On the Excavations at Rotherley, Woodcuts, and Bokerly Dyke. 289 



great states, for their defence, because the great armies of our time 

 are encumbered with large supplies of food and ammunition, that 

 have to be drawn from the rear, and for which it is necessary to keep 

 open lines of communication with the base of their operations, and 

 the frontier fortresses of an invaded state serve for the defence of 

 that state, because it is impossible for an invading army to pass 

 between them without exposing its lines of communication. Sucb 

 fortresses also serve as fortified magazines for an invading army. 

 But in barbarous times, such impedimenta did not exist in con- 

 nection with invading forces ; their objects were for the most part 

 predatory, and their wants were few, they could penetrate between 

 the fortified places, and subsist by plunder in the country surrounding 

 them, and the defenders of the fortresses, if they kept on the 

 defensive, and remained shut up in them, would only have to look 

 on. Wherever, therefore, we find such isolated encampments on 

 the tops of hills, in prehistoric times, we may be sure that they were 

 simply places of refuge for some local tribe inhabiting their vicinity, 

 to which they resorted when attacked by a neighbouring tribe. 

 They imply a low state of civilization, before the inhabitants of any 

 large district had attained to such organization as was necessary for 

 combined defence. 



When the people advanced to a higher state of civilization, and 

 several tribes combined for the defence of a district, it was not by 

 detached forts, but by continuous entrenchments, that they accom- 

 plished that object. They threw up continuous lines of ditch and 

 bank, the latter probably surmounted by a stockade, running for 

 miles along the open country, from an inaccessible position on one 

 flank to some other natural defence on the other flank ; and although 

 it may be true — as has often been said in support of the opinion 

 that these long entrenchments could not be defensive works — that 

 they would be difficult, or impossible, to defend at all points, yet we 

 know as a fact that this was the system adopted, and that the 

 Romans used it, not only in the north of Britain, as a defence 

 against the Picts and Scots, but also in the more extended defence 

 of their German frontier, by means of the Pfahlgraben, joining 

 the Rhine and Danube. When these continuous barriers were 



