In a late nineteenth century account of the geology of this area it was mentioned that it was a common practise in Suffolk to cover manure heaps with the sand from the Crag as it acted as an absorbant; but, a more profitable use was referred to. The shelly Crag contained a high percentage of phosphate, as well as carbonate of lime from the shells and this was used on the soil as a fertiliser. The earliest notice of the employment of Crag as a fertiliser was recorded in a geological paper on the county.
At Woodbridge in Suffolk,... there are some Pits... consisting of several Strata of Shells from the Bottom to within about nine Feet from the Surface, where the natural Soil of Gravel and Sand begins... The Farmer, in whose Ground these Shells are, has, as I am informed, laid the Foundation of an ample Fortune from them. The Man contented himself in the old beateb Track of the Farmers,... till a happy Accident forced him on a bold Improvement. He used to mend his Cartways... with these Shells; in which Business his Cast one Day broke down, and threw the Shells out of the Cart Track into the cultivated Part of the Field. This spot produced so remarkable a Crop next Year, that he put some Loads upon a particular Piece, kept the Secret to himself, and waited the Event. This Trial answering Expectation, he directly took a Lease of a large Quantity of poor Land, a about five Shillings the Acre; and having manur‘d it heartily with these Shells, in about three Years it turned to so good an Account, that he had 15 Shillings an Acre proffer‘d to take the Lease out of his Hands.”
(Rev.R.Pickering,Phil.Trans.vol.xliii,1745, no.474, pp19 1-2; in W.Whitaker, ”Geology of Ipswich Etc.”1885, pp101-2.)
Whilst there has been no actual documentation for workings in the parish the 1873 trade directory pointed out that,
Since 1845, considerable excavations have been made in the neighbourhood for ”coprolites”, so called. These phosphorated nodules are found in the crag. They are chemically prepared and are extensively used for agricultural purposes. The diggings have brought to light numerous fossils, which appear to have been washed from the London clay and other strata, as they present, like the nodules, a water-worn appearance.” (Kelly‘s 1873)
There is the possibility that Edward Packard, one of the leading manure manufacturers during those days and who lived in Woodbridge, may have had arrangements made with farmers or landowners where the coprolites were found in the numerous crag pits that dotted the valley sides and had the fossils sent to his Ipswich works. Unfortunately no records exist of such undertakings.