128 Notices of Memoirs — T. M. Mall on Limdy Island. 



seem to have followed the directions of the greater valleys, whether 

 east, south-east, south, or S. 20° W. Along the sea-shore are marine 

 dejjosits of the Champlain or Post-Pliocene period. 



The meteorological work consisted in the establishment of an ob- 

 servatory, during the winter of 1870-71, upon the summit of Mount 

 Washington, 6293 feet above the sea, the station being subsequently 

 adojDted by the " Signal Service of the War Department " of the 

 General Government. The experiences of the party resembled 

 greatly those reported by explorers in the Arctic zone. The observa- 

 tions were reported daily for the press, and have been printed in the 

 Geological Keport for 1870, as well as a popular account of the 

 writer's experiences, entitled "Mount Washington in Winter." Boston. 



II. — Notes on the Geology and Mineralogy of the Island of 

 LiJNDY. By TowNSHEND M. Hall, F.G.S. 

 [Transactions of the Devonshire Association for 1871.] 



REFEREING first to previous geological observations on the 

 Island, the author then describes its Physical Geography and 

 Geological Structure. 



The principal part of Lundy Island is composed of granite, the 

 south-eastern corner, however, consists of slate. In their petrological 

 characters, as well as in their general appearance, these silvery slates 

 closely resemble those of Ilfracombe or Morthoe in the North Devon- 

 ian group. Judging, however, from the general east and west 

 strike of the North Devon series, these Lundy Island slates would 

 naturally come on the horizon of either the Pilton-beds (ujopermost 

 Devonian), or the Carboniferous shales (or Culm-measures) of the 

 mainland, which Mr. Hall regards as occupying a position between 

 the Devonian and the Millstone Grit. No fossils having hitherto 

 been discovered in Lundy, it is found most difficult to prove to which 

 of the two systems the slates should be referred, especially as in 

 North Devon the two great systems (as Mr. Hall remarks) pass quite 

 insensibly one into the other, without any distinct line of separation 

 between them^a fact of great importance in the grand Devonian 

 question. 



That the slates of Lundy existed before the intrusion of the granite 

 is shown by the very abrupt manner in which they are cut off by it. 

 The granite is generally similar to the other isolated masses of the 

 same rock in the west of England. Schorl is not abundant as a 

 component, but there are occasionally thin irregular veins of a fine 

 grained granitic substance (eurite?) traversing the rock. Many years 

 ago the Eev. D. Williams described the granite of Lundy as occupy- 

 ing a dyke having a north-east and south-west direction, having a 

 similarity, as regards mode of occurrence, to the little patch of 

 granite or syenite which Mr. Leonard Horner first pointed out at 

 Hestercombe, near Taunton, 69 miles distant. These granites are 

 therefore different from the "domes" or larger masses in Devon and 

 Cornwall. Mr. Hall discusses the connection which has been sup- 

 posed to exist between these two granitic dykes. Their eruption he 



