256 RESEARCH IN CHINA. 
before being filled with the Huang-t’u. There are two considerations 
which render any conclusion indeterminate: (1) The valleys of the T’ang- 
hién stage had reached such advanced maturity that in soft rocks the 
ridges between them were reduced to monadnocks or groups of monadnocks, 
among which any valley now filled by Huang-t’u might seem to have been 
continuous on the rock surface. And (2) the Huang-t’u, now occupying 
such a valley, is not distinguished by any marks of age that enable us 
to say whether it is of the first deposit or of a later one. If it is not of 
the first or early Hin-chéu deposit, the Sing-ho may have extended its 
valley on an older surface of Huang-t’u; may have eroded that formation 
and worked on bed-rock; and may have aggraded its valley again—all 
in consequence of fluctuations of climate during the Quaternary. Until 
the history of the Huang-t’u is better known, we may not with confidence 
assign events connected with it to specific times. 
The considerations of the preceding paragraph do not, however, 
affect the inference that the streams, which during the T’ang-hién epoch 
had flowed southwesterly, were diverted to southeasterly courses before 
or during the Hin-chéu epoch; that is, before the beginning of the Fén-ho, 
epoch. 
FON-HO STAGE. 
The Fén-ho stage was characterized by profound mountain growth, 
involving both surface warping and normal faulting. We attribute to it 
the development of the Wu-t’ai-shan, the Ki-chéu-shan, the Ho-shan, 
the O-shan, the Féng-huang-shan, the Ta-hua-shan, and the Ts’in-ling- 
shan. ‘The altitudes of these ranges vary from 6,000 to 10,000 feet, 1,800 
to 3,000 meters. They are culminating crests of the mountain region 
of Chi-li, Shan-si, and Shen-si, and the elevation of these crests includes 
also the elevation of the lesser masses which extend beyond them. If 
our interpretation of the preceding Hin-chéu epoch be correct, altitudes, 
prior to the Fén-ho epoch, rarely exceeded 1,000 feet, 300 meters, and 
were generally but a few hundred feet. Thus, whether we consider the 
mountain growth with reference to the amount of altitude gained or area 
over which the movement extended, the effects are of the first magnitude. 
In seeking a name by which to designate the epoch of mountain 
growth characterized in the preceding paragraph, one’s thought turns at 
first to one of the great mountain ranges as presenting the most charac- 
teristic and obvious suggestion of the dominant activity of the time; but 
any stich range is marked by special features of structure or form, which 
are more or less peculiar to it, and the use of its name might, therefore, 
seem to give that special character to the mountain movements. The 
Fon-ho is a stream which antedated this epoch, which has been modified 
