unless he knew they were there."

"What do you mean exactly, Sowerby?" said Dunbar, taking out his
fountain-pen and tapping his teeth with it.

"I mean," said Sowerby, "that someone connected with the gang must have
located the site of these vaults from some very old map or book."

"I think you said that the Reverend Somebody-or-Other avers that they
were a crypt?"

"He does; and when he pointed out to me the way the pillars were placed,
as if to support the nave of a church, I felt disposed to agree with
him. The place where the golden dragon used to stand (it isn't really
gold, by the way!) would be under the central aisle, as it were; then
there's a kind of side aisle on the right and left and a large space at
top and bottom. The pillars are stone and of very early Norman pattern,
and the last three or four steps leading down to the place appear to
belong to the original structure. I tell you it's the crypt of some old
forgotten Norman church or monastery chapel."

"Most extraordinary!" muttered Dunbar.

"But I suppose it is possible enough. Probably the church was burnt or
destroyed in some other way; deposits of river mud would gradually
cover up the remaining ruins; then in later times, when the banks of
the Thames were properly attended to, the site of the place would be
entirely forgotten, of course. Most extraordinary!"

"That's the reverend gentleman's view, at any rate," said Sowerby, "and
he's written three books on the subject of early Norman churches! He
even goes so far as to say that he has heard--as a sort of legend--of
the existence of a very large Carmelite monastery, accommodating over
two hundred brothers, which stood somewhere adjoining the Thames within
the area now covered by Limehouse Causeway and Pennyfields. There is a
little turning not far from the wharf, known locally--it does not appear
upon any map--as Prickler's Lane; and my friend, the vicar, tells me
that he has held the theory for a long time"--Sowerby referred to
his notebook with great solemnity--"that this is a corruption of
Pre-aux-Clerce Lane."

"H'm!" said Dunbar; "very ingenious, at any rate. Anything else?"

"Nothing much," said Sowerby, scanning his notes, "that you don't know
already. There was some very good stuff in the place--Oriental ware and
so on, a library of books which I'm told is unique, and a tremendous
stock of opium and hashish. It's a perfect maze of doors and
observation-traps. There's a small kitch