First picture posted shows the Goree Island twin 240mm battery in an open top turret. A four gun 198mm battery is just off the picture at the top left. The second picture is of the 240mm battery in four single mounts at Mamelles. The third picture posted is a ground level pix of Mamelles.
Other batteries located on Google surrounding Dakar include:
Goree Island 4 canon 198mm (above) and 4 canon 90mm (90mm emplacements not located on Google)
Cap Manuel west of Goree Island. Twin 240mm mounting like Goree Island
Bel Air North of Goree Island. Twin 240mm mounting like Goree island
Madeleines 3 canon of 138mm single emplacements between Mamelles and Cap Manuel
Rufisque 2 canon 95mm on East side of bay in a fenced in compound
Yoff 4 canon 155mm on the north side covering the northern beaches (emplacements not located)
Fann 4 canon 90mm on the west side between Mamelles and Madeleines (emplacements not located)
A photograph of the Goree Island turret is at
.
39-45 Magazine, Issue #234 Mai 2006, has a map of Dakar with battery locations and arcs of fire.