It is many years ago since Sir Archibald Geikie pointed out that the Tertiary basalts of the Western Isles of Scotland and North-East Ireland were remnants of plateaux built up of lavas extruded from fissures after the manner described by von Richthofen. In historic times fissure eruptions have taken place in Iceland, and in The Ancient Volcanoes of Great Britain a chapter is included on “The Modern Volcanoes of Iceland as illustrative of the Tertiary Volcanic History of North-Western Europe” (1, p. 260). Whilst little remains to be added in support of the very definite analogy exhibited in the nature of the lava streams themselves, the equivalent of the thin bands of red rock so typically intercalated in the Tertiary series has not been particularly examined, and I have visited Iceland in order to study the red beds themselves and search for their counterparts in the modern lava deserts.

I have been studying the zones of the Upper Jurassic clays for the last seven or eight years. Repeated delays from various causes have already diminished the value of the results, and as the work is now held up indefinitely it seems advisable to publish a summary of the conclusions to which I have come, in case the completion of the work may fall to other hands. Such a summary must necessarily be much more dogmatic than I could wish. I have to acknowledge my very great indebtedness, both direct and indirect, in connexion with this work, to Mr. S. S. Buckman.

In a paper on the Permian formation in the Maritime Alps, etc. (Geol.Mag., 1916, pp. 7–17), I mentioned incidentally that it extends from those Alps, viz. from the Montgioie range east into Liguria as far as the Savona Hills. As in the former so also in the latter region, that formation is composed of essentially gneissic schists known as apenninites or besimaudites belonging to the Lower Permian or Permo-Carboniferous, and of sericitic schists, quartzites, and clastic rocks or ‘anagenites’ which constitute the Upper Permian or Verrucano proper, forming a transition to the Lower Trias. The geological limit of the Permian in the Savona Hills coincides more or less with the geographical line of division of the Alps and Apennines at the Colle or saddle—also called Bocchetta—d'Altare; but another geological line of division exists still further east, at the junction of the Triassic and Eocene formations in the Chiaravagna Valley near Sestri Ponente, immediately west of Genoa. In reality the geological division is marked, not by either of those lines but by a contact-zone between them. This contact-zone occupies the whole of Western Liguria and comprises two distinct and dissimilar parts: one, the Triassic calc-schists and pietre verdi area or Voltri group, which extends for about 25 kilometres along the Riviera littoral west of Genoa from Sestri Ponente to Voltri, Varazze, and Celle Ligure, and the other or Savona group, which skirts the littoral for about 15 kilometres from Celle to Savona and Zinola, and is composed for the greater part of a crystalline massif of granitic, gneissic, and amphibolic rocks.

This district is of especial interest from the palæontological point of view in that the different members of the Upper Trias each afford a representative though not extensive flora and fauna. The scantiness of the material, in so far as the Lower Keuper and in some respects the Dane Hill Series are concerned, is due rather to the absence of good sections. This cannot, however, be said of the Rhætic beds, for the section at Glen Parva is one of the finest in the Midlands.

This footprint was noticed by Mr. A. R. Horwood in the British Association Trias Committee's Report for 1909 (5) and there referred to as resembling Cheirotherium herculis (Eg.) and to be from the Lower Keuper Sandstone. As mentioned in that note, it was found in an excavation at Kegworth, North Leicestershire, some thirty-four years ago by Mr. J. Large, who in 1909 presented it to the Leicester Corporation Museum. It is interesting as being the only Chirosauroid print so far recorded from the Keuper rocks of Leicestershire, and proves the occurrence in that area of animals and conditions similar to those which existed in Cheshire, Staffordshire, and Warwickshire during the Keuper period.