There have been many ideas and theories given for the demise of
the dinosaurs some 65,000,000 years ago.  Many have felt that the well known strike of a monster meteorite forming the Chicxulub crater discovered near the Yucatan Peninsula and measuring some 111 miles in diameter was the primary motivating force in the dinos becoming history. 

There have also been suggestions that perhaps other element in the ecology like viruses or other bacteria could have either helped
or sped up  the extinction process.  When scientists found an
unusual band of iridium on the earth twenty-six years ago it had others looking for the causal connection between the formation
of the Chicxulub crater and deposition of the iridium (rare on earth but not so rare in meteorites) and the chronology of the end of the Cretaceous time frame. 

The latest science is still in debate, as to whether or not the meteorite caused the end of the dinosaurs.  More evidence has been found to show that perhaps this Chicxulub crater is the culprit and for Macleod from the University of Missouri-Columbia-this is it.

Princeton University's Gerta Keller believes that the crater was
formed some 300,000 years before the extinction of the dinosaur's.  Given the length of time (65,000,000 years) 300,000 years might very well be within the error of accuracy in technology.

Dogma might still hold that providence was the reason, and so the cartoon below.