An instrument is described that will take high resolution photographs of silt‐clay bottom types in profile. The bottom (10–20 cm) is penetrated by a slowly descending (⩽7 cm/sec) wedge‐shaped Plexiglas chamber, and the sediment profile that is cut is photographed. Such photographs reveal in situ details of bottom topography, sediment texture, depth of bioturbation, biogenic structures, and living positions of mud‐dwelling benthos.The instrument can be modified to take closeup vertical photographs of the bottom and to obtain undisturbed core samples.