In height) stretching from Moulins-la-Marche on the north-west to Montmirail on the south; within the basin formed thereby the shape of which is defined by the Huisne, an affluent of the Sarthe, lie the chief towns - Mortagne, Nogent-le-Rotrou and Belleme.
He continued to serve as a representative during the short remainder of the republic. At the coup d'etat of the 2nd December 1851 he was arrested along with the other members of the opposition; but after a short imprisonment at Ham he was released, and, with his newly-married wife, lived in retirement till his death, which took place at Ourne (Sarthe) on the 28th of October 1857.
In the next year he was elected deputy for the arrondissement of Saint-Calais (Sarthe) in the republican interest.
In 1899 Cavaignac was an unsuccessful candidate for the presidency of the republic. He had announced his intention of retiring from political life when he died at his country-seat near Flee (Sarthe) on the 25th of September 1905.
In the Rennes basin limestones - often dolomitic - are associated with quartzites and conglomerates; silicious limestones also occur in the Sarthe region.