The Whitestone diorite is a prekinematic intrusion located in the south-western portion of the Grenville province of the Canadian Shield. Hornblende and biotite from the diorite display undistrubed 40Ar/39Ar release spectra which define average ages of 980 m.y. and 945 m.y., respectively. These dates are interpreted to record times of cooling through temperatures required for retention of radiogenic argon following Grenville metamorphism of the pluton at approximately 1150 m.y. Ueno et al. (1975) reported that the diorite carries a natural remanent magnetization which loses directional coherence at 580¿-64¿C. They concluded that these temperatures may be close to the geologic temperatures at which the magnetization was actually acquired. If so, this magnetization was likely acquired at a time and a temperature closely represented by argon retention in hornblende. The virtual geomagnetic pole (VGP) defined by the Whitestone diorite magnetization overlaps, within analytical uncertainty, the location of other VGP's which define the southwestern portion of the 'Grenville polar path,' and therefore all may have been acquired at approximately the same time. 40Ar/39Ar hornblende dates previously reported by Dallmeyer (1978a) for some of the rocks whose VGP's define the northeastern portion of the Grenville polar path are younger and suggest later cooling through argon retention (and magnetic blocking) temperatures between 880 and 900 m.y. The suggested time span for the Grenville polar path is 980--1000 m.y. (southwest) to 880--900 m.y. (northeast) and indicates that Grenvillian poles can be considered to form a late Proterozoic part of the North American polar path. Separate Grenvillian and Interior Laurentian polar paths do not seem reasonable in view of the available geochronologic and geologic controls.