18. Fibres of a brown colour, with whose, nature I am unacquainted. They are possibly vegetable, but I had not enough to apply the chemical test to the specimen.
19, 20, 21. Were drawn for the purpose of shewing various coloured fibres which are among the most common of those found in chalcedonies. The generally great decision and character of their ramifications seem to establish them as vegetable fibres, and which, as I observed in the paper, have lost their colour by the process of death going hand in hand with their lapidification.
22. Appears to consist of fragments of a lichen of the foliaceous imbricated kind, akin to centrifugus and saxatilis, and bearing a considerable resemblance in colour and general appearance to Parmelia Borreri, as figured in the Linnean Transactions. The fragments are too insufficient in extent, and too deeply bedded in the stone to admit of any very accurate judgment respecting their affinities.
23. Is another example of a moss, apparently of the same family with that figured at No. 7. I have drawn it precisely as it appears. It differs from the former in the more orbicular and obtuse form of the leaves. It is contained in a large nodule of chalcedony, which exhibits much colour and the zonular disposition.
24, 25, and 26. Brown ramified fibres of the same apparent nature as 19, 20, and 21. For these drawings I am indebted to Mr. Blore, and they are from specimens in his possession which I have not had an opportunity of examining very particularly.
27. These are contained in an oriental chalcedony or mocha. They are evidently hollow tubes, of which various aspects are exhibited by the chance section of the stone.
28. Similar tubular bodies which appear equally to belong to the same class of beings. I have figured these because they had been