418 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1944 
made by bison were recently reported from west-central Nicaragua. 
The latter are of more than passing interest because of their associa- 
tion with imprints left by barefooted human beings (pl. 10, fig. 1) 
as well as with those of other animals and birds. They were un- 
covered by quarrying operations in a deeply buried volcanic stratum 
at El Cauce, in the outskirts of Managua (Richardson, 1941; Richard- 
son and Ruppert, 1942). Studies of the deposits have led to the con- 
clusion that the track-bearing layer was produced by a flow of semi- 
liquid mud from a vent on higher ground. While the surface was 
still sufficiently soft to receive perfect impressions the people and ani- 
mals passed over it. Shortly thereafter a thin fall of dry cinders 
covered the tracks, preserving and protecting them so that today they 
are as sharp and clear as when first made. Subsequently there was 
another mud flow and eruption of black cinders and then a rapid suc- 
cession of thick mud flows (pl. 10, fig. 2). In the course of time these 
layers turned to stone, a phenomenon comparable to that occurring 
at Herculaneum after its destruction by Vesuvius in A. D. 79. A 
stream forming a channel some 65 feet wide and 10 feet deep then 
cut its way through the strata thus formed. Eventually the bed of 
the stream filled with silt, gravel, and water-rolled stones. Later the 
area was covered by a heavy fall of pumice from the eruption of 
a distant volcano, and during the following quiescent interval new 
stream channels were cut and a thick soil zone developed. Again 
more ashes fell and another soil zone accumulated to be covered in 
turn by pumice from a further eruption. Finally the present topsoil 
developed to a depth of from 4 to 5 feet. The lowest portion of this 
layer is an aeolian deposit representing a period of slow growth 
(Williams, in Richardson, 1941). The sequence of events recorded in 
this series of strata required considerable time for its consummation, 
and although conclusions as to the age of the footprints await the 
completion of volcanological studies now under way, it appears certain 
that appreciable antiquity is indicated.’ 
Journals of the conquest period presumably contain no references to 
bison for this area, and everything indicates that they have long been 
extinct in Nicaragua. Since their tracks and those made by men 
are unquestionably contemporaneous, the occurrence would tend to 
signify that the human occupation should be regarded as dating from 
fairly early times. Lending strength to this assumption is the fact . 
that between the footprints and overlying archeological remains are 
approximately 10 feet of deposits. Included in the material from 
the lowest cultural level of the later manifestations are potsherds from 
The work of F. B. Richardson, of the Division of Historical Research of the Carnegie 
Institution of Washington, and that of Prof. Howel Williams, of the University of Cali- 
fornia, who was cooperating in the investigations, was interrupted by the war but will be 
resumed as soon as hostilities have ceased. 
