Cathedral of Our Lady of Fair Haven of Roseau, originally known in French as Église de Notre-Dame du Bon Port du Mouillage de Roseau - Exterior and interior. Materials are volcanic stone. Well written article on wiki. See the link: http://en.wikipedia.org/wiki/Roseau_Cathedral.
This Cathedral is listed as a UNESCO World Heritage Site.
The photos below shows the rear and interior of the Cathedral. Again wiki has done a great job.