Go read it all, but I'll draw attention to particular points of interest here.
The other side of the foldout has a map of Oxfordshire, which merely shows the outlines of the different regions within it. This map has a grid on it, and tellingly, parts of Oxfordshire are packaged up into different boxes that do not correspond to the grid. I suppose they could represent possible administrative areas within Pullman's universe, but it doesn't seem that way. If playing the AI game has taught me anything, it is that you don't go and produce a map like that in an expensive book for no reason. There is a reason for it to be there, and I think the boxes may have something to do with it.
Perhaps as furbaby says, to tell us about old/new Oxfordshire?
I do think there is something going on with the map, and also with its publishers, Smith and Strange Ltd., who are based in Oxford.
But the majority of the excerpt talks about The Eagle Ironworks, The Oxford Canal, the Fell Press and The Oratory of St. Barnabas the Chymist. There's an awful lot of information and details packed into those two pages which could hide anything.
Update: I have done a spot of research on this, which has uncovered some interesting facts. There is also an Eagle Ironworks in our world, occupying the same spot, but interestingly, it's referred to by many people as 'Lucy's Ironworks'. It was founded by a W. Lucy in 1825; a different person and date than in the 'other' Oxford. Sharp-eyed readers will note that the alchemist referred to in the excerpt is also called Lucy, and his daemon was an eagle. On my search, I found a book called The Eagle Ironworks Oxford : the story of W. Lucy and Company Limited by P.W.S. Andrews, written in 1965. It's available in several Oxford libraries and I may go and have a look some time.
As for The Fell Press, this is known as the Oxford University Press in our world. In an interview, Pullman commented mischievously, "Dr Fell, the origin of the rhyme ‘I do not like thee Dr Fell, the reason why I cannot tell, but this I know and know full well, I do not like thee Dr Fell’, was one of the original directors of the Oxford University Press and it was named after him. But you may read it as you like. Everything has meaning!"
Update: Everything points to something happening in Palmyra or Smyrna in the past. I think that in the other universe, there was a lesser St. Barnabas who somehow changed events and got caught up with Dust, and also with Queen Zenobia (she seems rather more prominent in that universe than in ours). I'm now pretty sure that The Book of Dust will concern itself with these events. I'm not sure if there is any more to find out...