Sorry Forfarian I need more help in understanding what I'm looking at...
As the only thing I can see is the extract posted on this thread, I don't know what you can see.
However if I look at the strings of numbers you have posted, this is what I think
GROS indicates General Register Office for Scotland, obviously.
291 is the number indicating the parish of Guthrie
We then have Volume 1 page 156 and Volume 1 page 157
Then finally Volume 2 page 5.
The extract posted reads
1819 April 12 Robert was born
The twelve preceding Entries are Extracted from the Register in the custody of the Registrar in terms of the Acts 17 & 18 Vict Cap 80 and 23 & 24 Vict Cap 85. One word and six figures deleted before signature. W P Dundas, Registrar General. It sounds as if Vol 1 Page 157 precedes Vol 1 Page 156. I have no idea why this would be, but I have tried to think up a procedure that might account for it. It makes no difference to the content of the registers.
If I find myself in the Angus Archives or Forfar Public Library with time on my hands and if I remember about it I might indulge my curiosity by taking a look at the microfilm(s) of the Guthrie parish registers to see if they shed any light on the page order. However I doubt that it would actually help to move Scott's brick wall, which I fear is more in the nature of a well-engineered solid stone dyke and not about to be easily, if at all, broken down.
