Bones discovered in a cave at Kirkdale, in Yorkshire . 179 
roof and sides are seen to be partially studded and cased 
over with a coating of stalactite, which is most abundant in 
those parts where the transverse fissures occur, but in small 
quantity where the rock is compact and devoid of fissures. 
Thus far it resembles the stalactite of ordinary caverns ; but 
on tracing it downwards to the surface of the mud, it was 
there found to turn off at right angles from the sides of the 
cave, and form above the mud a plate or crust, shooting 
across like ice on the surface of water, or cream on a pan of 
milk. (See Plate XVI. fig. 2). The thickness and quantity 
of this crust varied with that found on the roof and sides, 
being most abundant, and covering the mud entirely where 
there was much stalactite on the sides, and more scanty in 
those places where the roof presented but little : in many 
parts it was totally wanting both on the roof and surface of 
the mud and subjacent floor. Great portion of this crust had 
been destroyed in digging up the mud to extract the bones ; 
it still remained, however, projecting partially in some few 
places along the sides ; and in one or two, where it was very 
thick, it formed, when I visited the cave, a continuous bridge 
over the mud entirely across from one side to the other. 
In the outer portion of the cave, there was a mass of 
this kind which had been accumulated so high as to obstruct 
the passage, so that a man could not enter till it had been 
dug away. 
These horizontal incrustations have been formed by the 
water which, trickling down the sides, was forced to ooze off 
laterally as soon as it came into contact with the mud ; in 
other parts, where it fell in drops from the roof, stalagmitic 
accumulations have been raised on its surface, some of which 
are very large, but more commonly they are of the size and 
