RIVER-DEPOSIT OF THE AMAZON, 
- At Section B, bed No. 2 becomes 
red and pink false-bedded sand ; at D, 
red false-bedded sand ; at F to H, red 
sand. At Section C, deposit No. 4 
becomes a pink and grey clay in thin 
beds, alternating with grey and yel- 
low sand; at D it loses its pinkish 
colour and becomes grey; at F is 
grey clay and sand; at G is false- 
bedded pink clay and sand, passing 
immediately into thick-bedded, green- 
ish-grey sand and clay, to the end of 
the cliff. This last set may possibly 
belong to an older deposit. The dark- 
coloured portions at C, E, and F, in 
the upper part of No. 4, are layers 
of bluish clay, containing leaves and 
pieces of carbonized wood at C, and 
with thin layers of oxide of iron at 
their base at Hand F. No. 3 is a bed 
of yellow sand containing thin layers 
of oxide of iron. 
Of this section 51 feet vertically 
are hidden when the river is at its 
highest stage. 
The layers of iron oxide above 
mentioned have been deposited by 
water charged with that substance, 
obtained from the red ochreous sur- 
face-loam, which has percolated 
through the sand beds, and has been 
precipitated in a thin sand layer be- 
tween the blue clay and the clay of 
No. 3 beneath. 
At Hytanahan, a place further up 
the river, and at many other places 
where similar yellow sand beds are 
seen, layers of this iron-rock occur. 
They are composed of fine-grained, 
ferruginous sandstone, more or less 
compact, arranged around a nucleus 
of almost pure oxide of iron, which 
in some places assumes the form of 
botryoidal masses, and in others of 
-eurved lamin, which frequently send 
layers down into the sand beneath as 
offshoots, at right angles to the pa- 
rent mass, forming quite a network of 
fantastically arranged planes. ‘They 
vary in width from 4 inch or less to 
‘MY SNINT ay? Wo “nanunpy yD Uor}IEgJ—'G “SIT 
HiT 
