34 Mr. P. J. Martin on the Anticlinal Line of 



its more sandy state, or mixed up more or less with angular 

 flints, or as brick-earth clay, has it any of the characteristics of 

 a quiet deposit, — littoral, marine, or lacustrine. It has seldom 

 even the rude multitudinous stratification of more sandy drift. It 

 does not contain any organic remains proper to itself, but now and 

 then only a few broken shells, or perhaps occasionally an entire 

 one derived from the materials of the stratified beds from which 

 it was formed; it is, as I say, neither of marine, nor lacustrine, 

 nor estuary origin, but essentially diluvial. 



1 have already spoken of the manufacture of loam. The ex- 

 pression is not misapplied, for this sort of drift is the handiwork 

 of a powerful and active agency. The question then naturally 

 arises, of what was the source of the materials of so many loams 

 and beds of brick-earth in the district we are reviewing ? The 

 answer is not difficult. The materials of the stratified tertiaries 

 once covering the outlying chalk, to say nothing of those which 

 were spread over tlie chalk of the adjoining downs, were exactly 

 the materials fitted to form these loams and brick-clays. The 

 segregation of the latter here and there into beds of a choicer kind, 

 and the admixture of fewer flints, as may be seen near Shopwick 

 and Ilampnet at Siddlesham, and at Fishbourne brick-yards, 

 supposes nothing more than the existence of breaks in the banks 

 of flint and gravel, or of depressions in the subjacent stratified 

 beds, excavated like the hollows in the sand countries below the 

 chalk, filled up with the slush and turbid waters of the floods, 

 as the sand hollows have been with sand and rubble. 



Boulder drift. — Returning again to the coast-line at Selsey, 

 we have yet to assign its proper place to this deposit. For the 

 present it will be best to speak of it as part of a zone external to 

 that which I have described as tertiary or supracretaceous*. 

 The corresponding parts of this zone are to be found in the val- 

 ley of the Thamesf ; connected with this on the south coast, or 

 in what may be called the Valley of the Solent, by fragmentary 

 remains which may yet be found with the relics of the tertiaries 

 on the Hampshire and Wiltshire chalk. Some of the blocks of 

 stone at Stonehenge are not propei'ly greywethers sandstones; 

 they are crystalline, and could never have been derived from any 

 other source than the erratics of this zone. Professor Ramsay 

 informs me that the inner circles of stone at Stonehenge are of 

 greenstone, and the altar stone is a felspathic trap. This valu- 

 able information is corroborated by reference to an interesting 

 paper from the pen of the Rev. W. D. Conybeare, published in 

 the Gentleman's Magazine for November 1833. Mr. Conybeare 

 does not speak of the altar stone. And there being no better way 



* Phil. Mag. vol. ii. S. 4. p. 285. 



t Lyell's ' Manual of Geology,' p. 132, 5th edit. 



