Ian Cundell wrote in message ...
In article ,
(Leo) wrote:

Ian Cundell wrote in message
...
In article ,
(Leo) wrote:

Part of my garden in St Albans has not much topsoil.
The subsoil is a heavy clay with plenty of flints.
After a lot of digging in organic matter and picking
out rocks I have a pretty good vegetable bed. I've
noticed that at least one area has a lot of lumps of
chalk as well.

Does anyone have an idea whether these are a feature
of the local soil, or perhaps plaster debris from the
building of the house (30s) or something else?

Leo

Well the bedrock to St Albans is chalk (if you drive along Batchwood
Drive you are driving down a classic chalkland dry valley). Basically
the area is chalk lee slope (the scarp slop faces north at Dunstable)
topped by post-glacial outwash (hence the flints). If you want to see
the same without the clay topping go up to Dunstable Downs.

I suppose it is possible that the construction of the house got down to
the bed, but it doesn't feel very likely.

Thanks for that. My house is on quite a steep slope (it's a semi but our
half is more than a metre higer than the neighbor),

Seymour Road or Marshalls Ave, per chance?

no, Hordle Gardens

so producing level-ish
gardens would have involved quite a bit of earth moving, which probably
explains it. Is there a good book or website with local geological
information?

Aha. That might explain it.

Bizarrely Amazon throws up "Quaternary geology of the Vale of St.
Albans: Field excursion guide, July, 1978" ISBN B0000EH909.

But alas it is not in stock - I guess someone must have sold a used one
in the marketplace at some point.

Try either of the museums (Hatfield Road probably the best bet) and the
library (it has a decent local studies section and the staff are pretty
helpful). Might be worth asking in Ottakar's.

and Google gave this

http://www.hertsgeolsoc.ology.org.uk...rtsGeology.htm

Thanks for those pointers, you googled more cleverly than I

Leo