770 C. B. BROWN ON THE ANCIENT 
Upon the Madeira river the first red cliffs below the mouth of the 
Jamary, which at the time (owing to the comparatively high state of 
the river) showed only 30 feet vertically, are composed of mottled 
red and grey clay, with red clay on top in their upper half, and false- 
bedded brownish sand in their lower. The sand beds dip to the north- 
east ; and a few yards further on the clay forms the whole thickness 
of the cliff, coming down to the water-level. About the middle of 
the cliff’s front there is only 1 foot of brown sand above water, then 
comes a fine greyish-brown clay, irregularly interbedded with a 
curious light-bluish clay, which in one part contains fragments of 
unaltered leaves, and is 5 feet in thickness. Upon it lies a bed of 
grey clay 4 feet thick, and above comes 20 feet of red clay and loam. 
A few yards north-east of this these beds turn up quickly, and the 
mottled red and grey clay, commencing at the water’s level, thickens 
out, rising at an angle of 3°. It rests upon a layer of red and grey 
finely laminated clay, which runs a considerable distance with a 
thickness of about 15 feet, and then passes horizontally into red and 
grey mottled clay (fig. 4). The accompanying diagram shows the 
arrangement of these beds. 
Fig. 4.—Rough Section of Abela Cliff below Jamary. 
1. Red clay. 2. Mottled and grey clay. 
3. Greyish-brown clay. 4. Mottled clay. 
5. Brown sand. 6. Red sand and grey clay. 
Near Baetas, on the west bank of the same river, is the following 
section :— 
ft. 
5 Fine red argillaceous sand. 
4 Grey clay. 
20 Grey, white, and yellow sand. 
4 Coarse sand. 
+ Hard iron-cemented clay. 
10 Fine bluish-grey clay. 
Upon the Purus river there are many fine cliff-sections; but as it 
would take up too much space to record them all, I will merely de- 
scribe two rather striking ones, viz. that at Maniwa, some 800 miles 
up, and one at Berury, near the mouth. In the diagram of the 
former (fig.5), at a number of vertical sections through different spots, 
marked A, B, C, D, &c., we find the beds arranged as follows :— 
At Section A we have :—1. Mottled red and yellow clay; 2. Red 
sand; 3. Yellow sand; 4. Pink, red, and grey clay, alternating with 
grey sand. . 
At Section B we sce that bed No. 1 has become red arenaceous 
clay ; at D a mottled clay ; and at G a red loam. 
