View of Rogue Valley from Wagner Butte

Geology of Ashland, Oregon by C. B. Watson




It would seem strange if, looking out toward the north, northwest and to the east from where we now live, at Ashland, no mountains were in view, but instead the broad Pacific ocean spread to the limits of vision, and a heavy surf beat the shore where the present northern, northeastern and eastern limits of our little city are. Yet the time was when that condition pre­vailed. Long before the Cascade mountains rose above the surface of the sea, when its waters washed the foot of the Rocky moun­tains, or some continent in that direction, nearly, or perhaps quite a thousand miles away, the Siskiyou mountains stood, an island in this vast waste of waters. It had volcanoes then that flashed their flames skyward; a beacon light to a shipless sea. The greater part of Europe was yet under the ocean, and the great sedimentary deposits that consitute the greater part of that continent, were being laid down far beneath the waves. The Blue mountains, three hundred miles to the northeast, were also an island and the nearest land in that direction, while the high Sierras, far to the south was its nearest neighbor. This island was very extensive and extended to the Sacramento valley on the south, comprising what is now called the Wooly Bully mountains, Scotts mountains and the Siskiyous. This cluster of mountains is termed by the U. S. Geological Department, "The Klamath Group," and is described as an old Cretaceous island. Ashland is sit­uated directly on the shore line and this shore is easliy traced for fifty miles each way. The records of its history are found in the sand stone that laps up on the foot of the island. Within the corporate limits of our city we have many pages of this history, easily read by the student of geology. The great sand stone cliffs in sight on the north side of Bear creek contain a story more strange and interesting than any fiction. Hardly a stone foundation in the city but has shells of fish and animals that were once denizens of the deep, and are long since extinct. Even near Siskiyou station, four thousand feet above sea level, are cliffs of sand stone filled with trigonia, trilobit, amonite, oyster and many other shells that never lived outside of the ocean. Many of them are long since extinct and only existed during that period known to geologists as the Cretaceous. During the time the monsters and leviathans of the deep, only known to us now by the remains that have been preserved in these sand stone deposits, played their pranks and fought their titanic battles where some of our lower streets are. The mastodon, mammoth and hairy elephant abounded in great numbers, for that was the period of abundant and gigantic forms of life. Standing on the summit of Ashland Butte then nothing but ocean could have been discerned within the limits of vision. A roaring surf rolled over the spot where Shasta now stands just off a splendid land locked harbor where Yreka is. All of the placer mines of northwestern Oregon, have been worked within this old island, or along its shore line. These placers have been fed from the great quartz veins within the island and have furnished millions of dollars in gold.
During the period of which we are treating, the coal beds that are now being exploited around the edges of this old island, including those at Coos Bay, were laid down and since that time from the effect of great pressure and heat have been forming coal. This informs us also that at that period heavy growths of vegetation grew around the shores; doubtless forests the like of which do not now exist. When boring for oil a few years ago, just across Bear creek, a depth of almost two thousand feet was reached, and yet the work stopped before they had passed through the shale which is a sedimentary formation and was deposited at a still earlier date. The top of the oil well is below the coal deposits that are being prospected near by. We therefore may reasonably conclude that the sedimentary deposit reaches a depth of, at least, two thousand feet below the coal beds. There is more than two thousand feet more above that of sediment, consis ting of shale, clay, conglemorate and sand stone, before we reach the capping of volcanic lava that was poured out from the top of Grizzly ridge which followed the elevation of the Cascade range above the sea.
There are three distinct beaches along the side of that mountain and within sight of Ashland. Two of these beaches were of the ocean and one seems to have been fresh water. We have then at least 4000 feet of sedimentary deposit just off the shore line which required a length of time beyond the powers of man to estimate by any oridnary method of reckoning time. The great sand stone cliffs that are picturesque sights of the mountain side north of town, stand on a bed of conglomerate that shows at least fifty feet in depth. Some of these boulders are large and some are small, but all are cemented together and have been rounded by stream action and not by beach action. East of Phoe­nix there are great tree trunks lying, end on, on top of this conglomerate and having two hundred feet of solid sand stone cliffs superimposed above them. That rocky tract of Rogue river valley known as "the desert," is made so by the disintegration of other cemented boulder cliffs, such as I have above described. The fact that these are stream washed suggests an investigation as to their source. Examination leaves almost a positive assur­ance that they are not of a formation either like the Cascades nor like that of the old island. The existence of an old river bed coursing southwesterly through central eastern Oregon, is easily traceable to near the foot of the Cascade mountains on the east side and there, apparently being cut off by the uplift of that range, together with other evidence that can not be given in the space of a single newspaper article, suggests it as the probable source of these great boulder beds, and that it had its mouth in a great delta where the Rogue River valley now is. If this be true, then there was a time long prior to the rise of the Cascade mountains, when at an earlier date the country between here and the Rocky mountains was above the water and formed a continent of large extent which was subsequently depressed below the ocean, only to be lifted again in the formation of the Cas­cade Barrier (which is the title given by Prof. Condon, in his charming book entitled "The Two Islands.") Prof. Condon does not however mention the "Old River Bed," which is well known to the stockmen in eastern Oregon. I have crossed this old river bed where it is 600 yards wide, south of Bear creek Buttes.
I have just touched upon some of the proofs but have said nothing of the subject from its utilitarian side. That it is a subject of great interest to the miner, the fruitgrower and the farmer, there is no doubt, and I hope in the near future to further develop the subject. The Great Marble Halls of Oregon, heretofore known as the Josephine County Caves' constitues another interesting chapter in its history. Of the Marble Halls, and other interesting features that pertain to this subject I cannot speak at this time. I expect to give a lecture, to be illustrated with stereoptican pictures, on Friday evening, Dec. 13th, at which time I hope to present this interesting subject fully. C. B. WATSON.