Introduction Graptolites are most commonly found as flat-tened, often carbonized, material in black“grap-tolitic”shales, and most of the work done up un-til about ten years ago was on the description otsuch material. Material thus preserved commonlysuffers from three main drawbacks. Firstly, theflattening may distort the profile of the graptolite,and this distortion may vary with the position thatthe graptolite adopted when it fell on the sea floor,Secondly, relatively small features of the rhabdo-some, such as apertural spines and other processes