47 



On thr Xfi urturc ami Arrangement of the Tessera in a Roman 

 IHirrmritt iliscorrrr// at Cirencester in August 1849. By James 

 BuCKMAKj r.L.S., F.G.S. 



Read 22nd January 1850. 



Tin object of this paper is to point out the nature of the 

 materials of which the party-coloured floors so beautifully 

 wrought in ancient Roman dwellings are composed, as also to 

 offer some remarks upon their principles of arrangement. 



The tesserse of Roman pavements may be said to be formed 

 out erf two classes of materials, the first of which, consisting of 

 portions of various coloured rocks, may be termed natural ; the 

 second, of stained or coloured terra cottas and glass, being arti- 

 ficial. 



The natural tesserae furnish but few colours, and those of a 

 sober cast, hence these will be found forming shadings to figures 

 entering largely into the composition of borders, or filling up the 

 groundworks of the designs. They consist of portions of natural 

 rocks from various localities, those belonging to the district where 

 thr pavement is found, as far as I have observed, always contri- 

 buting their share. 



The Cirencester pavement presented the following : — 



Colours. Rocks. 



1. White, composed of Hard fine-grained Oolite. 



l\ Light yellow Pebbles of the Wiltshire Drift, and Oolite. 



3. Gray The same as No. 1, altered by heat. 



4. Slate colour or black ... Limestone bands of the Lower Lias. 



No. 1 occurs as a bed of compact fine-grained stone of about 

 :J feet thick in nearly all the freestone quarries of thi3 district, 

 where it is distinguished under the name of the Limestone bed ; 

 its geological position is about the middle of the freestone rocks 

 of the Great Oolite ; it is well exposed at Trewsbury quarry, at 

 the Acman Street Station, and at the smaller Sapperton tunnel, 

 and was no doubt obtained by the Romans from the quarries 

 once worked by them in the vicinity of the Querns. 



2. The tessera?, of a yellowish or nankeen hue, appear to 

 have been made of portion! of the pebble-drift with which parts 

 of the neighbourhood of Cirencester is so thickly strewn. Stray 

 pebblea of this may be found in almost every field to the south 

 of the town, whilst at Somerfbrd Kaynee, and other places, it en- 

 ters largely into the composition of the gravel beds which an 



