96 PROCEEDINGS OF THE ACADEMY OF [1898. 



present inclined position will probably cause the fall of the upper 

 part first, thus obliterating another proof of what the structure was 

 in former times. Professor Oscar Carter said, when I showed him 

 the object in question and pointed out its significance: " A very 

 suggestive specimen, what else could it represent? It appears to be 

 a last remnant of the wall of a crater." Of course, it requires some 

 little imagination to see such a connection, but the principal empha- 

 sis is laid on the surroundings and upon the cumulative proofs of 

 the volcanic rocks themselves. 



From the Haystack a narrow winding path in a general north- 

 easterly direction leads to an immense platform of basalt known as 

 Table Rock. Of this no photograph was taken, in order to spare 

 the remaining plate for the picture of the entrance to the cave. In 

 Plate V the entrance of what the people call the cave, is plainly 

 noticeable among the huge and partly broken rocks. The large 

 block lying on the left shows the triangular contour of the cross cut 

 of a crater wall in a manner sufficiently characteristic. The col- 

 lapsing process and the gradual breaking up of the great masses of 

 rock are at least partially recognizable in the illustration. To ob- 

 tain a general idea of what that cave really is, however, one must 

 ascend the debris surrounding the great wall of massive blocks, 

 climb upward along a rustic step-walk, mount upon the top of the 

 wall and gaze down into the cavity. The deep kettle-shaped cavity 

 is formed by the rock masses which are more or less split in various 

 directions, but the greater number are vertically cleft. That this is 

 an ancient crater I have not the slightest doubt ; that the formation 

 has never been a cave in the geological sense of the word is clear 

 from the fact that volcanic rocks never form hollow domes. It is, 

 however, possible to creep into the cauldron from the side entrance, 

 and boys are occasionally seen sliding or climbing down into the 

 hollow space from above. 



Volcanic craters vary a great deal in diameter ; this one is small, 

 its inside measure amounts, I think, to not much more than forty 

 feet, and in its depth somewhat less. Since the wall rocks of this 

 crater are cracked vertically and in the inner parts moved toward 

 the centre, it is self-evident that the inner diameter must have been 

 greater in the past. Here, as in other parts of the hill, the trees are 

 doing their work steadily, breaking the larger blocks into smaller 

 ones ; the decay is continually going on, and although the entire 

 sleeping crater is still standing where it was built by the ancient 



