66 



tlie beds local names, thus, in ascending order, the grey chalk and 

 chalk ■without flints, sometimes called the lower chalk, he names 

 the Folkestone chalk. The chalk with but few flints and large 

 ammonites, the Dover chalk. A grey bed of chalk with organic 

 remains, the St. Margaret's chalk. The chalk containing numerous 

 bands of flints, constituting the Ramsgate cliff's, the Eamsgnte 

 chalk. The higher bed containing, like the lower chalk, but few or 

 no flints, Mr. Eowker calls the Margate chalk. The natural 

 joints of this rock are very conspicuous in the Margate cliff's, run- 

 ning like those I have noticed in the oolite in a south-easterly and 

 south-westerly direction, and which the waves have enlarged into 

 the caverns that lend a certain picturesqueness to this part of the 

 coast, that lacks the height and rich- colouring of the nobler cliff's of 

 Folkestone. 



As in a cathedral, the S'orman and Early English styles pre- 

 ceded the Perpendicular, so the primary and secondary were suc- 

 ceeded by the tertiary forms of life. Ihe chalk closes the reptilian 

 or secondary age. I^ew forms of animal life make their appear- 

 ance in the period that follows, which, for the sake of convenience, 

 has been divided into the lower, middle, and upper tertiary, some- 

 times spoken of as the Eocene, Miocene, and Pliocene. The low- 

 est member of the Eocene, locally known as the Thanet sands, in 

 some places penetrates into the chalk where the latter has by 

 chemical action been dissolved away through water percolating 

 from above, and so forming the sand pipes and irregular hollows, 

 showing so conspicuously in section at the sides of railway cut- 

 tings through the chalk. At the base of these Thanet sands is a 

 stratum of tabular aud green-coated flints, the green colour of the 

 latter being due to protosilicate of iron, which also communicates 

 the same tinge to several of the beds, thus forming tertiary green- 

 sands. Mr. Whitaker, the great authority on the lower tertiaries, 

 in a paper published with the proceedings of the Geological Society 

 for 1886, suggests that this bed may even have been formed after 

 the upper ones were deposited by the dissolving away of the chalk, 

 as the contained flints are not water-worn. It is seldom five feet 

 thick. In agreement with an opinion expressed by Mr. Dowker in 

 his lecture on flints, quoted in my last paper, the former authority 

 mentioned a green-coated flint having been found partly enclosed iu 

 a brown tabular flint, showing that the latter must have been 

 formed subsequently. A succession of loamy beds then occur, 

 followed by sands containing green gi-ains. As these green sands 

 weather on exposed surfaces to a reddish brown, they aie apt to 

 escape observation. When the oxidised surface is removed, the 

 original colour becomes apparent. The upper beds at Eeculver are 

 fine grained sands hardened into sandstone, often stained with 

 markings of oxide of iron. Mr. Dowker, in a paper published in 

 The Geologist for 1861, page 110 aud 213, gives a section of the 



