The magnetic anomaly patterns due to thin lateral deposits of ore can
be very similar to those due to deposits in extended magma root struct
ures which potentially may be more important from a geophysical point
of view. New forms of the solutions for the anomalous magnetic field d
ue to vertical cylinders and to thin disks art given; these are suitab
le for fast computation. For various values of the local magnetization
vector of the body, the measured anomaly patterns are obtained and fe
atures are identified which serve to differentiate the patterns due to
a thin disk from those due to a semi-infinite vertical cylinder.