CEETAIX MYE.R-VALLEYS IN LINCOLNSHIRE. 605 



on almost every point which he has raised in his recent memoir*. 

 Belinquishing his older opinions regarding the formation of Boulder- 

 clays, he has adopted the theory of their terrestrial origin, and .finds 

 evidence of a theoretical ice-cap where other eyes can only see the 

 results of ordinary rain- and river-erosion. He even goes so far as 

 to doubt the capacity of certain rivers to make their own valleys, and 

 does not believe that the rivers of Lincolnshire or East Angiia " had 

 anything to do with the excavation " of the valleys in which they 

 flow. He prefers to attribute the excavation of these valleys to the 

 rush of waters produced by the melting of a mass of ice on the top 

 of the chalk escarpment in Lincoln and Norfolk. 



To any one familiar with the work of rain and rivers such an idea 

 must seem highly improbable, and to any one who can visit the valley 

 of the Steeping, and will note the wonderful series of dales, 

 combes, and hollows which have been fretted out of the edge of the 

 Lower jSTeocomian sandstone, and which are so evidently due to 

 the action of rain and springs, Mr. Wood's hypothesis must seem 

 extremely unlikely and utterly unnecessary. A mere inspection of 

 the Geological Survey map, in fact, will afford sufficient grounds 

 for deciding between the two explanations. 



Mr. S. Y. "Wood confuses the two distinct valleys of the Bain 

 and Steeping with the general trough-line in which they lie, and 

 which he calls the Bain-Steeping trough. Row there is nothing 

 remarkable about this trough ; it is merely the re-excavation of the 

 Preglacial scarp-foot, and has been widened into a trough by the 

 recession of the chalk escarpment on the one side and the edge of 

 the Boulder-clay on the other side, this widening being due to the 

 agency of rain and springs, and having been in progress ever since 

 the formation of the Boulder-claj^. In that portion of the trough 

 which lies between the valleys of the Bain and Steeping there is a 

 floor of Middle Neocomian clay stretching continuously from side 

 to side ; but the Steeping valley is a hollow within the trough, and 

 is cut down through the Lower Neocomian sandstone, and into 

 the Kimmeridge Clay. 



Mr. Searles Wood "has noticed the limitation of the so-called 

 Hcssle Clay to the entrance of the Steeping valley, but does not offer 

 any explanation of this peculiar portion, merely remarking that if 

 the clay vrere an aqueous accumulation it should stretch up the 

 valley to the levels which it reaches elsewhere +. I am still of 

 opinion that the Hessle Clay is a marine accumulation, and offer 

 the simple explanation that at the time when the clay was formed, 

 the upper part of the valley in question had no existence. Accor- 

 ding to my view the formation of the Hessle Clay took place at an 

 early epoch in the history of the valley, and when its excavation 

 had not proceeded farther than the first stage described on p. 604, 

 its entrance as far as Partney being an open bay, into which the 

 Langton and Skendleby Becks emptied themselves. 



If Mr. Wood's views regarding the age and origin of the Steeping 



* Quart. Journ. Geol. Soc. vol. xxxiv. p. 457, and vol. xxxviii. p. 667 (1882). 

 t Quart. Journ. Geol. Soc. vol. xxxviii. p. 715. 



