DINOSAUR QUESTION t7 
In regard to the discussion as to whether Dinosaurs 
were contemporaneous in South America with the fauna 
of the Deseado, I can only say, we found no trace of a din- 
osaur or any other Cretaceous animal in the Deseado beds 
which we worked. As the Cretaceous beds lie as high as 
the Deseado and are also practically horizontally striated, 
dinosaur remains might be found on the same level. I 
think the assigning of any such material to these beds was 
due to failing to recognize the unconformity under the 
Deseado beds. As to the Notostylops fauna and dinosaurs 
being contemporaneous, | only worked the Notostylops 
beds at Mazaredo, but there I found nothing to indicate 
the contemporaneousness of these two groups. As I have 
shown above, Ameghino’s idea of the extent of the Noto- 
stylops or Casamayor beds was mostly at fault, and very 
much of that which he has designated as of Notostylops 
age is Upper Cretaceous. It is in these Upper Cretaceous 
beds that dinosaurs do occur and this seems to me to be the 
basis of the confusion. 
This Upper Cretaceous series is a field where consider- 
able work may profitably be done, in straightening out 
the relationships of the various layers to each other, their 
extent, and their relationship to the Salamanca and other 
Upper Cretaceous formations in other parts of Argentine. 
As to the age of the Deseado deposit which we worked. 
It is under the Patagonian, and therefore must be as old as 
the Oligocene. On the other hand it must be as young 
as the Eocene, lying as it does above the Upper Cretaceous. 
Of the three general faunas described it is clearly more ad- 
vanced than either the Casamayor, or the Astraponotus; 
so should be put as the youngest of these three. The 
Colpodon, the Astrapothericulus and the Notohippus, 
faunas are said to be interstratified with the Patagonian 
and therefore of the same age. The amount of advance- 
ment from the Casamayor to the Deseado is considerable 
and the relationships of the Deseado are fairly close with 
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