• Home page
 • Resumé
 • Publications

Distribution maps
 • Granite-tempered ware
 • Cam. 262 / le type Besançon

 • All sites
 • Concordance with Ferdière 1972
 • Source of illustrations

 • TF1 - Granite-tempered
 • [Sample thin section]
 • [Hi-res (DjVu) image]
 • TF2 - `Standard fabric`

Camulodunum type 262, le type Besançon and Central Gaulish granite-tempered ware

Petrological description of granite-tempered ware (TF1)

TF1 fabric is characterized in the hand specimen by abundant biotite visible on the sherd surfaces. On broken edges it can be seen that the ware also contains abundant rock fragments, some up to 5mm across. On examination under a binocular microscope it becomes clear that these rock fragments are not crushed rock, since their edges are not fresh, even though angular edges exist.

In thin-section the rock fragments are shown to be derived from a granite. Large, composite fragments exist to demonstrate that the various minerals present were once part of the same rock, although in most cases this rock has decomposed into its constituents.

The most common minerals are felspars. Within this group fragments with a perthitic texture are very common. Orthoclase felspar is also present together with a little plagioclase felspar. Some of the perthitic and orthoclase felspar fragments are up to 5mm across, while the plagioclase felspar rarely occurs in fragments larger than 0.5mm across.

Biotite is the next most common mineral and is abundant as sheaves of crystals up to 1.0mm long and 0.5mm wide.

Quartz is present in smaller quantities, being moderate in abundance. Few fragments are larger than 0.5mm across. Some of the quartz contains fine cracks stained by amorphous brown material and the scarcity of crystal boundaries shows that the quartz originally occurred as large crystals.

A few thin-sections revealed inclusions with a different origin. Rounded fragments of ferruginous sandstone between 2mm and 4mm across were present in two sections. The sandstone contained subangular quartz fragments up to 0.3mm across in an opaque to dark brown matrix. One thin-section contained a single rounded fragment of lava, 1mm across (B247) while another section contained rounded white clay pellets up to 0.5mm across formed, perhaps, by the total weathering of orthoclase felspar.

These inclusions are set in a groundmass which consists of anisotropic clay minerals and angular fragments of biotite and quartz. Felspars may also be present as small fragments but are difficult to identify. The characteristics of this fabric suggest that the parent clay formed through the weathering in situ of a coarse-grained granite, although the sparse non-granitic rock fragments suggest that a small amount of material may have entered the clay from other sources, such as overlying sands or even through accidental contamination by man.

Alan Vince
9th February 1990

Photographs of thin sections are available here.

Summary of thin-sections

Show more details of these samples
TS ID Site name form
20 Alet
21 Alet
22 Alet
23 Alet
24 Alet Cam 262
26 Alet Cam 262
115 Amboise Sherd (Class 1 or Cam 262)
116 Amboise Sherd (Class 1 or Cam 262)
119 Amboise Cam 262
124 Amboise Cam 262
125 Amboise Cam 262/Class 2
129 Amboise Class 2
247 Basel Class 1
215 Chartres Cam 262
3 Colchester Cam 262
4 Colchester Cam 45A
100 Dambron Cam 262
101 Dambron Cam 262
269 Mont Avrollot Cam 262
176 Mont Beuvray Cam 262
270 Mont Beuvray Cam 262
31 Orleans Cam 262
35 Orleans Sherd
47 Orleans Cam 262
138 Orleans Class 2
142 Orleans Sherd
144 Orleans Class 1
154 Orleans Cam 262
181 Roanne Class 1/2
182 Roanne Class 1/2
183 Roanne Class 1/2
167 Saint-Marcel Dolia
169 Saint-Marcel Sherd
170 Saint-Marcel Sherd
1 Silchester Cam 262
224 Tours Cam 262
 • Url: • Author: • Last updated: 29 July, 2004 •