Show CAMPFIRE CAMP FIRE CHATS by PAUL glimpses into the geological field the system of the west by paul the great mesozoic era closes with the great cretaceous system two distinct periods of submergence and an intermediate land epoch served to bring about three divisions viz the lower the middle and the upper cretaceous after the close of the jurassic large western submerged areas became land due to continental warping this occasioned the development of large lakes and basins wherein formations of non marine origin were deposited these continental deposits caused by the first and lesser submergence cover large areas on the coast in oregon washington new mexico etc northerly they are found along the front range extending into british columbia and alaska in places these formations sandstones etc rest conformably on rocks of jurassic age whereas at other localities they are found to rest on rocks of older age the middle cretaceous following the lower cretaceous period was essentially a land epoch this longtime gap between the series is represented by unconformities especially in the coast and in the gulf regions in places such a long gap of time exists between the lower and upper series that no species of fossils found in the one occur in the other As a whole the history of the great cretaceous system is very complex none of the preceding great systems presents such varying conditions locally as well as generally this is especially the case when speaking of the following upper cretaceous period there marine deposits alternate with fresh water and deposits numberless gradations take place and the correlation of the beds at different localities on or purely grounds presents enormous obstacles only who have given most of their time to the study of the system are qualified to unveil the existing complexities the upper cretaceous beds and the beds of transition between the latter and the early Teri tary are of the great economic importance they are the scour ces of our western coal mineral oil and natural gas deposits our great and successful oil and coal companies are realizing the aforementioned difficulties readily and their field work is done by competent geologists able and prepared to overcome such ob obstacles st acles mining geologist salt lake men who are able at least to point ami places where and i where i not out conditions fro from tt a and st structural ruc tural viewpoint view point no are favorable enough to invite system at prospecting such asp is however not the th case with most of the smaller companies the daily press contains from time to time articles wherein statements somewhat like hiir the following appear the oil company has at a great expense secured the services of mr N a well known pennsylvania oil expert to locate the oil poola pools on our oil lands mr N has been drilling for oil ever since he began to wear pants and is confident that he will locate a producing well for us this is generally the last the public hears about such enterprises as the operators are wise enough to keep their duster and their irish dividends for themselves competent ana honest aas eastern geologists were the first to realize the existing difficulties and will invariably refer their clients to one of the few western specialists it would lead too far to give a tion of the different def ferent strata or even series of strata beginning at the bottom following the mentioned unconformity come in succession ion the dakota sandstone the colorado series the montana series the laramie and finally the post laramie series denver livingston etc the exact bor derline between the upper cretaceous and the overlying lower tertiary eocene has not been conclusively established everywhere and is at the present the subject of investigation it would lead too far to mention the distribution of the cretaceous beds in the west they are found to cover large areas in all of our western states observations already made point to the fact that by the close of the laramie the development of mountains by folding was in progress and it is probable that most of the cordilleran region was elevated though perhaps not to its present height some ranges of the the uinta and wasatch mountains were up ridged great ageous activity tools to place at the close of the system outflows of lava occurred along the wasatch and great masses of intrusions bingham park city StarA St arRange Range central idaho henry mountains butte etc were thrust up amid the older strata 01 |