about　three　centuries；　and　no　doubt　much　matter　must　have
  accumulated　within　the　walls　during　this　long　period。　　It　appears
  to　have　been　destroyed　by　fire；　and　most　of　the　stones　used　in　the
  buildings　have　since　been　carried　away。　　These　circumstances　are
  unfavourable　for　ascertaining　the　part　which　worms　have　played　in
  the　burial　of　the　ruins；　but　as　careful　sections　of　the　rubbish
  overlying　an　ancient　town　have　seldom　or　never　before　been　made　in
  England；　I　will　give　copies　of　the　most　characteristic　portions　of
  some　of　those　made　by　Mr。　Joyce。　　They　are　of　too　great　length　to
  be　here　introduced　entire。
  An　east　and　west　section；　30　ft。　in　length；　was　made　across　a　room
  in　the　Basilica；　now　called　the　Hall　of　the　Merchants　（Fig。　9）。
  The　hard　concrete　floor；　still　covered　here　and　there　with
  tesserae；　was　found　at　3　ft。　beneath　the　surface　of　the　field；
  which　was　here　level。　　On　the　floor　there　were　two　large　piles　of
  charred　wood；　one　alone　of　which　is　shown　in　the　part　of　the
  section　here　given。　　This　pile　was　covered　by　a　thin　white　layer　of
  decayed　stucco　or　plaster；　above　which　was　a　mass；　presenting　a
  singularly　disturbed　appearance；　of　broken　tiles；　mortar；　rubbish
  and　fine　gravel；　together　27　inches　in　thickness。　　Mr。　Joyce
  believes　that　the　gravel　was　used　in　making　the　mortar　or　concrete；
  which　has　since　decayed；　some　of　the　lime　probably　having　been
  dissolved。　　The　disturbed　state　of　the　rubbish　may　have　been　due　to
  its　having　been　searched　for　building　stones。　　This　bed　was　capped
  by　fine　vegetable　mould；　9　inches　in　thickness。　　From　these　facts
  we　may　conclude　that　the　Hall　was　burnt　down；　and　that　much　rubbish
  fell　on　the　floor；　through　and　from　which　the　worms　slowly　brought
  up　the　mould；　now　forming　the　surface　of　the　level　field。
  A　section　across　the　middle　of　another　hall　in　the　Basilica；　32
  feet　6　inches　in　length；　called　the　AErarium；　is　shown　in　Fig。　10。
  It　appears　that　we　have　here　evidence　of　two　fires；　separated　by　an
  interval　of　time；　during　which　the　6　inches　of　〃mortar　and　concrete
  with　broken　tiles〃　was　accumulated。　　Beneath　one　of　the　layers　of
  charred　wood；　a　valuable　relic；　a　bronze　eagle；　was　found；　and　this
  shows　that　the　soldiers　must　have　deserted　the　place　in　a　panic。
  Owing　to　the　death　of　Mr。　Joyce；　I　have　not　been　able　to　ascertain
  beneath　which　of　the　two　layers　the　eagle　was　found。　　The　bed　of
  rubble　overlying　the　undisturbed　gravel　originally　formed；　as　I
  suppose；　the　floor；　for　it　stands　on　a　level　with　that　of　a
  corridor；　outside　the　walls　of　the　Hall；　but　the　corridor　is　not
  shown　in　the　section　as　here　given。　　The　vegetable　mould　was　16
  inches　thick　in　the　thickest　part；　and　the　depth　from　the　surface
  of　the　field；　clothed　with　herbage；　to　the　undisturbed　gravel；　was
  40　inches。
  The　section　shown　in　Fig。　11　represents　an　excavation　made　in　the
  middle　of　the　town；　and　is　here　introduced　because　the　bed　of　〃rich
  mould〃　attained；　according　to　Mr。　Joyce；　the　unusual　thickness　of
  20　inches。　　Gravel　lay　at　the　depth　of　48　inches　from　the　surface；
  but　it　was　not　ascertained　whether　this　was　in　its　natural　state；
  or　had　been　brought　here　and　had　been　rammed　down；　as　occurs　in
  some　other　places。
  The　section　shown　in　Fig。　12　was　taken　in　the　centre　of　the
  Basilica；　and　though　it　was　5　feet　in　depth；　the　natural　sub…soil
  was　not　reached。　　The　bed　marked　〃concrete〃　was　probably　at　one
  time　a　floor；　and　the　beds　beneath　seem　to　be　the　remnants　of　more
  ancient　buildings。　　The　vegetable　mould　was　here　only　9　inches
  thick。　　In　some　other　sections；　not　copied；　we　likewise　have
  evidence　of　buildings　having　been　erected　over　the　ruins　of　older
  ones。　　In　one　case　there　was　a　layer　of　yellow　clay　of　very　unequal
  thickness　between　two　beds　of　debris；　the　lower　one　of　which　rested
  on　a　floor　with　tesserae。　　The　ancient　broken　walls　appear　to　have
  been　sometimes　roughly　cut　down　to　a　uniform　level；　so　as　to　serve
  as　the　foundations　for　a　temporary　building；　and　Mr。　Joyce　suspects
  that　some　of　these　buildings　were　wattled　sheds；　plastered　with
  clay；　which　would　account　for　the　above…mentioned　layer　of　clay。
  Turning　now　to　the　points　which　more　immediately　concern　us。　　Worm…
  castings　were　observed　on　the　floors　of　several　of　the　rooms；　in
  one　of　which　the　tesselation　was　unusually　perfect。　　The　tesserae
  here　consisted　of　little　cubes　of　hard　sandstone　of　about　1　inch；
  several　of　which　were　loose　or　projected　slightly　above　the　general
  level。　　One　or　occasionally　two　open　worm…burrows　were　found
