The data from a number of neutron and meson monitors are examined for the cosmic ray event of September 17--18, 1979. The profiles of the observed cosmic ray intensity increase at various stations exhibit an apparent solar flare origin, if one were to look at a limited amount of data. It is clearly shown that the 'flare-type' increase is unusual and is of nonsolar origin. A suggestion is made for explaining this in terms of interplanetary structures for which supportive evidence is provided by reference to in situ observations.