82 



fifty islets, lying within a space of fifteen miles by five, and situated 

 on the S.E. side of a zone of coral reefs, approximating in form to 

 an ellipsis, the major axis of which is twenty-five miles and the mi- 

 nor thirteen. The highest point is stated to be Sears Hill, 260 feet 

 above the level of the sea; and the undulating portions of the islands 

 are described as resembling sand-hills in shape, and chalk downs 

 in colour. 



The whole group is composed of calcareous sand and limestone, 

 derived from comminuted shells and corals, and the different va- 

 rieties are associated without any definite order of position, the 

 harder limestones occasionally resting upon loose sand. The ar- 

 rangement of the beds is often domed-shaped, but in many instances 

 the strata are singularly waved. 



The bottom of the basin within the zone of coral reefs is stated to 

 consist of corals, calcareous sand, and soft calcareous mud resem- 

 bling chalk, and considered by the author to have been derived 

 from the decomposition of Zoophytes. 



Under the head of encroachments, he describes the banks of 

 detritus thrown up by the sea, and the progress which, under 

 certain circumstances, the loose sand makes in overwhelming tracts 

 previously fertile. He states that wherever the shrubs and creepers 

 have been destroyed, the sand has spread rapidly, but that it is inva- 

 riably stopped as soon as it arrives at a plantation or row of trees. 



The shells found by the author in the sand as well as the lime- 

 stone, belong entirely to recent species, the most abundant being 

 the Veiius Penst/lvanica, which in some of the islands constitutes 

 entire beds. The only vegetable remains which he observed were 

 casts of the root of a plant considered by the natives to belong to 

 the palmetto which now grows upon the island. 



Caverns are stated to be very numerous, and their origin is as- 

 signed to the undermining action of the sea. 



The memoir concludes with an account of the method by which 

 the author conceives coral islands and reefs are formed. 



May 7. — Richard Prime, Esq., of Walburton near Arundel; 

 William Henry Breton, Esq., Lieut. 11. N. ; Edmund Buxton, Esq., 

 of Devonshire Place; and Capel Cure, Esq., also of Devonshire 

 Place, were elected Fellows of this Society. 



A paper was first read, " On the Distribution of Organic Remains 

 in the Lias Series of Yorkshire, with a View to facilitate its Iden- 

 tification by giving the Situation of its Fossils," by W, Williamson^ 

 jun., Esq. of Scarborough. 



The part of the Yorkshire coast to which this paper immediately 

 refers, extends from the Peak Hill near Robin Hood's Bay to the 

 village of Saltburn near Redcar. The lias presents the threefold 

 arrangement of alum-shale, marlstone, and lias marl or lower lias 

 rock. 



The first of these deposits, the author says, consists of three di- 

 stinct divisions, viz. (a) soft, rubbly shale 130 feet thick, (b) hard 

 shale breaking into large lamellar blocks, 30 fe^t thick, and (c) soft 

 sandy shale from 15 to 20 feet thick. The upper part of the su- 



