February 9, 1905] 



NA TURE 



347 



Now the date arrived at by Mr. Penrose and myself 

 on astronomical grounds was about 1700 B.C. It is 

 not a little remarkable that independent astronomical 

 and archa2ological inquiries conducted in the same 

 year should have come so nearly to the same conclu- 

 sion. If a general agreement be arrived at regarding 

 it, we have a firm basis for the study of other similar 

 ancient monuments in this country. 



I have previously in these " Notes " referred to the 

 fact that the trilithons of the naos and of the outer 

 circle are all built up of so-called " sarsen " stones. 

 To describe their geological character, I cannot do 

 better than quote, from Mr. Cunnington's " Geology 

 of Stonehenge," ' their origin according to Prest- 

 wich : — 



" Among the Lower Tertiaries (the Eocene of Sir 

 Charles Lyell), are certain sands and mottled clays, 

 named by Mr. Prcstwich the Woolwich and Reading 

 beds, from their being largely developed at these 

 places, and from these he proves the sarsens to have 

 been derived ; although they are seldom found in situ, 



A B C D E F 



Fig. 6.— Face of i 



S££T 



ck against \s hi( 



owing to the destruction of the stratum to which they 

 belonged. 



" The abundance of these remains, especially in some 

 of the valleys of North Wilts, is very remarkable. Few 

 persons who have not seen them can form an adequate 

 idea of the extraordinary scene presented to the eye of 

 tfie spectator, who, standing on the brow of one of the 

 hills near Clatford, sees stretching for miles before 

 him, countless numbers of these enormous stones, 

 occupying the middle of the valley, and winding like 

 a mighty stream towards the south." 



These stones, then, may be regarded as closely 

 associated with the local geology. 



The exact nature of the stones, called " blue 

 stones," can best be gathered from a valuable " Note " 

 by Prof. Judd which accompanies Prof. Gowland's 

 paper. These blue stones are entirely unconnected 

 with the local geology ; they must, therefore, repre- 

 sent boulders of the Glacial drift, or they must have 



1 II lY/s Arcluteological ami Natural History Magazine, xxi. pp. 

 141-149. 



NO. 1841, VOL. 71] 



been brought by man, from distant localities. Prof. 

 Judd inclines to the first opinion. 



The distinctions between these two kinds of stone 

 are well shown by Prof. Gowland : — 



" The large monoliths of the outer circle, and the 

 trilithons of the horse-shoe are all sarsens — sand- 

 stones, consisting of quartz-sand, either fine or coarse, 

 occasionally mixed with pebbles and angular bits of 

 flint, all more or less firmly cemented together with 

 silica. They range in structure from a granular rock 

 resembling loaf sugar in internal appearance to one 

 of great compactness similar to quartzite." 



" The monoliths and trilithons all consist of the 

 granular rock. The examples of the compact 

 quartzite variety were, almost without exception, either 

 hammerstones that had been used in shaping and 

 dressing the monoliths, or fragments which had been 

 broken from off them." 



"The small monoliths, the so-called 'blue stones,' 

 which form the inner circle and the inner horse- 

 shoe, are, with the undermentioned exceptions, all of 

 diabase more or less porphyritic. Two are porphyrite 

 (formerly known as felstone or hornstone). Two are 

 _ /, argillaceous sandstone." 



" . " ^ "" Mr. William Cun- 



nington, in his valuable 

 paper, ' Stonehenge 

 Notes,' records the 

 discovery of two stumps 

 of ' blue stones ' now 

 covered by the turf. 

 One of these lies in the 

 inner horseshoe between 

 Nos. 61 and 62, and 9 

 feet distant from the 

 latter. It is diabase. 

 The other is in the inner 

 circle between Nos. 32 

 and 33, 10 feet from the 

 former, and consists of 

 a soft calcareous altered 

 tuff, afterwards desig- 

 nated for the sake of 

 brevity fissile rock. 



The altar stone is of 

 micaceous sandstone." 

 I now come to the 

 second point, to which I 

 shall return in subse- 

 quent " Notes." 



In studying the 

 material obtained from 

 the excavations, it was 

 found in almost every 

 case that the number of chippings and frag- 

 ments of blue stone largely exceeded that of 

 the sarsens ; more than this, diabase (blue stone) 

 and sarsen were found together in the layer 

 overlying the solid chalk (p. 15). Chippings 

 of diabase were the most abundant, but there 

 were few large pieces of it. Sarsen, on the other 

 hand, occurred most abundantly in lumps (p. 20) ; 

 very few small chips of sarsen were found (p. 42). 

 Hence Prof. Gowland is of opinion that the sarsen 

 blocks were roughly hewn where they were found 

 (p. '40); the local tooling, e.xecuted with the small 

 quartzite hammers and mauls, would produce dust. 



Finally, I reach the third point of importance from 

 the present standpoint; the excavations produced clear 

 evidence touching the mode of erection. Prof. 

 Gowland's memoir deals only with the leaning stone, 

 but I take it for granted that the same method was 

 emploved throughout. This method was this :— 



(i) The ground on the site it was to occupy 

 was removed, the chalk rock being cut into in such a 



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