

 in the posterior face presents a shallow concavity, exactly 

 similar to that represented in Prof. Huxley's figure referred to. 

 The sides of the body are somewhat concave, and transversely 

 wrinkled or coarsely striated. The minute notochordal fora- 

 men, which is only large enough to admit a stout knitting- 

 needle, is difficult to determine, though there can be no doubt 

 of its existence. 



The neural arch is comparatively small ; it is oval, the long 

 axis being perpendicular ; the lips of the arch are produced a 

 little in front ; behind they do not appear to. be so. The walls 

 of the arch are very stout, and pass upwards to form a long 

 high spinous process, which is nearly as high as the centrum, 

 and is thin, being much compressed laterally. 



The anterior zygapophyses are large ; their articular surfaces 

 are hollow and elongated transversely ; their inner borders are 

 confluent. The posterior pair are much distorted ; but they 

 appear to form wide, transverse articular surfaces, the faces of 

 which look downwards. 



The transverse processes are perfect in neither vertebra, 

 though in one of them the extremities only are lost ; they are 

 broad and much compressed from front to back, and originate 

 apparently in the sides of the neural arch and the upper sur- 

 face of the centrum. They project almost horizontally ; but 

 so much of their extremities is wanting that there is no dis- 

 tinct evidence that they are divisible into an upper and a 

 lower portion, corresponding to the head and tubercle of the 

 rib. The upper portion, however, is thicker than the lower. 



