8 Lamplugh : Estuarine Shells at Sand-le-Mere. 



variable in breadth and outline, extending continuously south- 

 westward for seven miles, from the coast-section to the Humber 

 flat near Keyingham. This tract is trenched and rendered 

 cultivable by Keyingham Drain and its branches, and is 

 protected by a bank at Sand-le-Mere from the outer sea which 

 otherwise might invade the hollow during a high stormy tide. 

 It is my impression, however, for reasons hereafter stated, that 

 the estuarine conditions in the hollow were not due to an incur- 

 sion of the open sea, but were developed when the Keying- 

 ham channel formed a long creek of the Humber. 



The exposure that I saw stretched along the foreshore at 

 Sand-le-Mere right across the hollow, revealing the rising slopes 

 of the underlying boulder-clay on both sides. The main strip, 

 containing the estuarine muds, occurred at an average distance 

 of 50 yards from the foot of the raised bank which defends the 

 interior hollow, the length of the bared strip being about 250 

 yards, its width from 5 to 20 yards, and its level approximately 

 that of half-tide, or say 8 feet below high-water. There was 

 also another large patch laid bare on the lower part of the shore, 

 just above low-water (average tide), the intervening space 

 being hidden by sand ; but this lower exposure consisted, so 

 far as I could see, entirely of peat with much wood. Judging 

 from the numerous pholas-borings in it, some containing living 

 occupants, this peat is frequently bare or, at most, thinly 

 sand-covered ; and it is perhaps the only part of the basin 

 which has been previously subject to critical examination. 



In the upper exposure the deposits included some peat, 

 but consisted mainly of soft black, grey and greenish muds 

 and silts in bands, with streaks and thin seams of black muddy 

 sand, these beds dipping gently and thickening from both sides 

 towards the middle of the basin. From the flatness of the 

 exposure combined with the overlapping of the higher beds 

 towards both margins, the sequence and thickness of the 

 deposits were not easy to determine. For me, moreover, their 

 examination was rendered the more difficult by tempestuous 

 rain while I was on the spot, so that only rough notes could be 

 made, and my stay was brief. Hence the information I could 

 gather was incomplete on several points, particularly with 

 respect to the relation of the estuarine muds to the thick peat- 

 bed of the lower exposure. 



Near the northern margin of the alluvial basin, the sequence 

 in the shore-exposure was as follows, in descending order : — 



Naturalist 



