Breakdown of Numbers

This catalogue of Scottish bridges comprises all those which can be identified on any one of three ancient maps: the Military Survey of Scotland ( surveyed 1747-55), Timothy Pont's manuscripts (circa 1600) and  Joan Blaeu's Atlas Novus Vol V (published 1654).   Numerical analysis is affected by the confidence in the data.   In this context it was not difficult to distinguish a bridge on Roy's map and to attribute it to a present location. Blaeu's atlas is very clear but orientation is often poor and the absence of detailed contour on rivers and coasts sometimes needs an intelligent guess based on the proximity of named settlements.   This compromise is required even more when scanning Pont's manuscripts. Pont requires a great deal of interpretation: no differentiating colours or textures are used, overwriting is frequent and the maps are messy and cluttered; orientation is impossible and frequently a judgment is required as to whether or not a bridge is actually being described, far less where it is or whether it exists today.  Perhaps it is not surprising that this account of the number of bridges on Pont’s maps does not match the numbers found by one or two other researchers. 

 Any bridge which is not on one of these three maps has not been included whether or not this might appear to be an eighteenth century (or earlier) omission.   By definition, of course, some very fine later eighteenth century bridges will be absent whilst many younger than this are included by virtue of an older predecessor at the same location. 

There are 525 bridges in the catalogue.  Included are 44 which could be located with confidence on the map, but at locations where there is no bridge today.   Further research has confirmed that 157 (30%) of the 525   are preserved: i.e. they remain structurally intact and substantially as they were in the 18th century.  They have been given a maroon coloured marker on the OS map.  The remaining 368 have been given a navy marker, indicating that they have been completely replaced by a more modern structure, or so extensively repaired and restructured that they no longer qualify as preserved; some no longer exist or remain only as a ruin. 

There are more bridges in the South than in the North ( 298/227).  However, there are fewer 'preserved' bridges in the South (70/87).  It is clear from the distribution that there was an enthusiastic 19th century programme of replacement in the central belt, which largely accounts for this. 

There are 30 bridges which firmly belong to the 16th century, both historically and architecturally  (interestingly, Harrison estimates a count of 200 in England). There is room for discussion about some dating features.  Most of these bridges are pre-reformation multi-arched bridges, but there are seven single arches which belong to the same period.  Bridges in this whole group are given a red marker.       A separate list is provided.      

Eight of the bridges which are structurally pre-1600 are still taking vehicle traffic, along with a further sixty of those which have pre-1750 structure.  Mostly, these bridges are on very minor roads. 

The breakdown from the three maps is as follows-

Roy 408 bridges      Pont  128 bridges      Blaeu   172 bridges  

As expected, there is considerable overlap. For example 137 can be found on more than one map and 44  are present on all three.  

There were 246  bridges on the older two maps which suggests a 16th century date.  Fifty-nine of these remain today and are in the preserved group. Many from this group are also on Roy's map, so the 'preserved' notation of a maroon marker may imply no more than an 18th century date for the structure.   However, thirty seven bridges from this group of fifty-nine were not thought to be architecturally from the 16th century and this may need to be reviewed in the light of their clear presence on these earlier maps.  More information can be seen here.       

Joan Blaeu acquired much of his Scottish data from Timothy Pont's original manuscripts. One might expect the two maps largely to correspond.   However, in this work, although there are 128 bridges on Pont's map and 172 on Blaeu, only 47 are present on both.  This seems to confirm an impression that Gordon’s commission (from Blaeu. see sources) was to expand the geographical limits of Pont’s mapping. We know that neither map was comprehensive in its geographical cover of Scotland, but it does seem that each offers a distinct, though overlapping coverage.  Sadly some regions are missed by both maps: in particular, southern parts of Perthshire and Angus and some of Stirlingshire and Clackmannan.  

There is one major surprise, which may pertain as much to mapping as to bridges.    Roy's map was commissioned specifically for the Hanovarian army.  Such was its strategic importance,  that it was not released into the public domain until 50 years after its completion. On military maps the importance of bridges is self-evident, yet there are 117 bridges from the older maps which cannot be found on Roy and yet 88 of these locations have a bridged crossing today.   Some may well have been ruins in 1750 or did not exist at that time. For examples, we know the the 14th Century bridge at Perth was 'down' while Roy was conducting his survey; Dumbarton had a bridge in 1600 ( Pont 32 and 33)  which disappeared and was not replaced until the 19th century; the 18th century main road to Bishop’s Bridge in Perthshire had been recently rerouted, by the army,  to bypass the bridge.   But 117  is a large number and amounts to 22% of the collection.  This may suggest that Roy's surveying was less rigorous than might be expected.  However, alternatively it might suggest that bridges are a less reliable feature than we think -  more ephemeral, becoming ruinous or temporarily non-existent from one century to the next.  This view might be supported by the existence of twenty-nine bridges located on the older maps that still have no bridged crossing today.  One final interpretation of this anomaly is supported by MacFarlane’s Geographical Collections which date around 1720.  Wooden bridges, as identified by Macfarlane, seem to be absent on Roy’s map (1750) - which suggests that Roy’s notation (a double red coloured bar) might only apply to masonry bridges.   Since many of Pont’s bridges may have been wooden, and may have still been so, in 1750, then this would explain their absence on the Roy map. 


Dec. 2012                                      Site last updated  Feb 2019