234 



SCIENCE. 



[Vol. VIII., No. 188 



or calcareous, — here, in its original condition; 

 there, oxidized and dried ; in another place, crystal- 

 lized and cleansed. Fortunately the Okens are not 

 all dead ; but their generalizations' are restrained by 

 a wise caution as to the genuineness of facts, and 

 regulated by measurements. Dr. Orton's report 

 proves this in a most satisfactory manner — if it 

 needed proof. 



The difference between the Pennsylvania and 

 north-west Ohio oil and gas regions is fourfold : 1°, one 

 is Devonian, the other Silurian ; 2°, one is sandstone, 

 the other limestone ; 3°, one is decidedly waved, the 

 other almost on a dead level ; 4° (and this is what 1 

 wish specially to discuss), the one is non-cavernous, 

 the other cavernous. 



Thirty years ago I began to insist upon the geologi- 

 cal (especially the topographical) importance of the 

 underground chemical and mechanical erosion of the 

 limestone formations of the world. I was led to 

 this by my first field-work in the Silurian valleys of 

 Pennsylvania and my early study of the blue-grass 

 country of Kentucky. I saw that the eastern and 

 western coal fields had been separated by the falling- 

 in of the roofs of myriads of mammoth caves in the 

 Trenton limestones, preceded by the same process at 

 the outcrops of the cavernous subcarboniferous lime- 

 stones. I have always opposed the notion of the 

 early age of the Cincinnati uplift. The nonconform- 

 ity in middle Ohio, and that around Nashville, are 

 important facts, but merely mark two out of many 

 local and temporary variations in the general down- 

 ward movement, which was otherwise uninterrupted 

 from Silurian times to the end of the coal-measure 

 age. It was not until then that the great upw^ard 

 and plicating movement took place, which started 

 the erosion of the United States area The principal 

 role in the erosion from that time until now has been 

 played by the limestone formations, under the solv- 

 ent action of drainage-waters acting everywhere 

 through them, down to and for some depth below 

 sea-level. Everybody knows the result in the great 

 Appalachian valleys. Everybody knows how the 

 Ohio valley region is undermined. I venture little 

 in asserting that the new oil and gas region of north- 

 western Ohio is thus undermined. This makes it 

 essentially characteristically different from the Penn- 

 sylvania, West Virginia, and eastern Ohio oil and 

 gas region. If the numerous wells bored at Findlay 

 and in the twenty-seven counties of north-western 

 Ohio have none of them struck through the roof of 

 a mammoth cave, that negative argument is of no 

 force when one calculates the chances of a well be- 

 ing drilled directly over such a cave. These caverns 

 are the great underground drainage-channels. They 

 correspond to the large streams on the earth's sur- 

 face. What would be the chances for and against a 

 man in a balloon at night dropping a bag of ballast 

 into a river ? A river, however, is a mile, half a 

 mile, a furlong wide ; a cavern cannot be more than 

 fifty or one hundred feet wide. On the other hand, 

 the caves are probably somewhat more numerous 

 than the large surface- streams, but not much. Cer- 

 tainly no one will venture to deny the undermined 

 condition of Ohio, until as many thousand wells have 

 been bored into the Trenton formation as have been 

 bored into the Pennsylvania Devonians. 



But the underground drainage is only collected 

 into and passed through the mammoth caves to some 

 exit. Its collection takes place through the infinite 

 multitude of vertical fissures which cut ud the whole 



limestone formation into blocks ; and these fissures 

 are all widened by chemical solution. The whole 

 Trenton underground of Ohio must be like the 

 Eoman arsenal works at Baix, — a sort of crypt, in 

 which water stands now at a level in the caves and 

 fissures, because it can find no rapid issue at sea- 

 level. In central Kentucky the cave-waters flow, 

 because they can issue in the bed of the Ohio River ; 

 but in north-western Ohio the top of the Trenton Dr. 

 Orton shows to lie from three hundred to nine hun- 

 dred feet below sea-level (i.e.. in round numbers, 

 from eight hundred and fifty feet to fourteen hun- 

 dred and fifty feet below the surface of Lake Erie), 

 and therefore no flow is possible. The water must 

 be standing water : the oil will therefore rise to its 

 surface, and the gas press upon the surface of the 

 oil, and over the whole extent of communicating fis- 

 sures and caves equally. 



But how could caves be formed at such a depth 

 beneath sea-level ? Standing water may corrode, 

 but cannot erode. No one dreams that our Silurian 

 caves in Pennsylvania follow the limestone strata 

 many thousands of feet beneath sea level under the 

 great synclinals. No ; but there are some wonder- 

 ful facts for all that. There is a stream in Brush 

 valley which sinks and flows under Nittany Moun- 

 tain to rise in Nittany valley, where it drives a large 

 mill. Sawdust and other things — a miller's hat 

 among them — have made the underground voyage. 

 The top of the limestone lies beneath the mountain 

 two thousand feet lower than its outcrop and one 

 thousand feet beneath ocean-level. It is an inverted 

 siphon, with one mouth several hundred feet higher 

 than the other ; the confining top wall of the siphon 

 being impervious Utica clay slate. At the Roman 

 baths near Zurich (Baden in Aargau) river- water 

 descends from a vertical outcrop to a depth of three 

 thousand feet, and ascends, mineralized and heated, 

 to the bath houses. The hot springs of Virginia are 

 similar deep inverted limestone siphons. 



In fact, there is no such thing as standing water 

 anywhere.' All water flows. Mere evaporation at 

 one end of a canal will cause a current to set from 

 the other end. Hydraulic pressure from the surface 

 of middle Ohio will suffice to produce a universal 

 lateral and upward water movement in northern 

 Ohio, the Trenton sinking in that direction. If the 

 currents thus induced be infinitely slow and gentle, 

 nevertheless there has been an infinite amount of 

 geological time (since the coal age) for them to effect 

 their underground erosion in. 



To all this must be added the great depth of the 

 real rock- basin of Lake Erie. It is now only two 

 hundred or three hundred feet deep ; but who knows 

 the thickness of its lining deposits ? It has been re- 

 ceiving the inflow of Michigan, Indiana, Ohio, Penn- 

 sylvania, and the Canada peninsula for an unknown 

 length of time, and, in addition to previous deposits, 

 the glacial drift and modern river-muds. My belief 

 is that its mother rock-bottom is excavated to a depth 

 greater than the deepest wells of the new oil and 

 gas region ; and, if so, then the origin of the system 

 of mammoth caves and fissures which hold the salt 

 water, oil, and gas of north-western Ohio is relieved 

 of difficulties. The water which is now nearly stag- 

 nant, flowed then freely to its natural outlets ; the 

 underground erosion which is now infinitesimally 

 feeble, proceeded then energetically, at a rapid rate 

 and on a grand scale. 



What I wish to draw attention to is this : granting 



