SOME ANCIENT BEITISH REMAINS. 99 



the Romans invaded Britain. The latter people, of course, 

 made immense improvements, but in numberless cases 

 adopted the line of ancient trackways, remaking them on a 

 better and more durable plan. The Fosse Way was almost 

 certainly one of these ancient British tracks. After pass- 

 ing Exeter in the south-westerly course, it went on by 

 Chudleigh, and across the middle of Dartmoor. Here 

 its remains are now known as the " Great Central Track- 

 way " ; and hero also it was little, if at all, modified by the 

 Romans. Its width is about 10 feet, and its vertical depth 

 2 to 2^ feet. Rough stones have been rudely built together 

 so as to form a raised causeway ; and the minor irregulari- 

 ties of the surface were filled in with granite gravel, which 

 abounds all over the moor. Compared with a typical 

 Roman road built in several layers of different material, its 

 structure is very simple ; but it must nevertheless have 

 well served its purpose. 



(12) Stone Avenues, or Parallelithoxs, are, on Dart- 

 moor, double, sometimes treble, rows of moderate-sized stones 

 projecting 2 to 3 1 feet above ground, and 3 or 4 feet apart, 

 extending in nearly straight lines for variable distances, 

 from a few feet to several hundred yards. There are remains 

 of stone avenues, composed of much larger stones, on Salis- 

 bury Plain, and at Stanton Drew and other places in Great 

 Britain ; while abroad, the best known examples of some- 

 what similar antiquities are the huge stone lines at Karnac 

 in Brittany. 



(13) Barrows and Cairns are often included under the 

 general term " Tumuli." The first term is applicable to 

 those mounds which consist chiefly of earth ; while the 

 second implies that the heap is composed entirely of stones. 

 They are often of large size, 30 yards or more in diameter, 

 but are usually smaller ; sometimes so weathered and reduced 



