40 SMITHSONIAN INSTITUTION 



the Hagerman locality it is often necessary to spend hours and even 

 days in just plain shoveling" of many cubic yards of sand to come to 

 the bone-bearing layer. Once reached the bones are for the most part 

 well mineralized, or petrified, and although more or less scattered are 

 usually complete. But often the separate bones are much broken or 

 cracked up, especially where they have lain for a long time near the 

 surface of the sloping hillside from which they outcrop. This neces- 

 sitates working very carefully around each bone, as developed, and 

 giving many of them special treatment to prevent their being pulled 

 apart in removing them from the loose sandy bed. 



The first care, therefore, was to make long strippings to remove the 

 overburden from the bone bearing layers. Then as the bones were 

 uncovered one by one or in groups and brushed clean on top and sides, 

 the cracks and soft places were saturated with a thin solution of gum 

 arabic (acasia). Following this treatment, as their condition and the 

 collector's experience suggested, they had to be still further protected 

 by pasting them with strips of burlap dipped in raw flour paste or 

 thin plaster of paris. This, when dry, forms a light, tough jacket 

 which securely holds each piece in its original position, and the speci- 

 men then may be turned over and the jacket completed on the lower 

 side to finish its preparation for packing and shipping. For skulls and 

 articulated sections this method had to be followed in nearly every 

 case. In certain sections in the deposit the bones instead of being sur- 

 rounded by a soft sandy mass, were completely incased with a nodular 

 or concretionary formation of varying thickness of very hard sand- 

 stone that is very tenacious and most difficult to break free from the 

 bone without injuring its surface. Sometimes the bones were thus so 

 deeply and solidly embedded as to make them almost worthless as 

 specimens. 



