70 A. EF. Verrill— The Bermuda Islands; Geology. 
- crops by the roadside, nearer the Harrington House, nearly at the 
highest part of the ridge, perhaps fifty or sixty feet above the sea. 
Near the Walsingham house there are several deep sinks, filled with 
sea water, and used as fish ponds and turtle ponds, which are formed 
in these rocks. 
The famous Walsingham caves (pl. xxi, fig. 2) with large stalac- 
tites,* Joyce’s Cave, and several other similar caverns in this dis- 
trict are in this formation, for the hard limestone, near the entrances, 
contains the red soil and Nelsonian snails. ‘There are many other 
outcrops of the same limestone, associated with red-clay breccia, and 
often completely filled with masses of the large Nelsonian snails, on 
the land of Mr. W.S. O. Peniston. The interesting Peniston cave,t 
with only one small entrance, which is on the top of a higher ridge, 
east of the Harrington House, also appears to be in the same rock, 
though I found no fossil snails.just there. The cave dips downward 
with a steep slope to below sea level, for there is a pool of sea water 
in the bottom. The slope is said to be over 80 feet deep. 
There is an excellent exposure of the Walsingham formation at 
the old quarry on the west side of Castle Harbor, and near Paynters 
Vale. Here the hard, compact limestone, formerly quarried for 
government works, is several feet above the sea-level. 
The harder limestone is here overlaid as usual with a layer of red 
clay, which is more or less indurated in places, or united into brec- 
ciated masses mixed with stalagmitic material and several extinct 
land shells, especially the large Nelsonian snails (fig. 45-47; also pl. 
xxvl). With these land snails numbers of a large marine spiral 
shell (Livonu pica, fig. 60) are often found here. These shells were 
carried from the beaches up over the hills in those days, just as they 
are today, by the large land hermit-crabs, who use them for shelter. 
Part of the red clay is here contained in pockets or cavernous places 
in the limestone. The fossil land snails occur here in the limestone 
as well as in the red clay material. At this quarry much of the 
harder limestone shows distinct sand-drift structure, which is still 
more evident in the rocks below and above it. 
The Walsingham limestone, with red-clay breccias, outcrops at 
many other places on the southwest and south sides of Castle Harbor. 
* See these Trans., vol. xi, plates xe-xciii, and ‘‘ The Bermuda Islands,” p. 58, 
plates xce-xciii. 
+ See these Trans., vol. xi, pp. 488, 471, pl. xciii, and ‘‘ The Bermuda Islands,’’ 
pp. 26, 59, pl. xciii, figs. 1, 2. Also below, Chapter 16, B. 
