Keywords: Transactions of the Geological Society, 1st series, vol. 4 figure page 0506-0507.png Transactions of the Geological Society Google http //books google com/books id 1ybPAAAAMAAJ and http //books google com/books id hrcQAAAAIAAJ Collective works 1817 PD-old Transactions of the Geological Society of London 1st series vol 4 |