Notes on Seeiions of Stonehenge Rocks. 67 



Knowles Hill, near Newton Bushel, south-east of Woodleigh, and 

 Combe Wood near Christow. The above list of localities might be 

 considerably increased, but enough has been said to prove that 

 ophitic diabases of the Stonehenge type are widely distributed ia 

 the West of England.^ 



Felsites. 



Felsites with flow structure — "rhyolites^' of some authors — also 

 occur in the West of England, but they have not attracted so much 

 attention as the diabases, and are probably not so common. My 

 colleague, Mr. Ussher, has sent up some specimens from the 

 neighbourhood of Waster Wood, between Kingston and Modbury, 

 which are closely allied to, but not identical with, the Stonehenge 

 rocks. These rhyolitic felsites must not be confused with the 

 well-known " elvans " (microgranites), which occur so abundantly 

 as dykes in Devon and Cornwall. 



Calcareotis CJiloritic Schists. 



The specimens included under this head are merely schistose greeu 

 rocks containing chlorite, calcite, leucoxene and other minerals 

 common in decomposed basic igneous products. They are in no 

 sense true crystalline schists. Some (No. 58) show traces of 

 vesicular lapilli and are undoubtedly cleaved basic tuffs. Rocks of 

 this type also occur in Devon and Cornwall ; but owing to their 

 decomposed condition they have not been frequently cut for micro- 

 scopic examination, and I am not able to quote many localities. 

 Specimens sent up by Mr. Ussher from Fowelscombe House quarry 

 and from Whitcombe Road quarry, south of Kingsbridge Road 



' The slide of diabase No. 71 is fioiD the stump of the obelisk discovered iu 

 1881 by the late Mv. H. Cunniiigton. Its position is marked S. 57 ou the map, 

 Wilts Mag., vol. sxi. Mr. Teall describes its composition as follows: — ''A 

 typical ophitic diabase. The original minerals were a pale-coloured augite, 

 felspar (probably labradorite), and titaniferous iron ore. The secondary minerals 

 are epidote, chlorite, and leucoxene." 



Of a section. No. 35, which was obtained many years ago, by Mr. J. Britton, 

 from the stone of the inner circle (No. 27 ou map), Mr. Teall remarks that it is 

 so similar to the above that it might have been a part of the same mass. The 

 diabases of the inner circle and those in the inner horseshoe are thus shown to 

 be similar. 



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