Editorial Comiiieiit. 119 
verse to Mr. Manson's theory, that southern glaciation has 
never taken place. In the hght of the enormously long period 
of time embraced in the Quaternary, as lately brought out by 
studies in Iowa and Kansas, it may be inferred that tlie oldest 
glacial deposits are no longer recognizable, because of decay 
and re-deposition. Again, it is held by Mr. Manson that consid- 
erable areas escaped glaciation at sea level, especially in trop- 
ical latitudes where the sun's rays first pierced the envelope of 
clouds, and also in elevated regions east of extended Tertiary 
lava fields. 
3. The occurrence of salt and gypsum beds in the older 
rocks, has been taken as evidence of rapid evaporation under 
solar energy and this would hardly allow the existence of an 
earth-mantling cloudy envelope. But this inference is hardly 
justifiable. Such rapid evaporation, or slow and long-contin- 
ued desiccation, may have taken place under the action of 
earth heat as readily as under solar heat, and deposition would 
take place without extensive evaporation, from the cooling of 
saturated solutions of these salts or by the mingling of solu- 
tions which would cause their formation in excess of saturation. 
4. It is now well established that glacial deposits exist in 
the Permian and other formations, indicating that earth-heat 
had waned at that date so that glaciers existed. Hence the 
Pleistocene glaciers could not have been due to the secular 
cooling which dissipated the assumed cloudy envelope. 
!\rr. Manson, while admitting the evidence of Permian gla- 
ciation in East India and Africa, considers such glaciation as 
fragmentary, local and meager, and not shown to be extensive 
enough to prove the occurrence of a wide-spread ice age in 
Permian time. These phenomena are confined practically to 
the borders of the Indian ocean. If the}' have been correctly 
interpreted, they indicate a curious contrariety of climates, viz : 
ice action in tropical latitudes during eras in which tropical 
life flourished in circumpolar regions, and ice-action near warm 
temperate land and sea-life. Rather than accept these contrary 
conditions as evidence of general glaciation at sea-level, the 
author prefers to accept them as evidence that some 'iand 
masses were thrust up above the then existing snow line," such 
snow line being independent of latitude, but dependent wholly 
on altitude. If that inference be accepted, there must have 
