1871.] HAWKSHAW PEAT-BEDS, HULL. 239 



was supposed to be a coiitimiation of the Hessle bed, whereas the 

 excavations and subsequent borings showed that the Hessle Sand 

 thinned out at the west end of the dock. To the westward of the 

 west end of the dock the peat, Hessle Clay, and Hessle Sand have 

 been removed by the scour of the Humber down to the surface of 

 the Purple Clay, and the more modem deposits of Humber sand 

 and silt repose directly on the latter. In the section in vol. xxiv. of 

 the Society's ' Proceedings,' above referred to, the lower part of this 

 sUt deposit, described as sand in the borings, is, in the writer's 

 opinion, wrongly shown as a continuation of the Hessle-Sand bed. 

 Several borings were made in the foundation for the dock -wall 

 towards the west end of the dock ; the thin bed of Hessle Sand 

 reached by these borings was similar in colour to that found 

 at the east end of the dock, where the Hessle Sand also thins 

 out. As the bed diminished in thickness it became similar in 

 colour to the adjoining clays. Good sections, about 500 feet in 

 length, of the junction of the two clays with the Hessle Sand, the 

 latter reduced to a thickness varying from 2^ feet to 5 inches, 

 were exposed in the excavations for the foundations of the lock 

 at the east end of the dock, which were carried down to the 

 surface of the Purple Clay. Throughout those sections the sand 

 was nowhere absent, and the junction with the two clays was very 

 distinct. "WTiere the bed was thick the sand was of a bright yeUow 

 colour, much cross-bedded, and composed of fine rounded grains of 

 quartz, mixed with a considerable proportion of grains of chalk. 

 This Hessle sand was probably reconstructed out of the Purple Clay 

 in the same manner that the Hessle sand and gravel at Kelsey Hill 

 have, in Mr. Prestwich's opinion, been reconstructed out of the 

 boulder clays. Two sections, each about 1000 feet in length, show 

 accurately the junction of the Hessle Sand and the Purple Clay. 

 There was no intermingling of the sand and clay. The Hessle Sand 

 was removed from the surface of the Purple Clay for the foundation 

 of the dock-walls, for a width of 30 feet along the lines of these 

 sections. The appearance of the surface of the Purple Clay shows 

 it to have been consolidated before the deposition of the sand. A 

 depression about 6 feet in depth, and apparently due to erosion, 

 crossed the section at right augles. On one side the clay formed a 

 steep face ; and the bottom of the hollow was strewed with smaU 

 gravel and scratched and rolled stones. Sometimes boulders were 

 found on the surface of this clay too large to be removed by the 

 current which probably swept the surface of the clay before the 

 deposition of the Hessle Sand. 



The borings taken at the east end of the lock showed the purple 

 clay to be very compact, and free from stones and pot-holes ; these 

 borings were taken to ascertain the source of some springs which 

 burst out in the foundations before the excavations were completed. 

 With one exception, they extended to a depth of 58 feet below high 

 water, nothing but the solid clay being met with below the surface 

 of the Purple Clay. The water from the springs was brackish, and 

 was in all cases charged with from 2 to 5 per cent, of reddish-yel- 



s2 



