BELEMNITES OF THE LIAS. 



85 



apex. I have some nearly as large from Robin Hood's Bay, and many others of lesser 

 magnitude from Huntcliff. My smallest specimen from HuntcliflF is 1-5 inch long; and 

 between these extremes my collection contains many examples, some more compressed 

 than others. 



Proportions. The diameter at the alveolar apex from v \o d being taken at 100, the 

 cross diameter is about or above 90, the ventral radius 40 to 44, the dorsal 60 to 56, 

 the axis 400. Near the apex the ventral and dorsal radii become equal. 



Phragmocone. The alveolar cavity is empty in the only specimen I could afford for 

 longitudinal section. The angle is about 28°, but near the apex 32°, the whole figure a 

 little arched. 



Locality. Toward the upper part of the Lower Lias, in Robin Hood's Bay, north 

 side {Simpson, CuHen)-, in the same position under Huntcliff {Phillips). In the Marlstone 

 beds of Staithes and Robin Hood's Bay is found a Belemnite much resembling this, 

 though usually with more distinct dorso-lateral grooves, and less distinct special striae. 

 It must be ranked as of the same species, and does not, I believe, occur in any higher 

 strata of the Yorkshire coasts. 



Observations. Mr. Simpson, who first noticed this form of Belemnite, describes the 

 section as circular ; it is, however, rather elliptical. He has recognised the younger forms 

 at Robin Hood's Bay (Nos. 971, 972), as I have also done at Huntclifi". One of the spe- 

 cimens bearing the same name in the Whitby Museum (No. 976) is now regarded by Mr. 

 Simpson, who discovered it at Robin Hood's Bay, as a distinct species, with the name of 

 B. scabrosus. It will be described immediately. Two others in that Museum (No. 458) 

 show no apicial grooves. As already observed (page 57), this fossil is allied to B. lavis, 

 — and, we may add, to B. subtenuis of Simpson and B. tripartitus of Schlotheim, though 

 the apicial plaits and grooves are usually so faint or so short as to make this analogy less 

 obvious. From B. Icevis its attenuated apicial region may be regarded as distinctive. 

 Specimens occur at Lyme Regis, referred by me to B. niticlus (p. 67), and figured 

 as a short variety (PI. XIII, fig. 34 b), which are much like this fossil, but have not the 

 apicial striae, and always present more or less of the double lateral grooving. Other 

 specimens from Lyme, which are referred to B. apicicurvatus, also resemble B. elef/ans, 

 except in the apicial part of the guard. 



Belemnites scabrosus, n. s. {Simpson, MS.) PI. XX, fig. 51. 



Guard. Elongate, slightly compressed, fusiform, tapering to a lengthened apex ; 

 one short ventral groove, two short lateral grooves, which extend into lateral facets ; 



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