ORTMANN : TERTIARY INVERTEBRATES. 297 



centage like this. Taking together all species that might possibly be 

 Miocene, we would have : 



Miocene species .................... 22 



Mioc.-Rec. species ................. 13 



Mioc. & Plioc. species ............... i 



Eogene & Mioc. species ............. 8 



Directly opposed to Miocene age are : 



Older than Miocene. 

 Cretaceous species .................. 3 



Eocene species ..................... 5 



Oligocene species ................... 7 



Eogene species ..................... i 



"16=23^. 

 Younger than Miocene. 

 Pliocene species ................... 4 



Recent species ..................... 3 



Plioc. & Rec. species ................ 2 



~~9= 13 $ 



Thus 64 per cent, of the whole number may be taken safely as Miocene 

 specimens, while 23 per cent, point to an older age, and only 13 per cent. 

 to a younger age. This latter fact has apparently the following meaning : 

 there are, in these Miocene beds, more relations with the underlying than 

 with the overlying beds, and, accordingly, we are to consider this fact by 

 placing the Patagonian beds in the Lower Miocene. 1 



2. COMPARISON OF THE PATAGONIAN BEDS WITH TERTIARY DEPOSITS 



OF THE SOUTHERN HEMISPHERE. 



This result, that the Patagonian beds are Lower Miocene, has been 

 obtained by comparing them exclusively with deposits of the northern 

 hemisphere. Now it will be very interesting to compare them with other 

 beds of the southern hemisphere, and we shall see that there are extremely 

 significant connections. 



'According to Ball (18980) some of the North American and West Indian beds classed here 

 with the Miocene are really Oligocene ; this would, however, affect our conclusions only in so 

 far as it would increase slightly the relations with the older Tertiary, and would thus place the 

 Patagonian beds more decidedly in the lower Miocene. 



