















By William Gowland, FS.A., FIC. 47 
Note on the Nature and Origin of the Rock-fragments found 
in the Excabations made at Stonehenge by fr. Gotvland 
in 1901, %y Proressor J. W. Jupp, CB, LL.D. PRS, BGS. 
From the large collection of fragments which were submitted to 
me by Mr. Gowland, types of all the different rocks represented 
were selected, and thin sections having been made from them in 
the Geological Laboratory of the Royal College of Science, they 
_ were studied microscopically. 
Before proceeding to detail the results of these studies, it may 
be well to state what had previously been done in the way of de- 
termining the exact nature of the materials employed by the 
builders of Stonehenge. 
Sir R. C. Hoare, when writing his Ancient Wiltshire (1812—20), 
appears to have sent to Mr. James Sowerby a small specimen of 
each of the stones forming the monument of Stonehenge. Sowerby 
described these fragments as falling into the following classes: i. 
“Fine-grained species of siliceous sandstone.” ii. “ An aggregate 
of quartz, feldspar, chlorite,and hornblende” (twenty-six in number). 
iii. One “is a siliceous schist.” iv. Three others “are hornstone 
With small specks of feldspar and pyrites.” v. “The altar stone is 
nd the elvans or greenstone dykes near Dartmoor as possible 
sources from which the “greenstones” of Stonehenge may have 

* Gentleman's Magazine, ciii., pt. ii., 452-454. 