  beneath　all　the　loose　tesserae。　　Worms　have　also　penetrated　the　old
  walls　of　these　ruins。　　A　wall；　which　had　just　been　exposed　to　view
  during　the　excavations　then　in　progress；　was　examined；　it　was　built
  of　large　flints；　and　was　18　inches　in　thickness。　　It　appeared
  sound；　but　when　the　soil　was　removed　from　beneath；　the　mortar　in
  the　lower　part　was　found　to　be　so　much　decayed　that　the　flints　fell
  apart　from　their　own　weight。　　Here；　in　the　middle　of　the　wall；　at　a
  depth　of　29　inches　beneath　the　old　floor　and　of　49。5　inches　beneath
  the　surface　of　the　field；　a　living　worm　was　found；　and　the　mortar
  was　penetrated　by　several　burrows。
  A　second　wall　was　exposed　to　view　for　the　first　time；　and　an　open
  burrow　was　seen　on　its　broken　summit。　　By　separating　the　flints
  this　burrow　was　traced　far　down　in　the　interior　of　the　wall；　but　as
  some　of　the　flints　cohered　firmly；　the　whole　mass　was　disturbed　in
  pulling　down　the　wall；　and　the　burrow　could　not　be　traced　to　the
  bottom。　　The　foundations　of　a　third　wall；　which　appeared　quite
  sound；　lay　at　a　depth　of　4　feet　beneath　one　of　the　floors；　and　of
  course　at　a　considerably　greater　depth　beneath　the　level　of　the
  ground。　　A　large　flint　was　wrenched　out　of　the　wall　at　about　a　foot
  from　the　base；　and　this　required　much　force；　as　the　mortar　was
  sound；　but　behind　the　flint　in　the　middle　of　the　wall；　the　mortar
  was　friable；　and　here　there　were　worm…burrows。　　Mr。　Joyce　and　my
  sons　were　surprised　at　the　blackness　of　the　mortar　in　this　and　in
  several　other　cases；　and　at　the　presence　of　mould　in　the　interior
  of　the　walls。　　Some　may　have　been　placed　there　by　the　old　builders
  instead　of　mortar；　but　we　should　remember　that　worms　line　their
  burrows　with　black　humus。　　Moreover　open　spaces　would　almost
  certainly　have　been　occasionally　left　between　the　large　irregular
  flints；　and　these　spaces；　we　may　feel　sure；　would　be　filled　up　by
  the　worms　with　their　castings；　as　soon　as　they　were　able　to
  penetrate　the　wall。　　Rain…water；　oozing　down　the　burrows　would　also
  carry　fine　dark…coloured　particles　into　every　crevice。　　Mr。　Joyce
  was　at　first　very　sceptical　about　the　amount　of　work　which　I
  attributed　to　worms；　but　he　ends　his　notes　with　reference　to　the
  last…mentioned　wall　by　saying；　〃This　case　caused　me　more　surprise
  and　brought　more　conviction　to　me　than　any　other。　　I　should　have
  said；　and　did　say；　that　it　was　quite　impossible　such　a　wall　could
  have　been　penetrated　by　earth…worms。〃
  In　almost　all　the　rooms　the　pavement　has　sunk　considerably；
  especially　towards　the　middle；　and　this　is　shown　in　the　three
  following　sections。　　The　measurements　were　made　by　stretching　a
  string　tightly　and　horizontally　over　the　floor。　　The　section；　Fig。
  13；　was　taken　from　north　to　south　across　a　room；　18　feet　4　inches
  in　length；　with　a　nearly　perfect　pavement；　next　to　the　〃Red　Wooden
  Hut。〃　　In　the　northern　half；　the　subsidence　amounted　to　5。75　inches
  beneath　the　level　of　the　floor　as　it　now　stands　close　to　the　walls；
  and　it　was　greater　in　the　northern　than　in　the　southern　half；　but；
  according　to　Mr。　Joyce；　the　entire　pavement　has　obviously　subsided。
  In　several　places；　the　tesserae　appeared　as　if　drawn　a　little　away
  from　the　walls；　whilst　in　other　places　they　were　still　in　close
  contact　with　them。
  In　Fig。　14；　we　see　a　section　across　the　paved　floor　of　the　southern
  corridor　or　ambulatory　of　a　quadrangle；　in　an　excavation　made　near
  〃The　Spring。〃　　The　floor　is　7　feet　9　inches　wide；　and　the　broken…
  down　walls　now　project　only　0。75　of　an　inch　above　its　level。　　The
  field；　which　was　in　pasture；　here　sloped　from　north　to　south；　at　an
  angle　of　30　degrees；　40　seconds。　　The　nature　of　the　ground　at　some
  little　distance　on　each　side　of　the　corridor　is　shown　in　the
  section。　　It　consisted　of　earth　full　of　stones　and　other　debris；
  capped　with　dark　vegetable　mould　which　was　thicker　on　the　lower　or
  southern　than　on　the　northern　side。　　The　pavement　was　nearly　level
  along　lines　parallel　to　the　side…walls；　but　had　sunk　in　the　middle
  as　much　as　7。75　inches。
  A　small　room　at　no　great　distance　from　that　represented　in　Fig。　13；
  had　been　enlarged　by　the　Roman　occupier　on　the　southern　side；　by　an
  addition　of　5　feet　4　inches　in　breadth。　　For　this　purpose　the
  southern　wall　of　the　house　had　been　pulled　down；　but　the
  foundations　of　the　old　wall　had　been　left　buried　at　a　little　depth
  beneath　the　pavement　of　the　enlarged　room。　　Mr。　Joyce　believes　that
  this　buried　wall　must　have　been　built　before　the　reign　of　Claudius
  II。；　who　died　270　A。D。　　We　see　in　the　accompanying　section；　Fig。
  15；　that　the