Doctor Who and the Cave Monsters — Malcolm Hulke

All is not well at the Wenley Moor underground atomic research station: there are unaccountable losses of power-output; nervous breakdowns amongst the staff; and then--a death! -- UNIT is called in and the Brigadier is soon joined by Doctor Who and Liz Shaw in a tense and exciting adventure with subterranean reptile men Silurians and a 40 ft. high Tyrannosaurus rex, the biggest, most savage mammal which ever trod the earth!