Chap. IV. OF ANCIENT BUILDINGS. 223 



Measdhements by Dr. H. Johnson of the thickness ob 

 the vegetabi,e mould over the eoman ediss at 

 Wroxetek. 



Trenches dug in a field called " Old Works." 



ThIckDRSi 



of mould in 

 inches. 



1. At a depth of 36 inches undisturbed sand was 



reached .. .. .. .. .. 20 



2. At a depth of 33 inches concrete was reached 21 



3. „ „ 9 inches concrete was reached 9 



Trenches dug in a field called "Shop 

 "Leasows ;" this is the highest field within the 

 old walls, and slopes down from a sub-central 

 point on all sides at about an angle of 2°. 



Tbickness 



of mould in 



inches. 



4. Summit of field, trench 45 inches deep ., 40 



5. Close to summit of field, trench 36 inches deep 26 



6. „ „ trench 28 inches deep 28 



7. Near summit of field, trench 36 inches deep 24 



8. „ „ trench at one end 39 

 inches deep ; the mould here graduated into 

 tho underlying undisturbed sand, and its 

 thickness is somewhat arbitrary. At the 

 other end of the trench, a causeway was en- 

 countered at a depth of only 7 inches, and 

 the mould was here only 7 inches thick .. 24 



9. Trench close to the last, 28 inches in depth .. 15 



10 Lower part of same field, trench 30 inches deep 15 



11 „ „ tiench 31 inches deep 17 

 12. „ „ t'-ench 36 inches deep, 



at which depth undisturbed -sand was reached 23 



