8 THE DESEADO FORMATION OF PATAGONIA 
Turritellas, Brachiopoda, sharks’ teeth, etc. Itis separated 
from the Deseado by a marked unconformity, one of 
the finest examples of unconformity I have ever seen. 
Evidently the upper surface of the Deseado was fairly new 
at the time of the transgression, or it is much disturbed by 
the transgression, the upper layers in places being broken up 
into sort of blocks and the crevices filled with Patagonian 
sands with the contained shells; just as I saw the beds 
on the seashore being disturbed by the waves of today. 
Then too in the basal foot of the Patagonian I found 
material which without question came from the underly- 
inp Deseado beds, various fragments of mammal bones 
bored by seashells, and with the Patagonian barnacles 
on them, but these were never more than a few inches up 
in the Patagonian. ‘The contact was not horizontal, but 
in the middle of the hill dipped down so that it came there 
onto the yellow beds of clays, and it was at this point only 
where we found bones had been washed out by the Pata- 
gonian sea. 
In the section the Deseado consists of layers 2 to 5, 
the white sandy clay below belonging to the St. George 
series and being Cretaceous. The contact below was 
also an unconformity, clearly marked for the white sandy 
clays were all horizontally bedded, while the Deseado is 
crossbedded in every direction, and has a distinct color. 
These white sandy clays of the St. George series are simi- 
lar to the same beds as shown in sections A and B (figures 
3 and 4), and extend in all directions for miles. Going 
down toward the Chico River one passes into the green 
shales that make up the upper part of the Salamanca and 
had similar invertebrate fossils. About ten miles to the 
north was another bed of fossil trees similar to the one to 
be described on the Puerto Visser side of the pampa. 
The character of the material making up the Deseado 
deposit, its variations in size and material, the presence 
of worn pebbles and bits of bone, show these layers to be a 
