[195]

Horizontal section: length 3 & 4 feet x 2: drawn in proportion after nature

The double lines represent sides of fissures: & these are slightly prominent.

The currilinear dotted lines, are not nearly in sufficient numbers, they show the figure of the arrangement of the coarser & finer particles in the Sandstone

Fig. B.—

/over

[South America, p. 124: "No. 20. ─ Ground-plan showing the relation between veins and concretionary zones in a mass of tuff."]

[195v]

Showing that relation below veins concretionary action in between bed of [illeg] ; dark line passes & many marbled lines represent immensely zones of concretionary action

Must be reduced. ─ the double generally straight lines represent fissures or veins ─ The circles & curves represent concretionary zones of different textures & colours ─ ought they not to be done with dotted lines ─ slight irregularities in my drawing must be corrected.