TITLES AKD ABSTRACTS OF PAPERS 155 



important eonstnu-tion projects might suggest. This was done during the 

 summers of 1917 and 1010, in close cooperation with (a) the several division 

 engineers of the department, whose experience with materials has afforded 

 many practical suggestions and problems for research, and (b) the testing 

 engineer of the State Highway Laboratory, who is studying the composition 

 and physical properties of several hundred samples of rock, gravel, till, sand, 

 and clay collected to represent types from all parts of the State. 



The object of this paper is to indicate some of the ways in which such a 

 survey, when combined with laboratory study, enables the highway engineer 

 to judge whether or not he may expect to find suitable material near the 

 project, and when several different kinds of material are available, how to 

 rhose among them. 



Presented without manuscript. 



CARBOXIFEROUS SALT AND POTASH DEPOSITS OF EASTERN CANADA 

 BY ALBERT O. HAYES 



(Abstract) 



stratified salt deposits of early Mississippiau (Windsor) age occur at 

 Malagast, Cumberland County, Nova Scotia. The salt occurs as stratified 

 sedimentary deposits, and was proved in 1018 by a shaft to lie at 85 feet depth, 

 and drilling operation indicated a thickness of several hundred feet. The 

 shaft and mine workings have already proved a commercial body of salt ; also 

 an interbanded zone of sylvite and other potash-bearing minerals which prom- 

 ise to be of commercial value. 



A revision of the geology of the Carboniferous system in. New Brunswick 

 indicates the Windsor horizon to underlie large areas hitherto supposed to 

 belong to an older series. 



Presented by title in the absence of the author. 



NATURAL GAS DECLINE CURVE 

 BY KO SWELL H. JOHNSON 



(Ahstract) 



The natural gas decline curves which have so far been published are decline 

 curves of pressure and have ordinarily been of single wells. In the mean- 

 while there have been published an extensive collection of oil-well decline 

 curves and there has been considerable speculation as to the formula of these 

 curves. It seems desirable, therefore, that a natural gas volume decline curve 

 should be published. p 



There are a number of difficulties that liave so far deterred the construc- 

 tion of these curves : 



1. Gas wells are never allowed to produce freely, and their decline curve, 

 therefore, is largely determined by the history of the back pressures to which 

 the wells liJive been subjected. 



