GG 
THE GEOLOGIST. 
amongst other things I remember a portion of a tin kettle and a fragment 
of a basket, of the coarse kind used on board colliers and other ships. 
Here, then, is a cavern which the sea is at present fiUing, and in which 
it is depositing reUcs of man and portions of terrestrial mammals, but not, 
so far as I could discover, any marine organism, excepting the seaweed. 
Probably a careful search might have detected some small shells and other 
sea-ofFerings amongst the weeds, but I certainly saw nothing of the kind, 
nor were there any of the larger mollusks so constantly cast up on our 
beaches. There appears no reason, a priori, why some caves belonging 
to earlier periods may not have received their contents in a similar 
manner. 
Again, those who have visited the Cheddar Cliffs, in Somersetshire, 
probably remember that a considerable body of water issues from the foot 
of the right-hand cliff, not far above the village of Cheddar. This stream 
commences its subterranean journey about two miles off, where it enters a 
"swallet." 
It is scarcely possible to believe that it fails to introduce specimens of the 
natural history of the district into this cavern, or that it does not deposit 
organic relics, together with mud and stones, in at least some of the shel- 
tered nooks and recesses which probably occur along its course of fully two 
miles. 
I have no doubt that, at least, one of the celebrated caves of this county 
was in this way furnished with the materials which have rendered it 
famous. 
I am far from believing that the history of any cavern can be regarded 
as generally typical. Neither of the agencies above described could have 
produced the phenomena observed at Orestone, near Plymouth, where, in 
all probability, the fossils and the materials in which they were inhumed 
found a passage through an open fissure into the cavernous interior of the 
limestone. 
It would not be safe to generabze from any individual case, whether it 
be Kent's Hole, Windmill Hill Cave at Brixham, the caverns at Orestone, 
or a dirty dog on a study hearth-rug. 
I am, yours, etc., TVii. Pengelly. 
Lamorna, Torquai/, December 14:th, 1861. 
ISfortliampton Sands. 
Deae SiE, — In replying to Dr. Wright's communication in the last 
number of your excellent periodical, I offer him my apologies. The origin 
of my mistake was, in carelessly reading that part of Mr. Aveline's ' Me- 
moir on the Geological Survey of a part of Northamptonshire,' where 
he speaks of the confusion that formerly existed with regard to these sands. 
These beds have been assigned to the Upper Lias, although not by Dr. 
Wright, and are so coloured on more than one geological map. Por in- 
stance, in Reynolds's ' Geological Atlas,' lately published under the revision 
of Professor Morris, all the country over which the Northampton sands are 
so well displayed has been coloured, with the Lias, brown, a mistake which 
should be avoided if a second edition of that neat and otherwise useful little 
work is contemplated. 
The fact is, no one knows exactly where to place or with what to class 
these sands. Lias they assuredly are not. Mr. Avehne considers them 
to be equivalent to the Stonesfield Slate of Oxfordshire. This seems likely, 
