The Coral-Rocks of Barbados, 763 



slates with true crystalline schists. But, without going into the 

 details of sections, he shows from general reasoning that both the 

 kind and the amount of transport, postulated by Prof. Lugeon, 

 introduce serious mechanical difficulties. Sediments are assumed to 

 have been transported from (say) near Ivrea to the northern margin 

 of the Alps on either side of the Rhone valley below Martigriy ; 

 that is, to have travelled something like 75 miles. As the average 

 thickness of the Secondary and older Tertiary strata in this part of 

 the Alps can hardly exceed 2*5 miles, we can form a general idea 

 of the problem by drawing an oblong 30 times as long as high. Then, 

 material at one end (southern) has to be squeezed across obstacles 

 to near the other, by piling a wedge-like mass of sediment on a 

 southern prolongation of the oblong, the thin end of which mass 

 may perhaps trespass a little on the northward side of the original 

 southern boundary. 



After discussing the problem in some detail, the author shows 

 that in Prof. Sollas's experiments there was, at the beginning of 

 loading, a wedge instead of an oblong ; the distance to be traversed 

 was 6 times the maximum thickness of the (supposed) sedimentaries, 

 instead of about 30 times ; and the slope of the added mass was about 

 double that which, in the Alpine case, is supposed to be the sole 

 cause of the movement. Lastly, in the case which presents by far 

 the greater difficulties, the material is limestone and shale instead 

 of cobbler's wax. The author maintains that Prof. Lugeon's hypo- 

 thesis receives no real support from Prof. Sollas's experiments, and 

 involves mechanical difficulties which are practically insuperable. 



2. ■ The Coral-Rocks of Barbados.' Bv Prof. John Burchmore 

 Harrison, C.M.G., M.A., F.I.C., F.G.S. 



The results of the author's extended, and in many places detailed, 

 re-examination of the coral-rocks in the southern half of Barbados, 

 give no support to Dr. J. W. Spencer's theory of the existence of 

 strata of the l Antigua Formation ' in that island. It is now shown 

 that a certain knoll, whence Dr. Spencer collected corals which in his 

 estimation proved that it and other parts of the coral-rocks were of 

 Oligocene age, is in part made up of corals which, as stated by 

 Prof. J. W. Gregory, ' certainly show no evidence of any age 

 greater than the Pleistocene.' The author has failed to find any 

 signs of the widespread formation, described in Dr. Spencer's paper 

 as extending from Mount Misery to near Ragged Point, a distance 

 of about 11 miles, and dipping south-eastward at from 12° 

 to 20 c . Such a formation would be about 15,000 feet thick ; 

 while the facts that nowhere in the island does the combined 

 thickness of the limestone and of its basal or Bissex Beds exceed 

 280 feet, and that the limestone is not traversed by faults, are 

 fairly-conclusive evidence of the non-existence of such a formation. 

 This dip is referred to the action of landslips in some cases, and in 

 others to current-bedding. The author's recent investigations have 

 confirmed the statements made and the views expressed by Mr. Jukes- 

 Browne and himself, in the notes published in the ' Geological 

 Magazine ' for December 1902, p. 550. 



