208 I. C. WHITE — THE MANNINGTON OIL FIELD. 



Engineers, Halifax meeting, 1885, and also in 7V/,' Petroleum Age for January, 1886. 

 As a general reply to these stricture.-: ami also to illustrate the theory more fully, 

 the writer prepareda paper for The Petroleum Age which was published in the March 

 number of that journal, along with a map of western Pennsylvania, on which were 

 located the principal anticlinal lines, and also the large gas wells. Since the article 

 in question contains several points of interest not hitherto given to the public, the 

 principal portion of it is here republished, without the map, which can lie procured 

 from The Petroleum Age by any reader who wishes it for reference : 



" Where the anticlinal lines are drawn full on that map they represent actual 

 observations of myself or others, but the dotted lines are projections of arches ob- 

 served only at a few points ; for instance, Mr. Ashburner states that the Sheffield 

 gas wells are on the crest of an anticline, and when the Martinsburg axis of Mr- 

 Chance is projected approximately parallel to the others it passes through the 

 Sheffield region ; hence the two are assumed to be identical, and the same principle 

 has been followed in making the other projections. 



"There are probably other flexures in the rocks which traverse the district in 

 question that, in the rapid survey made of some of the counties, were not detected 

 by the assistant geologists of the Pennsylvania survey. The writer pleads guilty 

 to some mistakes of this nature, as well as of getting one anticlinal confused with 

 another, in the case of the Fredericktown uplift. Tins mistake, which was cor- 

 rected by Mr. II. Martyn Chance, in report V, may possibly have been duplicated 

 by others of the assistants before they became expert at detecting minute changes 

 in dip or stratification. 



"An inspection of the accompanying map will reveal the fact that the main 

 northeast and southwest anticlinals are cut by another set at nearly right angles, 

 which have been termed cross-cut anticlinals. To Mr. Ashburner belongs the credit 

 of first calling the attention of geologists to this feature in the rock structure of 

 Pennsylvania, and the great Kinzua-Emporium cross-cut wave which he first traced 

 through Cameron, Elk and McKean counties is shown on the present map. 



"The surveys of the western counties of Pennsylvania were practically finished 

 before the publication of Mr. Ashburner's observations in the northern portion of 

 the state, and hence although similar phenomena were observed they were not 

 described in similar terms or referred to similar causes. Thus. Stevenson (as well 

 as Rogers long ago) recognized a great bulge in the Chestnut ridge uplift, near 

 I niontown, by which the Hamilton rocks are elevated to the summit of the moun- 

 tain, but the arch dying down both north and south, the Catskill rocks fail to reach 

 the surface where the axis crosses the gorge of Cheat river in the one direction, and 

 the Chemung- beds are completely buried at the ( lonemaugh gap in the other. 



" During the last two years the writer has given considerable thought to these 

 cross-cut axes, and the results show that a cross-cut anticlinal (presumably identical 

 with the one crossing Chestnut ridge near Uniontown) goes through the famous 

 Cannonsburg and Hickory gas regions in Washington county, while another par- 

 allel to it, and a few miles west, goes through the village of Pinhook,or Lone Pine^ 

 and also cuts the Mc< hiigan gas field. 



"Another of marked extent has recently been traced by the writer through the 

 Murraysville and Grapeville region of Westmoreland county, the greatest gas field 

 in the world, so far as present developments show. < rroups of wells also appear to 

 cluster along the grand arch that Mr. Ashburner has traced through northern 

 Pennsylvania. 



"Having observed the importance of these cross-cut arches in the location of gas 



