From the investigation of the deposits, a block and ash flow was identified as well as an ash cloud surge. The block and ash flow deposits contained a coarse grained volcanic breccia with lithic debris and crystals. This unit flowed through the valley of the Riviere Blanche, which lies southwest of Mont Pelee, and out to the Caribbean Sea. The ash cloud surge, which lies up to 100m above the block and ash flow, is comprised of a fine grained tuff and lapilli.