It is a common question and the answers are easily understood when we take God at His Word and believe the record He has left us in the Bible. First I would like to state unequivocally, marine dinosaurs were created on the 5th day of the creation week and land dinosaurs were created on the 6th day of the creation week. This is documented in the only eye witness account of “In the beginning” Genesis 1:1, that we have. It is an account given by God through His Holy Spirit in the first book of the Bible, the book of Genesis.
 
What happens to us is that we get hung up on the word dinosaur, e.g. originally dinosauria or terrible lizard. The word dinosaur was created by a Bible believing scientist, the English paleontologist Richard Owen in 1842. The problem most people will face when looking into this subject is the evolutionary worldview and the hundreds of millions of years injected into the molecules to men Theory of Evolution. If a frog turns into a prince instantly, that’s a fairytale, but if a frog turns into a prince over millions of years, that evolution. So, evolution is really a fairytale for grown-ups.
 
I think we do a disservice to ourselves when we fail to recognize that our public school system, with regard to the biological sciences in particular, indoctrinates rather than educates our children. That is why we end up asking such questions. When you are told only one explanation, Darwinian evolution, and you allow no criticism of that one explanation, you are discouraging critical thinking in general and indoctrinating rather than educating students. When you allow nothing other than a purely naturalistic view of life, man, etc. you limit yourself to a worldview that excludes all other philosophical explanations. This is neither scientific nor is it valid.
 
Some of the greatest scientific men and women of the ages were Bible believing scientists. Does that invalidate them or make their discoveries any less important? Do we exclude Isaac Newton from the list of great men of science because He trusted Jesus Christ as His Lord and Savior and believed the Bible to the Word of God? That would be absurd. So why are modern professors of the sciences being denied tenure, loosing their jobs, being excluded from publishing in scientific journals, etc. on the basis of their faith in the God of the Bible and their distrust of evolutionary dogma?  I highly suggest you get a copy of Expelled, No Intelligence Allowed by Ben Stein.

Make no mistake about this. There are literally thousands of men and women worldwide with graduate degrees in the sciences who believe that the Bible is the Word of God. Some are young earth creationists, as we are at Creation Studies Institute and some differ concerning time frames, but there is complete agreement that God is the ultimate Intelligent Designer of the universe and the Bible is completely accurate because it describes life as we see it today, e.g. every living thing is genetically programmed by God to reproduce itself according to its own kind, Gen. 1;12,21, 25.  That is what we see in nature today and that is what the fossil record declares to be true in times past, e.g. every fossil appears abruptly in the fossil record, fully formed.
 
So the question concerning dinosaurs is easily explained. The Bible talks about dinosaurs being alive contemporaneously with man, land dinosaurs, Job 40:15-24 and marine dinosaurs, Job 41:1-34 (which also contains a reference to the mysterious fire-breathing dragons of old). There has been documentation by various tribes and peoples around the world of dinosaurs that they personally observed and even hunted, http://www.s8int.com/dinolit18.html
 
 or http://www.bearfabrique.org/Dinoglyphs/dinoglyphs.html
 
or this clear depiction of a stegosaur http://christianforums.com/showthread.php?t=6929525&page=13
 
So we have numerous sources to support the biblical account of creation as well as evidence from anthropology of dinosaurs being alive together with men, not separated by the hundreds of millions of years of alleged evolution.