TRACES OF AN INTERGLACIAL LAND-SURFACE AT CREWE. 51 
than on the other) were produced by rain when the surfaces of 
the laminzw were above water; but in most instances they can be 
better explained by supposing the escape of imprisoned bubbles 
of air; and Mr. Smppatt believes that he has seen a confirmation 
of this theory of their origin in experimenting with the clay 
while dissolved in water contained in glass bottles. 
‘ Clay, very similar to that found under Crewe Railway Station, 
may now be seen in course of accumulation along the shores of 
some parts of the estuary of the Mersey, and more especially in 
the back-waters of the Menai Strait; and Mr. Simpatr is of 
opinion that the Crewe leaf-clay was deposited within the tidal 
range ; but while believing that it may have been partly formed 
between high and low water, I have seen very similar clayey 
lamine with intercalated sprinklings of sand, and pits left by 
air-bubbles (besides rain-pits) at some distance from the sea. 
Around Birkenhead (and I have no doubt elsewhere), at the 
bottom of excavations made for obtaining clay for making bricks, 
rainwater, assisted by wind, has produced a laminated clay very 
similar, in the respects already named, to that found under Crewe 
Railway Station, with the addition of marks (in the Birkenhead 
excavations certainly, and at Crewe probably), left by the 
erawling of worms. 
During his microscopic examinations of the Crewe leaf-clay, 
Mr. Srppatt found the débris of plants, including rootlets, one 
of which certainly was in the position in which it grew, as it 
extended through the clayey lamine in a direction of nearly 
right angles to the planes of lamination; in other words, it 
occupied a position in which a drifted specimen could not well 
have remained had the lamine been accumulated around it by 
currents of water. 
From all the above facts and considerations, I think it may be 
regarded as highly probable, if not certain, that in Cheshire, the 
land before the commencement of the submergence which 
accompanied the deposition of the upper Boulder-clay, with its 
intensely striated stones, stood at a level not much lower than it 
does at the present day. 
