lit . 'THE HISTORY Book L gravel at preient, along the whole track of the road, are placed rterely in the attending channel of the river. And from the fame refounces muft the Romans have furnilhed themfelves with
- the gravel of their road within the pariih. From thofe unex*
haufted and inexhauftible ihoals of gravel in the Mediock and m the Irwell which were immediately at the ford of Knot- mill, -and are now immediately below the bridge of Salfbrd, at Boltoa* weel near Strangeways, and at Scarweel above Broughton-Ford, were the materials undoubtedly colle&ed. Thus conftru&ed with water-gravel appears to have been the broad item of the two -roads to Kinderten and to Slack in Cattle-field, as the fragments of rock which have been occasionally difcovered in the gravel fuflftcieatiy demofiftrate. And this conftru&ion of Roman roads with water-gravel refutes at once the wild prejudices that at prefent prevail againft it ; as the compa&nefs of the gravel un- der Mr. Philips^ houfe, and the firmnefs of the road in Caftle- field, demonftrates it to be equally binding with the land-gravel. But, to give it this binding quality, fbmething more is required than the prefent cenftru&ers of our northern roads take the trouble to praftife. To give^ it this quality, the gravel ihouM
- not be ufed in die naked ftate in which it is left by the river,
deprived of its fand and loam by the filtering waters, and thereby Tendered incapable of binding. Being laid upon the road in this condition, the ftones and pebbles are violently ground againft each other by the ftiong preffure upon the whole, and are foon powdered into dirt. But the Romans foggeft to us a very dif- ferent procedure, and advHe prudence to add what the water has wafhed away. This we fee exemplified in the road upon Stony-Knolls. And this was difcovered to have been pra&ifed in the road along Caftle-field and in the way under Mr. Philips's houfe. Thus conftru&ed, muft the caufeway have extended to the icager current of the Ribble and to the elegant lite of Ribchefter beyond it. This village the numerous remains of ruined mag- nificence, and the great multiplicity of Roman urns Roman coins end Roman monuments, have long demonftrated to have been 6 a con-
