150 Stoneheuge: the Petrology of its Stones. 
caprice, can break off a fragment from one of these venerable monu- 
ments of a world-forgotten society of men, and appropriate it to 
himself, to serve no purpose whatsoever. I trust that any to whom 
Stonehenge is an object of veneration, or of interest, will acquit the 
author of this paper of having raised a hammer in such a spirit as 
this against these silent witnesses of an unrecorded past. The little 
flakes then separated from the Stonehenge blocks will be found to 
have served to add something, I trust, to the more intelligent kind 
of interest felt in Stonehenge: and these little fragments, with 
sections from some of them worked for the microscope, will be placed 
in the Museum of Salisbury for the use of any future petrologist 
needing to refer to them, so as to render unnecessary any repetition 
of even this mild iconoclasm. 
The total weight of some twenty fragments removed by me for 
microscopic investigation is under two ounces. 
Now the stones of Stonehenge are of four kinds. Of two of 
these I need say little. My colleague, Professor Preswitch, long 
since attacked the problem of the sarsen stones; and though the 
precise bed of tertiary sands which capped our chalk, and by con- 
cretionary segregation grew into the sarsen stones, may not be the 
Woolwich or Reading beds to which he’ attributed them, but are 
with greater probability to be assigned, as Mr. Whitaker has? 
assigned them, to the Bagshot sand; there can be no douht that 
these masses of concretionary sand stones are in fact the relics of 
beds of sand that once overlaid the chalk area of Wilts and in places 
became consolidated into the compact quartzite of the sarsen. Then, 
as the chalk became denuded and carved into its present valleys, 
these sandstone masses became broken up and dropped into the 
valleys where, in the form of the “Grey wethers,” they still 
lie, though the needs of man are rapidly causing them to dis- 
appear. 
It is of these sarsen stones that the great monoliths of Stonehenge 
'Quart. Journ. Geol. Soc. vol. x., pp. 123—130. 
? Report, Journal Geol. Soc., vol. xviii., pp. 271—274 (1862. 
) PP 
