170 Reviews — Prof. Dr. Ferd. Roemer's Bone Caves of Poland. 



gretted, with respect to the specimens found in the Caves of Ojcow, 

 (pronounced Oizoff), that it cannot be always positively stated from 

 which bed in the caves they were taken, but the case is the same with 

 most of the caves which have been excavated in Germany." 



The Caves all occur in the White Oolitic Limestone, which con- 

 sists of a series of beds in all several hundred feet in thickness, 

 often forming precipitous cliffs. The entrances to the caves vary 

 from 10 to 30 feet above the level of the valley. Probably they 

 were at the same level, originally, as the bottom of the valley ; but 

 this has been cut down deeper by subaerial erosion leaving the caves 

 at their present elevation. In their physical aspect these caves 

 closely agree with those of the Oolite of Franconia. 



The solid rock is very seldom seen on the floor of the caves. As 

 a general rule, there is a deposit more or less thick of broken stones 

 and earth. The pieces of stone are angular fragments from an inch 

 in diameter to the size of the fist, and consist of White Jurassic 

 rock, similar to that forming the sides of the cavern. Amongst 

 them are a few larger blocks of limestone, varying from the size of 

 a man's head up to several cubic feet. The earth fills the intervals 

 between these angular stones; it very seldom forms a distinct bed 

 of itself. It is of a dark brown colour, and when carefully examined 

 seems to be a calcareous clay consisting of extremely fine particles ; 

 when moist, it is plastic and very adhesive. This mixture of lime- 

 stone fragments and brown earth forms a more or less considerable 

 deposit, sometimes as much as six or eight feet thick on the bottom 

 of all the caves. If we ask how this deposit was formed, it may be 

 replied almost undoubtedly that the pieces of limestone thus heaped, 

 up gradually crumbled from the top and sides of the cavern. The 

 limestone, although firm and compact when fresh, is permeated by 

 numerous fine cracks or fissures which when weathered are more 

 distinctly seen, and in course of time cause the rock to fall in angular 

 fragments. On isolated walls of rock this disintegration of the 

 stone may be distinctly seen, as small pieces become loose and fall 

 down. People who have remained some time in the caves have 

 occasionally heard small pieces fall from the roof. In no single case 

 had the stones forming the floor of the cave been subjected to the 

 action of water. This theory cannot be maintained for a moment, 

 as may be shown both from the angularity of form and from the 

 similarity of the rock. Hounded pebbles, such as are found in the 

 brooks flowing in the valleys beneath, are never found in the caves ; 

 there are no pieces of any other rock except the limestone forming 

 the sides of the cavern. 



There is a little more difficulty in deciding positively the origin 

 of the brown earth. The idea of its having been washed in from 

 the outside is probably not worth considering ; the more probable 

 explanation is that it is the argillaceous residuum of the limestone 

 which has been acted iTpon by the carbonic acid contained in the 

 water. Some small amount of clay is in fact a peculiarity of the 

 limestone. 



In most of the -cases there are horizontal layers of coarsely crystal- 



