B-20 Preliminary Notes on the Revision of the Geological Map of Eastern Colorado B-20 Preliminary Notes on the Revision of the Geological Map of Eastern Colorado
B-19 The Cretaceous Formations of the Northeastern Colorado Plains and the Foothills Formations of North-Central Colorado B-19 The Cretaceous Formations of the Northeastern Colorado Plains and the Foothills Formations of North-Central Colorado
B-13 Geology and Ore Deposits of the Platoro-Summitville Mining District B-13 Geology and Ore Deposits of the Platoro-Summitville Mining District
B-10 Geology and Ore Deposits of the Gold Brick District B-10 Geology and Ore Deposits of the Gold Brick District, Colorado