The Rocks of Guernsey

Abstract

A t the opening of this paper I desire to acknowledge my great obligations to Professor Bonney for his assistance throughout my investigations. I must also thank J. R. Cousins, Esq., of St. John’s College, Cambridge, for valuable help. Little has hitherto been written on the geology of Guernsey which would be of much use to a visitor. Macculloch contributed a brief account to one of the earliest publications of this Society. Ansted’s book on the Channel Islands contains some remarks on its general features. There are two papers by Professor Liveing, with which in many respects I cannot agree, in the Cambr. Phil. Soc. Proc. vols. iii. and iv., and one by Mr. J. A. Birds in the Geol. Mag. for 1878, which contains some accurate observations. A few interesting but short papers on raised beaches and the like complete the literature of the subject. How scanty is the information furnished thereby may be imagined from the fact that not one of these publications contains a geological map; and the sketch map (Pl. XX.) which accompanies this paper is, so far as I know, the first which has ever been published. Any map shows clearly enough the triangular shape of Guernsey, and with a glance at the scale of miles its dimensions can be easily estimated. But most maps do not even attempt to indicate the remarkable physical difference between the northern and southern parts. A spectator on the deck of a steamer approaching St. Peter’s Port sees on the

Specialist Maps of the Channel Islands Prepared by German Military Geologists during the Second World War: German Expertise Deployed on British Terrain

“…Despite a similarly long history of geological research (evident from the extensive bibliography provided by Roach et al [1991]), effectively the only geological map for Guernsey as a whole was a diagram ( Figure 5) accompanying reviews of the island's geology by Parkinson and Plymen (1929) and by Plymen (1933), Figure 5. Geological map of Guernsey, from Parkinson and Plymen (1929), based on Hill and Bonney (1884) but with additions: representative of geological mapping of the island available to German military geologists in World War II based largely on an uncoloured 1 : 18 000-scale geological map included as a diagram in an article by Hill and Bonney (1884). Roach (1966, p. 753) was later to claim explicitly that his own postwar geological map of Guernsey at 1 : 25 000 was the first 'to portray accurately the distribution of the major rock types over the whole island'.…”