Transcriber Note: Text emphasis denoted as _Italics_. [Illustration: Frontispiece] A MONOGRAPH OF THE TRILOBITES OF NORTH AMERICA: WITH Coloured Models of the Species. Multa renacentur quæ jam cecidere.--Hor. BY JACOB GREEN, M. D. Professor of Chemistry in Jefferson Medical College. ·—▸⏵►●◓●◄⏴◂—· PHILADELPHIA: Published by Joseph Brano, No. 12, Castle Street. Clark & Raser, Printers. 1832. Entered according to the Act of Congress, in the year 1832, by Joseph Brano, in the Clerk's Office of the District Court of the Eastern District of Pennsylvania. To JOHN GEORGE CHILDREN, Esquire, F. R. S. L. & E. The kindness which a traveller receives when in a distant land, must ever be among his most pleasing recollections your attentions therefore to me, during any short residence in London a few years since, cannot easily be forgotten. Suffer me, then, to inscribe this little work to you as a token of my gratitude. Our pursuits in the Natural and Physical Sciences have been congenial. Your interesting researches with your original and magnificent Galvanic Battery, first drew my attention to the calorific effects of that mysterious agent; and your works on Natural History have stimulated my exertions in the same fascinating pursuit. A large portion of your time and fortune have been devoted to the patronage or the cultivation of Natural Science so that the dedication of this work to you, if it were infinitely more worthy of your acceptance, would be due from me, both as a tribute of high respect, as well as of grateful acknowledgment. _Philadelphia, October 1st, 1832._ EXPLANATION OF THE PLATE. Figure 1. Trimerus Delphinocephalus. 2. Calymene Diops. 3. Asaphus Micrurus. 4. Cryptolithus Tessellatus. 5. Paradoxides Boltoni. 6. Triarthrus Beckii. 7. Isotelus Cyclops. 8. Dipleura Dekayi. 9. Head of D. Dekayi. 10. Ceraurus Pleurexanthemus. The above figures represented on the Frontispiece to this volume, were first published in the Monthly Journal of Geology, &c. for June, 1832, and I am indebted to C. A. Poulson, Esq., for the use of them in this Monograph. INTRODUCTION. —————