200 Rev. John Adams — On Sarsen Stones. 



logia"^ 87 years ago, conjectured that the Sarsens in the neighbour- 

 hood of Ashdown Park, were thrown up and scattered over the 

 downs " by an explosion accompanying an earthquake ! " Amongst the 

 peasantry the general belief at the present time, like that of Topsy 

 concerning her origin, is that they grew ; and are as much a natural 

 product of the soil as mushrooms or thistles. 



But what are the opinions of Geologists as to the origin and 

 character of these remarkable stones ? Various theories have from 

 time to time been advanced, but it is now unanimously believed that 

 they are the remains of Tertiary beds which once overspread the 

 Chalk of this district, but which have been broken up and swept 

 away. With regard, however, to the precise series of strata to which 

 they belonged, there are conflicting opinions. 



Mr. Prestwich assigns them to the Woolwich and Eeading beds, 

 i.e. the mottled clays and sands which in this vicinity immediately 

 overlie the Chalk ; and his conclusion is mainly based on this fact, 

 that the sands of that series are of precisely the same mineral cha- 

 racter as the blocks themselves. ''The concretionary stone,"" he 

 says, " in each case represents the component parts of some portion 

 of the Woolwich and Eeading series." 



A tabular mass, apparently in situ, was discovered some years 

 since at Welford Woodlands, near Hangman-stone Lane, in a thin 

 outlier of those beds. It was 10 or 12 feet in width, and lay hori- 

 zontally within a few inches of the Chalk. As its surface was bai-ely 

 plough-deep, it was thought expedient to get rid of it ; and after 

 attempts were made in vain to break it up, a pit was dug on one 

 side of it, into which it was tilted. In making the excavation the 

 edges of three other tabular blocks were laid bare, all lying horizon- 

 tally at the same depth on reddish clay. One of them, which I un- 

 covered a short time since, is of enormous dimensions, being 9ft. Gin. 

 by 9ft. and 25 inches in thickness. A ploughman informed me that 

 in cultivating the field, the surface of others are sometimes touched 

 near the same spot ; and small stones of similar character abound in 

 the vicinity, expecially where pits have been dug for chalk. Masses 

 of similar stone occur also in the same formation at Langley Park, 

 near Beedon, and are resting unquestionably on the very spot where 

 they were consolidated. They are imbedded in sand somewhat 

 stained with oxide of iron, and may be dug out in nodules of all 

 sizes, and of every degree of hardness. Some are so soft that they 

 may be knocked to pieces by a gentle blow of the hammer ; whilst 

 others have the toughness and close-grained structure of the most 

 compact Sarsen. Most of them, however, are coated with sand which 

 is imperfectly solidified, but which gradually merges into the crys- 

 talline character of the block; and the process of agglomeration 

 seems to have been carried on by accretions of pure sand gathering 

 round the mass on all sides. Generally those accretions appear to 

 have taken the form of balls, varying in size from a pea to a walnut ; 

 and they now give a very picturesque asjDect to the stones, causing 

 many of them to resemble huge clusters of Coral. 



^ Vol. viii., p. 442. - Quart. Journ. Geol. Soc, yoI. x., p. 123. 



