196 L. V. Pirsson — Geology of Bermuda Island ; 



material previously reduced to a coarse saudy consistency by 

 some other agency. The evidence for this consists in the fact 

 that the particles of dense lava do not show the sharp angular 

 forms and splintery fracture surfaces which would be seen in 

 the latter case, but are distinctly dull of surface, rounded to 

 sub-angular, and with the pitted, dimpled texture caused by 

 repeated impacts, and characteristic of water- worn material. 

 It has, in other words, the aspect of a beach sand composed of 

 volcanic material laid down in the sea before surficial oxidiz- 

 ing agencies had had an opportunity to act, to any great 

 extent, upon it. 



Sample 22, from 645 to 665 feet, is quite similar, save that 

 the amygdaloidal character is nearly wanting, and the particles 

 are nearly all lava. In 23, from 665 to 695 feet, the material 

 consists of a few large fragments up to one and-a-half inches 

 long ; evidently in part angular chips from some larger piece : 

 these are brownish and partly oxidized on the surface of cracks. 

 Other pieces of a lead-gray color are not oxidized, and are 

 rounded to sub-angular and with pebbly surfaces. They 

 appear water-worn. 



Number 24, from 695 to 708 feet, consists of two things : 

 gray to brown water-worn, rounded pebbles and sand of more 

 or less altered lava and whitish amygdules, mingled with sharp 

 angular splintery chips, often showing somewhat conchoidal 

 fracture surfaces, of a dense hard, grayish-black lava. It is 

 evident that in this short stretch the drill passed through the 

 sands and gravels recorded above and encountered for the first 

 time solid lava in place. This is shown also by the fact that 

 at this point, as may be seen by reference to the diagram, fig. 

 1, it was found unnecessary to use any longer a casing for the 

 well, as the hole was now in solid rock. The bottom of the 

 fragmental deposited material may then be set at approxi- 

 mately 700 feet. 



From here to the bottom of the well the material is practically 

 of a uniform and monotonous nature, finely-comminuted rock, 

 such as would be obtained by pounding a dense compact lava in 

 a mortar. The tiny fragments are sharply angular with splin- 

 tery shapes and surfaces. The only variations that can be seen 

 among them is that some are darker in color, almost black, 

 others lead-gray, and the black samples are in the finer powder, 

 owing to the greater compactness and hardness of the rock. 

 They also contain in several instances, as shown on the diagram, 

 more or less amygdaloidal material, consisting of small calcite 

 balls the size of fine shot. This combination of greater com- 

 pactness of texture and the amygdaloidal condition is taken to 

 indicate the upper surface of lava flows successively penetrated. 



The one exception to this general uniformity of the samples, 



