MANSFIELD: ROXBURY CONGLOMERATE. 113 
one set of alluvial beds over the other. Some sections show beds of 
well-rounded materials and of sand among less worn fan stuff. The 
latter being nearer its source is seldom thoroughly rounded (ibid., p- 
450-451). The alluvial plateau of Deosai, which Drew regards as a 
high level deposit of converging streams that spring from the moun- 
tains, has a slope of four degrees for eight or ten miles from the moun- 
tains and is composed of stones mostly half rounded, some well rounded 
and a few angular. The boulders commonly range from one or two 
feet in diameter down to the size of the fist; but some masses occur 
six, fifteen, and even thirty feet across. A line of springs indicates 
the stratification. The alluvium of the main valley consists mostly 
of clay, often dark or drab, but in some places sandy and elsewhere 
gravelly or pebbly (ibid., p. 461-464). 
——:— Persia. According to Blanford’s observations in southern 
Asia, the gravel accumulations attain their greatest dimensions in the 
drier tracts. The gravel slopes in Persia extend five to ten miles from 
the base of the hills at an angle of one to three degrees. The greater 
part of the slopes consist of sand and pebbles, the latter more or less 
angular and mixed with large blocks. Fragments two to three feet in 
diameter are not uncommon even one or two miles from the base of 
the hills (W. T. Blanford,, a, p. 496-498). Huntington, from more 
recent observations in Persia, thus describes the alluvial formations in 
that region. “The junction between the gravel and silt is very indefi- 
nite. They appear to merge in places while elsewhere gravel overlies 
silt. Outside the band of finer gravel the borders of the plain are 
formed of coarser gravel, which increases in size and in ahgle of slope 
of surface as the mountains are approached. On the very edge the 
gravel becomes a mere mass of rough angular fragments of all sizes up 
to more than one foot in diameter and it is hard to say where the coa- 
lescing fans of the basin deposits come to an end and the creep from 
the mountain slopes begins. From Bendun to Bering a smooth plain 
extends southeast with a uniform slope so gentle that in thirty miles 
it amounts to but little more than 800 feet. From the mountains to 
the lake the plain is composed of limestone and slate pebbles, coarse 
and angular near the mountains, well rounded and small near the lake. 
It is hard to understand how gravel, though fine, can be transported 
and spread in a sheet on so gentle a slope” (Huntington, p- 250-251). 
Oldham (b, p. 464-465) describes the great gravel fans, found 
everywhere along the foot of the hill ranges of the drier parts of western 
and central Asia, in the following terms: ‘They form a continuous 
fringe along the foot of the hills and often extend many miles over the 
