The Cretaceous Dinosaur formations extend somewhat further out on the plains to the eastward, and the best collecting regions thus far explored are in eastern Wyoming, central Montana and in Alberta, Canada.
THE FIRST DISCOVERY OF DINOSAURS IN THE WEST.
_By Prof.S.W.

Williston._ Most great discoveries are due rather to a state of mind, if I may use such an expression, than to accident.

The discovery of the immense dinosaur deposits in the Rocky Mountains in March, 1877, may truthfully be called great, for nothing in paleontology has equalled it, and that it was made by three observers simultaneously can not be called purely an accident.

These discoverers were Mr.O.Lucas, then a school teacher, later clergyman; Professor Arthur Lakes, then a teacher in the School of Mines at Golden, Colorado; and Mr.William Reed, then a section foreman of the Union Pacific Railroad at Como, Wyoming, later the curator of paleontology of the University of Wyoming--even as I write this, comes the notice of his death,--the last.

I knew them all, and the last two were long intimate friends.
In the autumn of 1878 I wrote the following:[19] "The history of their discovery (the dinosaurs) is both interesting and remarkable.