Darkness at the Crucifixion

The following passage, in a volume of Lectures by the Rev. H. Blunt, has fallen under my notice:— "It was this Dionysius (the Areopagite) of whom the earliest Christian historians relate that, being at Heliopolis, in Egypt, at the time of our Lord's crucifixion, when he beheld the mid-day darkness which attended that awful event, he exclaimed, 'Either the God of Nature suffers, or the frame of the world will be dissolved.'" Having very limited opportunity of studying the ancient historians, I should be greatly obliged if you would inform me from what work this account is derived; or refer me t…