﻿BKITISH FOSSIL CEPHALOPODA. 



Plate VI. 



Fig. 



1. Orthoceeas Avelimi. — From the Lower Llandeilo, Shelve. In the Museum 



of Practical Geology. Possibly Salter's type. 



2. Ibid. — From the same locality and collection. Possibly part of the same 



specimen as fig. 1. 



3. Orthoceeas Etheridgti. — From the Wenlock rocks of Eaeberry Castle, Kirk- 



cudbright. In the Museum of the Geological Survey, Edinburgh. 



4. Ibid. — From the same locality and collection. A section showing the true 



form of the septal surface. 



5. 5a. Ibid. — From the same locality and collection. Showing the hollow at the 



apex, and the form of the pseudoseptal surface. 



6. 6a. Ibid. — From the same locality and collection. Showing the folds on that 



surface. 

 [These figures are from drawings kindly supplied by Mr. C. W. Peach.] 



7. Orthoceras Maclareni. — From, the Lower Ludlow, Ledbury. In the col- 



lection of Dr. Grindrod. 



8. Ibid. — From the same locality and collection, but not the same specimen. 



9. Ibid. — From the Upper Silurian, Pentland Hills. In the Museum of Prac- 



tical Geology. The typical form. 



10. Ibid. — From the same locality and collection. Showing the septal surface. 



11. Orthoceras dimidiatum. — From the Lower Ludlow, Leintwardine. In the 



Woodwardian Museum. With upward imbrications. External cast. 



12. Ibid. — From the Lower Ludlow, Kington. In the Museum of Owens 



College, Manchester. Showing downward imbrications. 



13. Orthoceras argus.— From the Wenlock Shale, Kingswood Fordon. In the 



Museum of Practical Geology. 



14. Ibid. — From the Middle Bala, Holbeck Gill. In the Museum of Practical 



Geology. 



15. Orthoceras expansum. — From the Bala Beds, Desertcreat. In the Museum 



of Practical Geology. 



