TRANSACTIONS OF THE SECTIONS. *]*] 



the gravel-beds of the eocene period were supplied with flints, set free 

 by the solution of the chalk in which they had been formed, and sub- 

 sequently rounded by the action of water. He considered also that the 

 carbonic acid contained in rain-water has produced in more recent 

 periods, and still continues to produce similar effects in corroding and 

 forming cavities on the surface of chalk beneath permeable beds of 

 gravel or sand. 



Exact and beautiful drawings of these appearances at Gravesend 

 were made at the time of their discovery by Mr. Thomas Webster, for 

 Dr. Buckland, and were exhibited at the Section to illustrate his ob- 

 servations. 



On an ceconomical Use of the Granitic Sandstone of North Staffordshire. 

 By Robert Garner, Esq., F.L.S. 



This paper announces the recent discovery of a valuable property in 

 a substance hitherto esteemed worthless. Previously to the last three 

 or four years it has been the practice to import chalk-flints at a great 

 expense into North Staffordshire, for the use of the earthenware ma- 

 nufacture. It has been lately found that the millstone-grit of the Pot- 

 tery district will answer the same purpose, and it is now quarried to 

 the extent of many hundred tons annually. It is found to be a perfect 

 substitute for flint, with the advantage of not requiring calcination pre- 

 viously to being ground. The material for the pottery is compounded 

 of about equal parts of millstone-grit, Dorsetshire and Cornwall clay, 

 and the ware produced is found to possess the qualities of whiteness 

 and compactness in a high degree. The best specimens of millstone- 

 grit are those which contain about three parts of silica and one of alu- 

 mina, and which are free from iron or sulphate of barytes. 



On the rapid Changes which take place at the Entrance of the river 

 Mersey, and the means adopted for establishing an easy access to 

 Vessels resorting thereto. By Jos. Brooks Yates, Esq. 



The author commences this paper with an historical sketch of the 

 changes which have taken place at various times in the sestuary of the 

 Mersey. It appears that at some distant period this sestuary was 

 principally occupied by peat mosses and forests, vestiges of which are 

 still found beneath the sands on the coasts both of Cheshire and Lan- 

 cashire. These mosses appear to have been submerged by an irruption 

 of the sea, which has encroached so much on the land within the last 

 few years as to require the erection of a sea-wall to protect the Leasow 

 lighthouse. 



The changes in the submarine sand-banks are shown by a comparison 

 of ancient with modern charts. From a survey made in 1687 by Capt. 

 Grenville Collins, it appears that large ships were obliged to unload 



