in which region were their fossils discovered?
The Morrison Formation of Garden Park, north of Cañon City
Allosaurus
The bones were collected from the Morrison Formation of Garden Park, north of Cañon City. 
how many years ago did the allosaurus exist? 155 to 145 million years ago which period was that? The late Jurassic period describe this creature's physical features It was a typical large theropod, having a massive skull on a short neck, a long, slightly sloping tail and reduced forelimbs. was it a herbivore, carnivore or omnivore? Carnivore did it give birth to the young one or did it lay eggs? Lay eggs
wiki:1566137
Allosaurus [SEP] Early discoveries and research
The bones were collected from the Morrison Formation of Garden Park, north of Cañon City. Marsh and Edward Drinker Cope, who were in scientific competition with each other, went on to coin several other genera based on similarly sparse material that would later figure in the taxonomy of "Allosaurus". These include Marsh's "Creosaurus" and "Labrosaurus", and Cope's "Epanterias". In their haste, Cope and Marsh did not always follow up on their discoveries (or, more commonly, those made by their subordinates). For example, after the discovery by Benjamin Mudge of the type specimen of "Allosaurus" in Colorado, Marsh elected to concentrate work in Wyoming; when work resumed at Garden Park in 1883, M.