In general, the 'insulae' on the east and west sides of the town were larger than those in the centre.
In this system perhaps the most peculiar feature is the intermixture of square and oblong 'insulae'.
The larger 'insulae', which lie west of the main north and south street, are oblong and measure about 150 x 100 yds.
A word should be added regarding the modern division of Pompeii into Regions, or wards, and insulae.
If the Graeco-Macedonian fashion be quoted as precedent for square or squarish 'insulae', the Terremare show the same.
But it is not easy to fix its area, nor are unmistakable 'insulae' to be detected outside them.
But, as there were nine 'insulae' from east to west, the main north and south street could not bisect the town.
The plan has been thought to imply 'insulae' twice as large as those of Timgad.
Modern plans seem sometimes to imply that the 'insulae' which abutted on the walls were also abnormally large.
The 'insulae', whatever their shape—square or oblong—are fairly uniform throughout.
insula in·su·la (ĭn'sə-lə, ĭns'yə-)
n. pl. -lae (-lē')
A circumscribed body or patch on the skin.
See island of Reil.