IN THE MANCHESTER MUSEUM. 19 



Orthoceras acicularis, Brown, 1841. 



1841. Ortlwceras acicularis. Brown, Trans. Manch. Geol. Soc , i., p. 220, 



pi. vii., fig, 39. 

 1849. ,, ,, Id., Foss. Conch., p. 249, pi. xxix='=, fig, 29. 



Type. — Shell long, and tapering very gradually to an 

 acute apex. Marked by many equidistant transverse septa. 

 The specimen has been flattened by pressure, and lies in 

 a small slab of shale bearing a few Ostracodes. 



Todmorden, Yorks. 



Yoredale Shales. Coll. Gibso7i. 



Orthoceras Browni, Gibson, 1841. 



1841. Orthoceras Browni, Brown, Trans. Manch. Geol. Soc, i , p. 220, 



pi. vii., fig. 40 

 1849. ,, „ Id., Foss., Conch , p. 249, pi. xxix.=:=, fig 31. 



Type. — Shell arcuated ; bearing a series of longitudinal 

 angular ribs, crossed by fine oblique striae ; septa oblique, 

 becoming increasingly separated as they ascend. 



Todmorden, Yorks. 



Shales of Millstone Grit Series. Coll. Gibson. 



Orthoceras Gibsoni (Brown), 1841. 



1841. Belemnites Gibsoni, Brown, Trans. Manch. Geol. Soc, i , p. 220, 



pi. vii , fig. 41. 

 1849. „ „ Id., Foss Conch., p 249, pi. xxix.-, fig 28 



Type.— Shell tapering but slowly, ending bluntly ; 



section circular. 



Crimsworth Dean, Yorks. 



Yoredale Shales. Coll. Gibson. 



Orthoceras obtusa, Brown, 1841. 



1841. Ortlwceras obtusa, Brown, Trans. Manch. Geol. Soc , i., p. 219, 



pi, vii., fig. 36. 

 1849. ,, „ Id., Foss. Conch., p. 249, pi. xxix -, fig. 30. 



Type. — Very stout shell, ending in a rounded extremity ; 

 surface marked by fine parallel undulating striae, which 

 suddenly increase in strength, and become more widely 

 separated at about half the length. Length, 50 mm.; 

 breadth, 30 mm. 



High Green Wood, Yorks. 



Yoredale Shales. Coll. Gibson. 



