198 Rev. John Adams — On Sarsen Stones. 



changed, and the felspar transmits light. Examined in this way I 

 find no traces of glass in a fine-grained specimen from Roxborough, 

 while it is extremely rare in another from Herbertstown, and very 

 abundant in the Eathjordan trap. 



Although there are Tertiary basalts which cannot be distinguished 

 from^ others of Carboniferous age, it is by no means asserted that all 

 Tertiary and all Carboniferous basalts are alike ; for great differences 

 certainly exist between augitic lavas of different volcanic districts ; 

 the same is true of those of the older geological periods, and similar 

 differences occur between rocks of various periods. It becomes 

 evident, therefore, that a dissimilarity within the range of such 

 variations can give no support to the opinion that there is an 

 essential difi"erence between rocks of different ages. Having now 

 examined a considerable number of rocks from various localities, I 

 intend shortly to publish some of the results, and hope to fully 

 justify the view which I have for some time maintained as to the 

 complete identity in composition and structure of eruptive rocks of 

 widely separated geological periods. 



Ill- — On the Sarsen Stones of Beekshiee anb Wilis.^ 

 By the Eev. John Adams, M.A., etc. 



EYERY one who has traversed our Chalk Downs must have 

 noticed here and there shapeless masses of grey stones, half 

 buried in the turf. Sometimes they are found in groups, like the 

 shattered ruins of some ancient temple, and at other times they 

 occur in isolated blocks, as though giant hands had hurled them at 

 random over the hills in wanton sport. At one place, near the 

 village of Kennet, they assume the appearance of a multitudinous 

 flock of sheep, and are known by the appropriate designation of 

 " G-rey Wethers," whilst at other places in the same vicinity they 

 bristle on the hill-sides, and trail along the valleys like the debris of 

 an avalanche or the moraine of a glacier. Nowhere do they exist in 

 such profusion as on the west of Marlborough, but they are found 

 scattered over the whole Chalk area of this district. At the western 

 end of it they consist chiefly of saccharoid sandstone. Further east, 

 especially around Newbury, they become smaller, harder, and more 

 crystalline ; whilst in the neighbourhood of Great Bedwyn, and 

 occasionally elsewhere, they take the form of pudding-stone, being 

 agglomerations of flint pebbles, cemented together in a matrix of 

 siliceous sand. The name by which these stones are generally known 

 is " Sarsens " or " Sassens," and there are various opinions current 

 concerning the meaning of the word, many of which are so far- 

 fetched and improbable that they are undeserving of notice. Aubrey 

 traces the word to the village of Sarsden, three miles from Andover, 

 and thence to Csar's dene, Csesar's dene, Csesar's plain, now Salis- 

 bury Plain. "Nat. Hist, of Wiltshire," p. 44. Higgins derives it 

 from a Persian word, " Celtic Druids," p. 6 ; and Stukeley from the 

 Phoenician language. The commonly received derivation is from 



' From the "Transactions of the Newbury District Field Club," 1871. See 

 G-EOL. Mag., No. 105, p. 117. 



