Limestone. Basalt and granite are igneous rocks which means they're formed through lava but limestone is sedimentary so forms as layers <span>of shell etc are </span>deposited, meaning it's most likely to find fossils in it.
The tool that would be most useful to him would be a seismometer. It is an<span> instrument that measure motion of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions. Hope this answers the question. Have a nice day. </span>
