Geology of the Bermudas. 441 



This would account for the perfection of the Foraminifer, but not for 

 the coprolitic nature of the principal material. 



VIII. Some instructive Photographs. 



(1) The Carving Out of Pinnacles.— One of the photographs which 

 I took at 7 p.m. shows a pinnacle on the north shore near St. George's, 

 probably in the Walsingham formation (PI. XXI, Fig. 2). The 

 hardening of the rock near the sea, by whatever agency it is effected, 

 results in some remarkable structures. If the whole mass were to 

 become indurated there would be merely a dense rock of more or less 

 monotonous outline. But inasmuch as the shell-sand becomes more 

 compacted into hard rock in some parts than in others, in consequence 

 of percolation acting irregularly, there are often pockets of loose sand 

 contained in harder rock. When the loose sand is washed or blown 

 out, pinnacles are sometimes the result. 



This is clearly seen in the second photograph (PI. XXI, Fig. 3). The 

 soft sand is being carved and etched out by the very agency that 

 originally deposited it. The unconsolidated sand is seen as being cut 

 out gradually by seolian action, and a pinnacle is in process of 

 formation, like the finished pinnacle of the former photograph. The 

 shell-sand here contains numerous land shells of the species Pcecilo- 

 %onites Bermudensis, var. %onatus, Yerrill, which can be seen in relief on 

 the wind-cut surface. This natural arch is at Bailey Bay, also on the 

 north shore. It belongs to the Paget Series (PI. XXI, Fig. 3). 



(2) The Formation of '■Pot-holes'. — The view is at St. David's Head, 

 near the lifeboat station. In the upper part of the section is seen 

 the wind-blown nature of the shell-sand formation (Walsingham 

 Series). Lower down the action of the rain and spray has produced 

 a honeycombed or reticulated appearance in the rock surface, which is 

 pitted with small holes. On the face of the opposite rock is seen the 

 process of formation of a 'pot-hole', by the revolving action of three 

 stones which are swirled round and round by the impact of the waves 

 during strong winds (PI. XXII, Fig. 1). 



(3) ' Pseudo-palmetto Stumps' — ' Pot-holes ' are considered by some 

 to be the same as the 'pseudo-palmetto stumps'. The indurated 

 sides of ' pot-holes' are supposed to become hard cylinders, and when 

 weathered out to look like the stumps of trees. This may be so if 

 it can be proved that they do weather out in this fashion, but it is 

 quite as likely that they are drainage holes in the older Walsingham 

 rocks; the calcific material in solution, being deposited on the vertical 

 sides of these watercourses, would cause the formation of these tubular 

 pseudo-fossils from which the less dense external shell-sand has been 

 denuded. 



There are places where ' pot-holes ' occur so thickly that they could 

 not be the fossil remains of a grove of palmettos. 1 It is not their 

 habit to grow so thickly together, and they prefer a peaty boggy 

 soil, of which there is not the slightest indication in the structure of 



distances from Bermuda of the first five are 53, 26, 18, 43, and 66 miles 

 respectively. The distances are prohibitive of the second explanation, even if 

 the enormous depths did not forbid. 



1 Agassiz, A Visit to the Bermudas in 1894, p. 269, pi. xxix. 



