fuller] COLLECTION OF WELL RECORDS AND SAMPLES. 21 
PROPOSED SECTION OF OIL AND GAS (1902). 
The collection of records finally became so important that it was 
thought that a section, organized for the purpose of collecting them in 
connection with a study of the oil and gas fields, might be organized to 
advantage, and an outline plan for such a section was, at the request 
of Mr. M. R. Campbell, submitted to the geologist in charge of 
geology April 28, 1902, by the present writer. The following is an 
extract from this plan: 
In the prosecution of the work of areal mapping, and in the determination of the 
structure of the areas surveyed by Mr. [M. R.] Campbell and members of his party 
in Pennsylvania and Indiana, it has become apparent that great importance is to be 
attached to the information which may be derived from the deep borings for oil and 
gas. 
As has been pointed out by Mr. Campbell, it is generally only in increased details 
of outcrop, made possible by accurate topographic maps, and more especially in the 
greater refinement in structural details, that improvement has been made upon the 
detailed work of the earlier surveys in the region mentioned. Engineers, coal opera- 
tors, and oil and gas men with whom the geologists have come in contact and who 
have learned of the nature of the structural work which is now being undertaken, 
have almost invariably shown a marked interest in what is being accomplished and 
have fully appreciated its value to them as practical men. 
Already many errors, some of them very grave, have been found in the structural 
work of the Second Survey of Pennsylvania. Supposedly continuous folds have 
been found in reality to consist of a series of short disconnected ellipsoid domes and 
canoe-shaped troughs, and marked by frequent irregularities and by noticeable offsets 
at their terminations. Others have been shown to vary at angles as high as 60° or 
more from the positions previously determined, and, in fact, everywhere abound in 
unsuspected relations. The once famous oil fields west and northwest of Bradys 
Bend on the Allegheny River have previously been thought to have no relation to 
structure, but have now been proved to have a very close and definite relation to it, 
a fact that should be of great value in the drilling for the Speechley oil sand which 
is now going on, and in the drilling of gas wells, which, following the recent revival 
of activity, are fast becoming of great importance in this and other regions. 
The determination of the minor but important details of structure is dependent (1) 
upon information afforded by mines, (2) upon observation and correlation of natural 
outcrops, and (3) upon information afforded by deep wells. The first is available 
only in synclines containing workable coals. The second is of little value in many 
localities because of the general absence of distinctive characteristics over broad areas 
and through considerable vertical ranges of the Devonian and Carboniferous rocks, 
not only in Pennsylvania and Indiana, but in many other of the areas where these 
rocks occur. In such regions the oil and gas wells have frequently furnished the only 
reliable data for the determination of the structural details. 
The growing disposition on the part of the States to cooperate with the United 
States Geological Survey makes it somewhat probable that work similar to that 
now going on in Pennsylvania will at no very distant date be undertaken at other 
points, where presumably similar conditions will prevail and similar results be 
expected and required. 
The great value of well records in his work in Pennsylvania was fully appreciated 
by Mr. Campbell, and considerable amounts of time were devoted both by him and 
by myself to the collection of such records. Some 1,500 were obtained in 1901. 
It has become apparent, however, that to carry out the collection of records to the 
