318 PROF. J. B. HARRISON ON [Aug. I907, 



20. The Coral-Rocks of Barbados. By Prof. John Bttrchmore 

 Harrison, C.M.G., M.A., F.G.S., F.I.C., F.C.S. (Read March 



27th, 1907.) 



[Plate XXIII— Map & Section.] 



In the Quarterly Journal of this Society for May 1891 (vol. xlvii, 

 pp. 197-248), Mr. A. J. Jukes-Browne and I published a paper on 

 the coral-rocks of Barbados, and this was followed in the Journal 

 for August 1898 (vol. liv, pp. 540-55), by a paper by Mr. G. F. 

 Franks and myself entitled ' The Globigerina -Marls & Basal Beef- 

 Bocks of Barbados/ in which we described a formation underlying 

 in many places the true coralline limestone, and through which, at 

 Bissex Hill and at Bowmanston, we were able to trace a gradation 

 from Globigerina-Marls to coralline limestones. 



The paper of 1891 was written after I had lived for ten years 

 on the limestone therein described, had visited almost all the 

 sections visible in the island, had descended many wells sunk to 

 the base of the limestone, and had explored all the known caverns 

 traversing that rock. In addition I had spent many hours, both 

 on foot and in my canoe, examining the reefs now in course of 

 formation and the channels between them and the shore in several 

 parts of the island. 



In this paper we specially directed our efforts towards explaining 

 the structural features of the limestone-terraces by reference to the 

 reefs now growing ; we showed the general concordance of the 

 physical features and the parallelism of the older and higher reef- 

 rocks to the lower, and of the latter to those now in course of 

 formation outside the present coast-line ; and we pointed out the 

 causes which, in our opinion, have given rise to them. 



We mentioned (op. cit. p. 197) that the account of the ' Coral- 

 Limestone' of Barbados given by Sir Robert Schomburgk in his 

 ' History ' of that island (1848) ' is fairly complete and accurate ' ; 

 but we did not consider it necessary to repeat in our paper the 

 details so well set out by that author. 



We indicated in the various sections given in the paper the fact 

 that the coral-rocks of the island lie either approximately hori- 

 zontal, or slope at very low angles in various directions. On p. 219 

 of that paper we indicated that 



' near Hillaby Plantation the layers of coral-rock have a distinct westerly dip 

 or slope away from the Hillaby ridge ; the direction varies from a little south 

 to a little north of west, and the angle of slope is about 4°. This inclination 

 is probably due in part to original formation on a slope, but it may have been 

 increased by subsequent upheaval,' 



thus drawing special attention to one of the few places where the 

 •slope of the beds is really well-marked. I regret that we did not 

 specifically mention the practically-horizontal bedding of almost all 

 parts of the coral-rock that we examined, and did not draw attention 

 to the diagonal bedding which in places is shown by the variety of 



