CARBON- 14 AGE DETERMINATION — P. H. H. ROBERTS 341 



they also were making a highly artistic form of basketry decorated 

 with a false embroidery. It is possible, of course, that when perish- 

 able materials belonging in the complex of some of the other cultures 

 of this period are found an equally high kind of industry will be 

 revealed. 



What may well prove to be one of the most important archeological 

 sites thus far found in North America from the standpoint of the 

 sequence and dating of cultures, as well as geologic data, is Danger 

 Cave near Wendover, Utah. The cultural debris there reaches a 

 depth of about 14 feet. The midden rests on an old beach of glacial 

 Lake Stansbury. The beach consists of two feet of sand deposited on 

 cemented gravels. Charcoal, wood, and mountain-sheep dung were 

 found in the sand layer. Radiocarbon tests of the dung gave an age 

 of 11,453 ±600, while the wood ran 11,151 ±570. Thus far no results 

 have been announced for the cultural material and it must be con- 

 sidered as being an unknown number of years later than the beach, 

 although the initial occupation may not have been long delayed after 

 the receding water opened the cave to habitation. The date of the 

 latter, however, will be extremely useful in geologic studies of the 

 area. This is particularly so in view of the fact that bat guano mixed 

 M'ith the gravels of an old beach of Lake Lahontan in the Leonard 

 rock shelter near Lovelock, Nev., gave a carbon-14 date of 11,199 ±570. 



The close correlation between the beach levels in the two caves is 

 important in showing that climatic conditions then were such that 

 there was a pronounced shrinkage in the two lakes. A similar phe- 

 nomenon is noted for ancient Lake Texcoco in Mexico where radio- 

 carbon tests indicate that the late Pleistocene shrinkage apparently 

 started approximately 11,003 ±500 years before the present. 



In South America two caves in Tierra del Fuego near the eastern 

 end of the Strait of Magellan yielded material that has given dates 

 of 10,832 ±400 and 8,639 ±450 years. The older of the two dates was 

 obtained from sloth dung and there apparently were no cultural as- 

 sociations. The date is important, however, because it has a bearing 

 on the last ice advance in the area and also the survival of the giant 

 sloth. It is interesting to note that the date agrees very closely with 

 the 10,455 ±340 obtained from similar material from Gypsum Cave 

 in Nevada. The date for the other cave, called Palli Aike, which con- 

 tained archeological deposits, was obtained from charred sloth, horse, 

 and guanaco bones. It is not only important in indicating that man 

 was present there at a reasonably early time but is also significant be- 

 cause the material came from hearths on the surface of a layer of 

 volcanic ash, and as the occupation of the cave apparently followed 

 closely after the eruption which deposited the ash the date probably 

 is approximately that for the last major eruption in the adjacent 



