Sayles — Dilemma of Paleoclimatologists. 403 



the former periods when epicontinental seas covered much 

 more of the present continents than today, we are living 

 during a period of high relief and land emergence and of 

 accelerated geological processes. AYlien the epicontinen- 

 tal seas covered so much of the continents much more heat 

 was stored in their waters and not permitted to radiate 

 back into space as rapidly as is the case today on the con- 

 tinents, and especially in the polar regions, where so great 

 a part of the insolation is reflected away by the ice and 

 snow surfaces. There was a warm water heating system 

 which carried warmth to every quarter of the globe. The 

 seas of those periods of warmth and low relief are not even 

 imitated to-day, except imperfectly perhaps in one case, 

 the Red Sea. Here the cold bottom waters of the Indian 

 Ocean kept out by the sill at the straits of Bab-El-Man- 

 deb, do not enter, and the result is a sea with warm waters 

 from top to bottom, that approximates the mean annual 

 temperature of the Red Sea region. It is possible that 

 the Red Sea today approaches the conditions of the deep 

 oceans during the warm periods. "With a depth of 1,200 

 fathoms the bottom waters have never been known to fall 

 below 532 degrees F., absolute degrees. This is about 

 40 degrees F. warmer than water at similar depths 

 in the adjacent Indian Ocean. Is this 40 degrees F. due 

 to the stored heat of the sun or to heat imparted by the 

 lithosphere under the Red Sea, or to a combination of 

 both? 



The close agreement of our air temperatures and the 

 temperatures of the regolith presents an interesting case. 

 At the equator the mean annual temperature can be found 

 one yard below the surface. Ground temperatures in 

 middle and high latitudes several yards from the surface 

 are usually one or two degrees F. higher than the mean 

 annual air temperature of the places. Lane ls believes 

 that the snow cover in the northern states causes the 

 ground temperature about 6 feet below the surface to be 1 

 or 2 degrees above the mean annual temperature of the 

 place. In fact, observations of underground tempera- 

 tures several hundred feet below the surface would show 

 that they are in large measure controlled by latitude. The 

 writer finds 10 that the temperature of the earth between 

 400 and 500 feet from the surface, is higher in the south- 

 ern states than in the northern states bv about 16.5 



