62 A. E. Verrill—The Bermuda Islands; Geology. 
So when the percolating waters meet cracks or fissures, where they 
will be exposed to air, they deposit the calcite on and near their 
surfaces, giving rise to sheets and blocks of harder material, which 
may later stand out in relief when erosion takes place. (See fig. 8.) 
The reticulated cracks, made by the air-drying of mud, are thus 
filled in some places, as well as the larger fissures. When such 
waters trickle down the surfaces of the stumps and roots of trees, 
Figure 8.—Cliff of olian limestone, south shore, showing the irregular stratifi- 
cation and the deeply pitted surfaces coated and infiltrated with calcite, 
characteristic of most of the cliffs that are exposed alternately to the action 
of the sea-spray and dry air. 
the sands may be so hardened around them that complete molds of 
the roots, and even of the bases of the trunks, may be formed and 
preserved in the limestones. When the organic matters decay, casts 
may be formed in the molds. Some of the structures locally 
known as “fossil palmetto stumps” have possibly been formed in 
this way. These will be discussed later. (See chapter 24, pls. xix, 
Xx.) 
