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 archæological inquiries conducted in the same year should have come so nearly to the same conclusion. 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 " To describe their geological character, I cannot do better than quote, from Mr. Cunnington's "Geology of Stonehenge, their origin according to Prestwich:

"Among the Lower Tertiaries (the Eocene of Sir Charles Lyell), are certain sands and mottled clays, named by Mr. Prestwich 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, DATUM LINE A B C D E F

"The small monoliths, the so-called 'blue stones,' which form the inner circle and the inner horseshoe, are, with the undermentioned exceptions, all of diabase more or less porphyritic. Two are porphyrite (formerly known as felstone or hornstone). Two are G H

101 2 EEET

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 the 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, represent boulders of the Glacial drift, or they must have 1 Hills Archaeological and Natural History Magazine, xxi. pp. 141-149

FLINT IMPLEMENT SARSEN HAMMERSTONE

argillaceous sandstone.'

"Mr. William Cunnington, 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 designated 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 subsequent "Notes."

In studying the material obtained from the excavations, it was found in almost every case that the number of chippings and fragments of blue stone largely exceeded that of the sarsens; more than this, diabase (blue stone) and sarsen were found together in the laver 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, executed 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 employed throughout. This method was this:

(1) The ground on the site it was to occupy was removed, the chalk rock being cut into in such a

manner as to leave a ledge, on which the base of the stone was to rest, and a perpendicular face rising from it, against which as a buttress one side would bear when set up. From the bottom of this hole an inclined plane was cut to the surface, down which the monolith which had already been dressed was slid until its base rested on the ledge.

(2) It was then gradually raised into a vertical position by means first of levers and afterwards of a ropes. The levers would be long trunks of trees, to one end of which a number of ropes were attached (this method is still employed in Japan), so that the weights and pulling force of many men might be exerted on them. The stronger ropes were probably of hide or hair, but others of straw, or of withes of hazel or willow, may have been in use for minor purposes.

(3) As the stone was raised, it was packed up with logs of timber and probably also with blocks of stone placed beneath it.

(4) After its upper end had reached a certain eleva

GEOLOGY OF THE MOON.

FOR many years past geologists have turned wistfully to the moon in the hope of gaining from a study of its surface some insight into planetary evolution, and more especially into some of the stages in the history of our own globe. It must be confessed, however, that as yet few satisfactory data have been obtained, either in the facts observed or in the deductions drawn from them. The great majority of those who have studied the subject have formed the opinion that our satellite was once a liquid mass, such as we believe the earth itself to have also been, and that its so-called "craters" represent extensive and prolonged volcanic activity, when the gases and lava of the heated interior escaped to the surface, probably on a scale of magnitude greatly surpassing that on which subterranean energy has ever been manifested in the geological history of our planet. But another explanation has been proposed for these lunar features. according to which, as worked out by Mr. G. K.

tion, ropes were attached to it, and it was then hauled by numerous men into a vertical position, so that its back rested against the perpendicular face of the chalk which had been prepared for it. During this part of the operation, struts of timber would probably be placed against its sides to guard against slip.

As regards the raising of the lintels, and imposts, and the placing of them on the tops of the uprights, there would be even less difficulty than in the erection of the uprights themselves.

It could be easily effected by the simple method practised in Japan for placing heavy blocks of stone in position. The stone, when lying on the ground, would be raised a little at one end by means of long wooden levers. A packing of logs would then be placed under the end so raised, the other extremity of the stone would be similarly raised and packed, and the raising and packing at alternate ends would be continued until the block had gradually reached the height of the uprights. It would then be simply pushed forward by levers until it rested upon them.

I shall deal later on with several interesting conclusions to which these investigations lead. NORMAN LOCKYER.

Gilbert, of the United States Geological Survey, the moon was formed by the aggregation of a ring of meteorites which once encircled the earth, and the "craters," instead of arising from the escape of volcanic energy from within, were produced by the impact of the last meteoric bodies that fell from without. These bodies, arriving with planetary velocity, would be melted or reduced to gas, while a portion of the lunar surface around them would also be liquefied. Mr. Gilbert believes that the lunar topography bears witness to such a meteoritic bombardment rather than to gigantic volcanic explosions. The latest contribution to the discussion was recently presented to the Academy of Sciences of Paris by MM. Loewy and Puiseux. These eminent astronomers direct attention to the evidence furnished by the latest photographic charts of the "Atlas Lunaire" in regard to the conditions in which a planetary body passes from the liquid to the solid state, and to the stage in this transformation which has been reached respectively by the earth and the moon.

With respect to the evolution of the earth two opposite theories have been propounded. The great body of geologists have maintained that the interior

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