The pyrolysis of kerogen, which occurs in retorting and in related extraction processes, such as thermal solution, breaks down the complex kerogen structures into singular molecules, a number of which have been identified. Among these are a limited number of nitrogen-containing compounds of the substituted-pyridine class. Many authors report that qualitative tests show the presence of memberd of other classes of nitrogen, but positive identification of individual members is lacking. The conclusion that comparatively little is known concerning the nature of the nitrogen compounds of shale oil is inescapable.