NEW WORLD PALEO-INDIAN—ROBERTS 499 
put at a little over 10,000 (Sayles and Antevs, 1941). Gypsum Cave 
in Nevada is given as 8,500 (Harrington, 1933). Ventana Cave has 
not been dated as yet, but on the basis of similarities with other re- 
mains it is probable that the oldest level there would approximate the 
10,000 figure. Sandia Cave seems to fall into the same category as 
the Lindenmeier or Black Water Draw. 
No date has been suggested thus far for the human footprints and 
bison tracks in Nicaragua. The Confins man was considered as hav- 
ing lived a “few thousands of years ago” (Walter, Cathoud, and 
Mattos, 1937), and the remains in Patagonia have been estimated at 
3,000 to 5,400 (Bird, 1938b). An interesting question has developed 
in regard to the latter, however, since that estimate was made. If 
the subsidence of Laguna Blanca took place at the time of the retreat 
of the last ice sheet in that area, the cultural horizons antedating 
that occurrence would be much older. On the basis of a correlation 
between the varves in the Northern and Southern Hemispheres the 
time of the recession in the lake has been placed at about 10,000 years 
ago. Inasmuch as the deposits at Palli Aike Cave have suggested 
that the entire period of human occupation of the area may be twice 
as long as the interval since the retreat of the ice, plus a span of 
unknown duration when the debris was collecting on the original floor 
and the layer of volcanic ash was accumulating, something over 
20,000 years would be indicated.* In view of the situation in North 
America this appears to be too long a period, but it raises the question 
as to whether the remains may not be older than originally postu- 
lated. The problem is directly involved in that of the synchronization 
of ice ages in the north of the Northern Hemisphere with those in 
other parts of the world, and as there are various indications that 
simultaneous ice ages for the whole earth are not necessarily admis- 
sable it is possible the Patagonian phenomena were actually some- 
what later. There is no way of telling at this stage of the investiga- 
tions how long it took the migrants to travel from northern North 
America to the tip of South America. Some think of it as a slow 
and laborious process, others believe that it may have been relatively 
rapid. If 15,000 be taken as the maximum for North America and 
10,000 for the southern end of South America, the Nicaraguan mani- 
festations might be considered as approximating 12,000 to 13,000— 
providing, of course, they represent the earliest north-to-south drift— 
and Punin and Confins between 11,000 and 12,000. The North 
American data apparently have a better foundation than those from 
South America, and there is a possibility that the dates just postu- 
4Information received from Dr. Bird in a letter written after the appearance of the 
original article in Acta Americana. On the basis of present evidence Dr. Bird believes 
such an age far too great. 
