Answers

As Poul Anderson's "Wildcat" proceeds, conversations between the characters disclose quite a complicated time travel scenario:

they are drilling for oil in the Jurassic;

their employer is the Trans-temporal Oil Company, Transoco, although the US government has a strong say in proceedings;

there is a shortage of oil in the twentieth century because Transoco has taken so much of it from the past;

 

the existence of time travel is a state secret except to those who are involved in it;

 

men and equipment are transmitted through time by a projector that remains in the present;

 

an inertial effect decrees that time travelers spending a year in the past necessarily return to their period a year after their departure;

 

thus, the concept of simultaneity between past and present is applicable;

 

the minimum period of pastward transmission is a hundred million years whereas the future can be reached in hundred year hops;

Herries wants heavy weapons to use against dinosaurs but such weapons are needed back home where the international situation is critical.

What can this be leading to? Can time travel somehow be used to affect that international situation?

HG Wells' The Time Machine, written in the late nineteenth century before heavier than air flight, is dated by incomprehensible phrases like "'...plough you for the Little-go...'" "Wildcat" is dated by its Cold War scenario and by its use of the term "Negroes."