PLATE LXXIX. 



Zone of Lytoceras Jurense. 



Lytoceras Jurense, Zieten. Side view. This magnificent specimen, figured two 



thirds natural size, was presented to the Museum of 

 the Royal School of Mines by the Earl of Ennis- 

 killen, D.C.L., E.R.S. The Ammonite had been 

 sawn through to exhibit a vertical section of the 

 septse and chambers. There is no record of the 

 locality from whence the fossil came, but from the 

 penological character of the rock 1 believe it was 

 derived from the hard beds, Upper Lias, Dorsetshire. 



