GENERAL MEETING. 93 
Mr. F. W. CuarkeE suggested that the difficulty in the way ofa 
_ chemical explanation of volcanic phenomena was due to our ignor- 
ance of chemical force under high pressures. Spring has lately 
shown that chemical union could be brought about by pressure 
alone. Hence, water coming in contact with molten rock matter 
in the interior of the earth might be prevented from dissociating. 
If, however, dissociation takes place, we may conceive that water 
may play the following ‘part in volcanic explosions. Gradually 
filtering through the surface rocks to the hot lava, it would undergo 
slow decomposition, and great quantities of mixed oxygen and hy- 
drogen would thus slowly accumulate. Now let a process of cool- 
ing begin. Soon the temperature at which oxygen and hydrogen 
unite would be reached, and explosive union would occur. This 
may account for volcanic explosions, at least in part. By sucha 
process, potential energy is gradually stored up, to be later, sud- 
denly or instantaneously, released. This hypothesis does not ac- 
count for volcanic heat, but presupposes its existence. 
Mr. Waite, referring to Mr. Powell’s remarks on the instability 
of continental areas, said that the prevalent doctrine of the perma- 
nence of oceans, and the gradual development of the continents, 
was not sustained by paleontology. Continents were needed some- 
where to develop the land plants and land mammals which ap- 
peared during the emergence of the known continents. 
Mr. Harkness pointed out that Mr. White was postulating un- 
known continents to support the Darwinian hypothesis, to which 
Mr. White assented. 
Mr. Powe. added, that in detailing the great cycle of geologic 
events, he should have included metamorphism as a sixth term, re- 
sulting from burial by sediment; and Mr. Durron remarked that 
he had included this consideration in a paragraph contained in his 
written manuscript, but not read. 
Mr. McG&e made a communication on 
THE DRAINAGE SYSTEM AND THE DISTRIBUTION OF THE LOESS OF 
EASTERN IOWA. 
[ Abstract. ] 
The most conspicuous geographic feature of eastern Iowa is 
the remarkable parallelism among its water-ways. Yet the region 
comprises two essentially distinct geologic tracts; and the coincidence 
