clayey

savinen

savipitoinen Resembling or containing clay.
1812, Antonio de Alcedo and George Alexander Thompson (translator), The geographical and historical dictionary of America and the West Indies, vol. 2, http://books.google.co.uk/books?id=yGQFAAAAQAAJ&pg=PA13&dq=clayey&ei=vNzYSY3ADYWoNurZ2PsC page 13, “Demerara” (J. Carpenter):

The shores of the rivers and creeks are chiefly planted with coffee, to the distance of about 30 miles from the sea : thence 30 miles farther up, the soil becomes clayey and more fit for sugar-canes.

Because no man can ever feel his own identity aright except his eyes be closed; as if, darkness were indeed the proper element of our essences, though light be more congenial to our clayey part.

Limestone, of course, is calcium carbonate, and thus chemically utterly different in composition from the clayey rocks below and the hard, pebbly ones above.