1897.] NEW YORK ACADEMY OF SCIENCES. 101 



reefs or rather the " flats " or leveled islands at an eighth of a 

 mile from the shore. There can be no doubt that when the 

 shore line extended half a mile further out and no submerged 

 hills existed to break the waves, wind and waves together 

 were able to sweep even large shells to a ver}' considerable 

 height above the water line. The sand at Elbow bay is so fine 

 th'it recognizable fragments of any kind must be excessively rare. 



The dunes along the south shore seem, for tlie present at least, 

 to be almost stationary ; but the shifting shore deposits will 

 afford material for a dune elsewhere. A few years ago, the beacli 

 opposite the Trott estate in Hamilton parish increased several 

 hundred feet within three or four months, but the winds have 

 carried much of the sand inland and the waves have washed 

 more of it to the sea, so that the shore line has returned almost 

 to its former position. 



This new formation has spread over the old, filling up irregu- 

 larities in the surface, covering the soil ; in turn it is becoming 

 covered with a new soil, becoming consolidated and in time it 

 will be cut down by surface and subterranean erosion as were 

 the older rocks on which it rests. 



The " Sandstone." 



The upper rock of the islands, known locally as the " Sand- 

 stone," is usually very fine-grained, wholl}' gritless, of a j^el- 

 lowish white or somewhat creamy color and almost pure calcium 

 carbonate. It is softer than pine wood and the numerous thor- 

 ougli cuts along the roads were made, for the most part, with 

 grubbing hoes; yet it is the building stone of the islands. In 

 .quarr3'ing, a prism, three feet square and eight or ten feet long, 

 is blocked out with a long-handled chisel or a large crosscut 

 saw, such as is used in sawing logs, then pried off with wedges 

 and afterAvard sawed into pieces of the required size, the final 

 shaping being done with an ordinary handsaw. As the rock 

 can absorb almost its own weight of water, walls must be coated 

 with Portland cement and whitewashed. The roofs, made of 

 thin slabs, receive several coats of whitewash, which is soon 

 converted into cementing material by the rain, and the stone 

 gains a hard surface which sheds water. The great water 

 catches on the government properties are merely broad surfaces 

 of the sandstone coated with whitewash. 



The consolidation or induration of this rock in place varies 

 greatly. " Veins " of hard limestone, usuall}- slender and prob- 

 ably mere tubes filled with stalagmite, are met with occasionally 

 in quarries and prove annoying. At times, the sand is wholly 

 unconsolidated and the rock is as loose as dune sand; men were 



