2 INTRODUCTION. 



It wiU be seen that the Cephalopoda far exceed the other classes in number of 

 species, and amongst them the Ammonoidea are represented by a much larger num- 

 ber of species (12) than the Nautiloidea (3). 



The following is the list of the Cephalopoda here described :— 



The above list shows at once that the genus Macrocephalites preponderates in 

 number of species over all the other genera, a fact which is in itself suflBciently 

 significant. As however 15 species have been identified, we are able to determine 

 the horizon of the " massive limestone " with considerable certainty. The 15 species 

 which have been identified with specimens described from Kutch, occur there in 

 the following horizons : — 



The above list is a sufficient proof that the " massive limestone " of Baluchis- 

 tdn, for which I propose the name of " JPolt^phemua-limestone " from the frequent 

 occurrence of the enormous species of that name, is equivalent to the Charee-group 

 of Kutch, inasmuch as not a single species of the younger Katrol group is repre- 

 sented amongst the specimens from Baluchistdn. 



