Changes of Level in the Bermuda Islands. 313 



the advance of those immediately below. There can be little doubt 

 that the fault-slips of 1892 affected the conditions of stress along the 

 neighbouring transverse fault, so that the displacements along it 

 occurred earlier than they might otherwise have done. 



3. ' Changes of Level in the Bermuda Islands.' By Prof. Balph 

 S. Tarr. 



The author gives a summary of previous writings bearing upon 

 the geology of the Bermudas ; but his own researches point to 

 a rather more complicated series of changes than those which have 

 been inferred by other writers. The formation of the ' base-rock ' 

 or ' beach-rock ' occurred at some period which cannot be accurately 

 ascertained at present, owing to the fragmentary nature of the 

 included fossils. It may have been formed in Pleistocene or even 

 late Tertiary times. After its formation it was converted into a 

 dense limestone and then eroded, probably by subaerial agents, and 

 finally attacked by the waves at an elevation of at least 15 feet 

 above present sea-level ; during this stage it was covered by beach- 

 deposits of pebbles and shells, which were accumulated in a period 

 so recent that the contained fossils are of the same species as the 

 organisms living in the neighbouring sea. Then followed an 

 uplift, during which land-shells lived on the beach -deposits ; but 

 these were soon covered by blown sand — the principal accumulations 

 of the islands, and the outline of the islands was perfected by the 

 action of the winds. This was done at an elevation which was at 

 one time certainly as much as 40 or 50 feet above present sea- 

 level. The author adduces evidence of a depression since this 

 accumulation, causing land to disappear and the outline of the area 

 to become very irregular ; and he proves that these changes cannot 

 be accounted for solely by erosion, as some have maintained. There 

 are indications that the land is at present quiescent. It appears, 

 then, that most of the work of construction of the Bermudas has 

 been done in recent times. 



January 20th. — Dr. Henry Hicks, F.R.S., President, 

 in the Chair. 



The following communications were read: — 



1. ' On Glacial Phenomena of Palaeozoic Age in the Yaranger 

 Fiord.' By Aubrey Strahan, Esq., M.A., F.G.S. 



The Gaisa beds of the Varan ger Fiord consist of slightly 

 altered quartz-grits, with red sandstones and shales, and rest 

 upon a deeply denuded surface of the metamorphic rocks. In 

 a section, first noticed by Dr. Reusch, a heterogeneous mixture 

 of grit and clay with boulders of granitic and other rocks is 

 seen to be intercalated between the quartz-grits, the bedding of 

 the overlying grit proving that this boulder-rock was contem- 

 poraneously formed, and not subsequently wedged in. The surface 

 of the grit below the rock is characteristically glaciated. Proof 

 is given that the striated surface is not the floor of a thrust-plane, 



Phil. Mag. S. 5. Vol. 43. No. 263. April 1897. 2 B 



