ON THE EROSION OF THE SEA-COASTS OK ENGLAND AND WALES. 383 



Report by Captain C. E. Salvesen, R.E., July 1892. Communicated hy 

 the Director-General of the Ordnance Survey. 



In accordance with the Director-General's instructions, dated May 9, 18!I2, 

 I now forward 6-inch sheets lli3, 180, and 197, on which have been accurately 

 drawn from the new ttijoo pl'i^s (surveyed in 1890) the ' top of cliff 'K.W.M. O.T., 

 L.W.M. O.T., extent of shingle, groynes, new beach marks and levels, and otiier 

 details that I consider will be useful in the question of erosion. 



All additions to the (i-inch sheets named, with the exception of L.AV.M. O.T. 

 (which is shown by a black line edged with blue), have been inserted in red. 



The total length of the coast lines on 6-inch sheets 163, 180, and 197 is 12 miles 

 .fi6 chains, and the total erosion from old top of cliff to new top of cliff is in this 

 distance 204-026 acres, giving an average width to the strip of coast removed of 

 132-5 feet. Taking the total time as forty years (6-inch sheets surveyed 18.50-52, 

 23'ou plans in 1890), the yearly rate of erosion comes to about 3 feet 3^ inches. The 

 actual areas for separate sheets are as follows, viz. — 



Yorkshire 6-inch sheet 163 . . . 59147 acres "1 giving average width of strip 

 1«0 . . . 59-593 „ J =118-86 feet. 



197 . . . 85-286 „ do. 157 67 „ 



Total 204-026 



The last result— viz., 157-67 feet— disagrees slightly with that arrived :it bv 

 Captain Kenney, R.E. ; but his was only the average of four measurements, wlncli 

 would hardly give such an accurate result. 



I have in each case calculated the area from old top of cliff to new top of ctilf 

 as this represents the amount of land that is or probably could be put under 

 cultivation. 



The average height of the cliffs in 6-inch sheets 163, 180, and 197 is 39-34 feet. 



This result has been arrived at by computing the area of an elevation (if the 

 coast-line made from data on the 6-inch sheets and new ;;^ sheets (B.M.'s pickets 

 and contours) and dividing by the total length of coast— viz., 12 miles 5(1 ciiuius. 

 Multiplying the average width (132-5 feet) by average height (39-34 feet) and total 

 length (12 miles 56 chains), the result is 12,955,666 cubic yards of material washed 

 away in forty years, or an average of 25,503 cubic yards per mile per annum. 



Report hy Captain "VV Russell, R.E., July 1892, 



I forward herewith (Yorkshire) 6-inch sheets 47, 62,77, 78, 94, 110, 111, 128. 

 129, and 146, on which have been shown the present high and low-water mark of 

 ordinary tides as obtained by the revision of the survej', and al.so any alterations in 

 the line of the tops of the cliffs. 



From these it will be seen that the only place where the erosion has been at all 

 serious is at and south of Bridlington, and also just south of Filey. 



All the rest of the coast being high cliffs, the action of the sea has been very 

 slight, and indeed along the greater portion there is no appreciable difference 

 between the old and new surveys. I also forward a report from T. C. A. Crcok, who 

 has been in charge of the revision of the whole of the coast from Bridlington to 

 Whitby, in which he replies categorically to the questions asked. 



The revision of the coast has as yet only been completed as far north as Whitbj', 

 and beyond that town I am not able to afford any reliable information. 



The distances between the old and new lines of the top of the cliff at various 

 places have been measured on the 6-inch plans, and are approximately given in feet 

 for purposes of comparison in the attached list. 



1. — That portion of the east coast lying between Bridlington Quay and Wliitby. 



2. — It is composed principally of rock and chalk cliffs interspersed with sandy 

 bays, these latter being usually bounded by cliffs of alluvial soil. The whole of 

 the line of clifE from Bridlington to the Humber consists of a varying cliff of 

 brown unstratified clay and gravel from 20 to 50 feet high, the average probably 

 about 25 feet. From Bridlington northwards to Speeton the cliffs are of cha!k, 

 forming the eastern boundary of the Yorkshire Wolds. These range in heieht from' 

 50 feet at Bridlington to near 400 feet at Speeton ; the average will probably be 

 about 200 feet. Continuing northwards from Speeton to Filey, the cliffs are formed of 

 boulder clay, and are of a pretty uniform height, averaging 100 feet. From Filey to 



