SIXTH REPORT OF THE DIRECTOR I9OO, 187 



movement has not been sufficient to effectively cut the cave 

 walls at their level. Material of this nature is also absent from 

 the second chamber. 



Late in the summer of 1909 a small excavation was made in 

 the deposits covering the floor of the mouth of this cave. On 

 digging down the size of the pebbles rapidly decreased, and 

 numerous small and well polished granitics and quartzes were 

 found among the limestone pebbles. At the depth of a few 

 decimeters a thin layer of very fine and clean gravel was en- 

 countered and immediately under this was a fine and well oxi- 

 dized clay containing a few pebbles so thoroughly decomposed 

 that the peen of the hammer easily cut them and left half of the 

 pebble imbedded in the undisturbed clay. The boundary be- 

 tween gravel and clay was very sharp and distinct. A block, 

 or a projecting edge from the cave floor, now interfered with 

 making a deeper cut in the small place chosen. The fine oxi- 

 dized clay and the few thoroughly oxidized pebbles speak very 

 decidedly for a deposit at least as old as that of the Hochelagan 

 sea. We should also state that the buried portion of the cave 

 wall was but a continuation of the exposed portion above. The 

 cutting of the whole cave opening was thus shown to be older 

 than the clay filling, and all subsequent erosion has hardly 

 modified the opening. That this cave in all its essential features 

 is at least as old as the glacial period must be considered as 

 demonstrated beyond the shadow of a doubt. 



Miscellaneous evidence. To the east of this cave is another 

 which can be reached by boat or by the sinkhole shown on 

 plate 2. The natural bridge between the sinkhole and the lake 

 consists of badly fractured material. About 500 pounds of this 

 rock were recently detached from its undersurface and allowed 

 to fall to the cave floor in order to insure the safe passage of 

 pupils doing field work in physiography. This cave is also cut 

 along a fault plane parallel with that of Darkroom cave. One 

 slickensided surface, by means of its well preserved diagonal 

 lines, shows that the small vertical displacement (throw) was 

 accompanied by a greater horizontal component. A view of the 

 mouth of this cave has already been seen in plate 1. It is one 

 of the few caves that have had their openings cut to the very 

 top of the cliff. A careful examination of plate 21 will show that 

 the same thing might easily have taken place there but for the 

 fact that the wedge-shaped mass pinched in between the nearly 

 parallel fissures has the smaller edge downward. In Bridge 



