176 
Evidence of Subsidence at Hull. 
fusain are sufficiently definite and uniform to be described as 
true constituents of humic coal, but that clarain and durain 
are not definite uniform constituents ; they are aggregations 
of different materials and are therefore types of coal aggregates 
rather than constituents. 
EVIDENCE OF SUBSIDENCE AT HULL. 
I have had an enquiry as to whether there is any evidence of 
the area round the City of Hull having subsided in com- 
paratively recent times. The peat beds under Hull indicate 
that there have been changes in level in early times, but it 
occurred to me that possibly the weight of the enormous 
number of houses and other buildings to meet the demands 
of a population of nearly 350,000 may have caused some slight 
depression. It will be borne in mind that the area upon 
which Hull is built is old Humber silt, and beneath it the 
spongy peat beds still cause plates to rattle and windows to 
shake when heavy traffic pass along the roads. It occurred 
to me that Mr. A. Tulip, Chief Engineer for Docks at Hull, 
might have some information on the point, and I therefore 
wrote him on the matter. He gives the following informa- 
tion which I think should be recorded : ‘ There is no direct 
data in this office with regard to local subsidence due to the 
causes you mention, but there appears to be evidence that in 
certain localities of the British Isles, other than colliery 
districts, surface movement has occurred since the ordnance 
survey in 1888. This fact specially came to my notice in 
1929 when using the revised ordnance surveys which were 
published about 1926, whereon the levels are reduced to the 
Newlyn datum instead of the Liverpool datum adopted in the 
previous surveys. Certain discrepancies were apparent after 
the various levels were adjusted to the new datum, and I 
wrote to the Director General of the Ordnance Survey Office 
with regard to these. I was specially concerned at this time 
with the Hedon Road (East Hull) district, and from informa- 
tion supplied there appears to have been a subsidence of the 
building on which the bench mark was cut of 0.186 feet 
between 1888 and 1908, and a further settlement between 
1908 and 1926 of about 0.1 feet. Similar figures occur at 
other bench marks. This sinking, however, is not necessarily 
consequent upon the vibratory effect of heavy traffic, as same 
of the bench marks are not in the close vicinity of high roads 
carrying heavy traffic. ’ The shrinking of the clay subsoil 
due to drainage may be a factor. — T.S. 
The Naturalist 
