PHYSICAL HISTORY AND GEOLOGY. 33 



distinguish the Bermudas from other islands having an ap- 

 parently related structure. I fully concur in the suggestion 

 thrown out by Prof. Rice that these accumulations could only 

 have been formed at a time when large areas of reef, and not 

 a simple atoll-ring, were exposed above water-level. At 

 the present day nearly all the sand is formed through the de- 

 struction of the existing land-mass, and not as a product of 

 disintegration derived from the growing reef. 



Prof. Rice, in his interesting observations on the geology of 

 Bermuda (loc. cit.,pp. 10-13), correctly distinguishes a " beach " 

 rock as underlying in many places the drift rock of the shores. 

 He instances as examples of such rock the fossiliferous stratum 

 which appears in the chain of islands stretching across Hamil- 

 ton Harbor, the conglomerate of Stock's Point, near St. 

 George's, which rises some twelve feet above the water, the 

 lower bed of Devonshire Bay, and much of the basal, nearly 

 horizontal, strata which appear on the south shore. As char- 

 acteristic of this beach rock, it is said that the beds nearly uni- 

 formly dip seaward, but at a very moderate angle, and that 

 they contain largely of the remains of marine animals (corals 

 and shells). The rock is in most cases very tough and hard, 

 and is largely the correspondent of the base-rock that has 

 already been described. 



We also found this beach-rock well developed at many 

 points along the south shore, where it rises some 5-8 feet, or 

 exceptionally more, above the sea-level. The series of nearly 

 horizontal ledges, sharply defined by their position from the 

 highly inclined layers of drift-rock by which they are sur- 

 mounted, or into which they graduate landward, which appear 

 basally at the Chequer Board and at Harris's Bay well illus- 

 trate the characteristics of the rock. I failed however, to de- 

 tect the uniform seaward slope of this rock which Prof. Rice 

 indicates, nor could I satisfy myself that the presence of 

 marine organic remains in a rock were conclusive for consider- 

 ing the rock to be of beach formation, unless, indeed, such re- 

 mains were abundant, or else showed by their positions that 



