S66 
POULTON : DOWKER BOTTOM CAVE. 
it. In this layer, at one spot, the remains of a dog' or wolf are 
common, and in excellent preservation. They are distinctly older 
than the historic layer. Thus the condition of this chamber seems 
to point to the impossibility of its having been inhabited during 
the deposition of the layers that we met with in our deep sections. 
At this time it seems to have held a deep still lake, at the bottom 
of which slowly accumulated the brown clay, gradually covering 
up the limestone blocks which continually fell from the roof. At 
length the condition changed, after 10ft. or more of clay had been 
formed. The supply of water to the lake increased, and caused 
its overflow, perhaps due to the increased rainfall, or to the 
opening by solution of additional fissures ; or possibly the lake 
broke through one of its boundaries. However caused, currents 
must have established themselves in the previously still water, 
and the supplies of sediment were hurried away to be deposited 
elsewhere. Stalagmite was deposited on the blocks last fallen 
from the roof, and lying on the top of the clay, and layers of soft 
and hard stalagmite succeed, probably due to varying rapidity in 
the rate of deposition, as suggested by Mr. Farrer in his paper. 
This physical history, shewn by the deposits cut through in 
the section, is especially interesting in the complete and distinct 
demarcation between a mechanical and chemical origin, so plainly 
shewn. The falls from the roof seem to cease at the surface of 
the clay, for no blocks (except just above the clay) were found in 
in the soft or hard stalagmite, although we have almost entirely 
removed it over a considerable portion of the floor. 
The following explanation may account for the sudden 
absence of falls from the roof. The same water, which — carrying 
an excess of bicarbonate of lime in solution — deposits it on the 
rocks and in layers on the floor, would also deposit cement 
between, and upon the limestone blocks of the roof, and hold 
them firmly together. Indeed it is very common in this and other 
caves, to find blocks of limestone held firmly by stalactite alone, 
sometimes in apparently most precarious positions, as when they 
