The favourable reception of these desultory "_Thoughts_" which were originally penned for the amusement and instruction of an intelligent boy, is a gratifying proof that the attempt has not been unsuccessful; and I would fain indulge the hope, that this "_First Lesson in Geology_" may still be productive of good, by exciting in some youthful minds a desire for the acquisition of natural knowledge; and inculcating the important truth, that He who formed the Universe has created nothing in vain; that His works all harmonize to blessings unbounded by the mightiest or most minute of His creatures; and that the more our knowledge is increased, and our powers of observation are enlarged, the more exalted will be our conception of His wondrous works. Chester Square, Pimlico. CONTENTS. Page. Thoughts on a Pebble: Part I. 5 More Thoughts on a Pebble: Part II. 33 "The Nautilus and the Ammonite" 57 Supplementary Notes 61 Note I. _Shells in Chalk_ 61 ---- II. _Wood in Flint_ 66 ---- III. _Whitby Ammonites_ 69 ---- IV. _Fossil Nautili_ 72 ---- V. _Brighton Cliffs_ 75 ---- VI. _Rotaliæ in Chalk and Flint_ 79 ---- VII. _Isle of Wight Pebbles_ 82 ---- VIII. _Zoophytes of the Chalk_ 87 ---- IX. _Minute Corals from the Chalk_ 92 ---- X. _Infusorial Earths_ 97 LIGNOGRAPHS. Page. 1. Vignette of Title-page. 2. Fossil Turban-echinus (_Cidaris_), with spines. 9 3. Bivalve with spines (_Plagiostoma spinosum_) in chalk; from Lewes. 11 4. Teeth of several species of the Shark tribe, in chalk; from Lewes. 12 5. Chalk-dust highly magnified, consisting of minute shells. 13 6. Shells (_Rotaliæ_) from the chalk, highly magnified. 14 7. Ammonite (_A. communis_) from the Lias, at Whitby. 20 8. Nautilus (_N. elegans_) from the chalk-marl, Lewes. 22 9. View of the Cliffs east of Brighton. 27 10. Fossil animalcules (_Xanthidia_) in flint. 35 11. _Xanthidium palmatum_, in flint. 37 12. Rotalia in flint. 39 13. Minute scales of fishes in flint. 40 14. Choanites from the chalk; near Lewes. 44 15. A branch of fossil coral attached to the pebble 46