20. 
Climatic Optimum, Ina core, R10-10, length 4,15 m, (13.5 ft.), 
depth 4755 m, (2600 fms.), from 185 kilometers (114 miles) east of the 
Mid-Ocean canyon the post-Wisconsin layer was found to be unusually 
thick and contained foraminifera indicating a climate markedly warmer 
than the present, A radiocarbon ie") age determination was made on a 
section between 60 and 70 cm, by the geochemistry laboratory at the 
Lamont Geological Observatory, It was found to be about 5000 years old 
(See figure 6), This indicates an extraordinarily rapid rate of accumula- 
tion for the depth and distance from the continents, It is important to 
notice that this relatively thick sedimentary sequence shows no disturbance 
and contains evidence of normal deposition in the form of "worm" burrows 
and regular alternations of microfaunal changes, It is probable that this 
core was taken from the bottom of a closed basin in which turbid water 
collects, 
The sample for age determination was purposely taken between 60 
and 70 cm, because of the probability that the zone of warmer climate 
corresponded to the so-called Climatic Optimum of between 4000 and 
6000 B, P. Cores such as this when analyzed in detail may be expected 
to give a fairly complete record of the climatic changes which have taken 
place since the close of Wisconsin time, that is during the last 10,000 
years, 
Diatoms, | Top samples from about 400 cores have been studied 
by Mr. Horace G, Barber, Warwickshire, England, Mr, Barber came 
to the following conclusions in a letter to the laboratory: 
