HABS has info on construction materials and says 45,000 dollars was the price.
http://cdn.loc.gov/master/pnp/habshaer/il/il0100/il0143/data...
It looks like quite a bit of this bridge is not original. I wonder if the original brick remains behind the concrete? The original ornamentation shown at the top of the towers in 1936 photos is missing in the 1971 photos, yet magically reappears in present day photos. Anchorages appear all-new. Cable saddles are modern.
It looks like the original estimate was around $9,000 and there were some shenanigans that led to the actual cost being estimated as five times the original estimate. The 1881 book describes this on page 85.
$40,000 in 1859 doesn't sound right. Maybe that's inflation adjusted to when the sign went up in 1976?
Great historic photos of the General Dean Bridge, nos. 8,9,10. Just a couple quick corrections to the captions, however. Photo #8 is described as "View From North-East"; actually it appears to have been taken from the south, looking north-northeast (the old river channel is seen curving eastward to the north of the bridge). #9 is described as a "View From South-West"; actually it's looking southwest from a vantage point to the northeast (old power plant on west river bank south of the bridge is easily seen). #10 is described as being of the "East End"; actually it's the west end looking northeast. I resided a number of years in Carlyle and lived 2 1/2 blocks west of the bridge on Fairfax Ave.
Would the brick ever have been visible? The report Don posted says they were plastered with cement mortar. That's from 1936.
I wonder why the bridge cost 5 times what it was supposed to.