During the long period of time comprised in the history from the Cambrian Period onwards, the slow and persistent evolution of plant and animal life went forward and left ample record in the rocks. To warrant a belief in organic evolution, we are no longer solely dependent on reasoning founded on existing organisms or on the facts of their ontogeny and distribution. As M. Marcellin Boule says in his work on Fossil Man, “… pour tout ce qui a trait à l'évolution des êtres organisés en général, le dernier mot doit rester à la Paléontologie quand cette science est en mesure de parler clairement. Les plus fins travaux anatomiques, les comparaisons les plus approfondies, les raisonnements les plus ingénieux sur la morphologie des êtres actuels ne sauraient avoir la valeur démonstrative des documents tirés de la roche où ils sont enfouis et disposés dans leur ordre chronologique même.” Although we are only too painfully aware of the innumerable chances that conspire to prevent an animal or plant from securing immortality by preservation as a fossil, the finding of better preserved material, the more skilful preparation of it for examination, and the application to it of refined biological methods, such as careful dissection and the serial sections of Professor Sollas, are giving us more complete and accurate knowledge than ever before. It may now be confidently stated that many of the most crucial links in the chain of evolving life are in our hands, that they actually lived in the past, and that their fossil forms show their relationship to their predecessors and successors. The time has come when Darwin's famous chapter on the “ Imperfection of the Geological Record ”, an apology written with the most balanced criticism and unbiassed judgment, should be re-written and revised.

An examination of sections of the silicified wood from the King's Arms Pit, Tiptree, revealed at once that the structure was of the Dadoxylon type, and the absence of growth rings strongly suggested affinity with the Palaeozoic woods included in that genus, many of which are allied to Cordaites rather than to the araucarians. Among known silicified woods, a close comparison was possible only with those from the Corley (Enville) Group of the Midlands, now regarded as probably Upper Carboniferous, and not Permian.

The fragment of silicified tree stem identified in the preceding paper by Mr. W. N. Edwards as a Dadoxylon from the Upper Carboniferous of Warwickshire was found in the gravel pit at Tiptree Heath just west of the King's Arms. This pit is at 269 feet above sea-level on the summit of the ridge that runs from Wickham Bishop, towards Colchester. The gravel is part of an extensive sheet which is shown on the Geological Survey Map (sheet 47) as Glacial Gravel. Dr. A. E. Salter (Proc. Geol. Soc., xix. 1905, p. 31) recorded from this pit Bunter debris, sarsens, radiolarian chert, rhyolite, and the green ash associated with it, and Carboniferous chert, with crinoids.

In Appendix I to the Summary of Progress of the Geological Survey for 1921, pp. 118–28, “The Retreat of the Lake District Ice-cap” is dealt with.

The Ballachulish “ granite ” has been well known to petrologists for many years through the writings of Sir J. J. H. Teall, while more recently Mr. E. B. Bailey has described both the igneous rock and its associated contact phenomena in the Geological Survey Memoir for Sheet 53 (Scotland).