The phrase "a long excursion" is correct and usable in written English.
It can be used to describe an extended journey or trip, often for leisure or exploration purposes.
Example: "We decided to take a long excursion into the mountains to enjoy the beautiful scenery and fresh air."
Alternatives: "an extended trip" or "a lengthy journey."
One Memorial Day, on a long excursion, I visited the viewing deck at the DuPont Nature Center, overlooking Mispillion Harbor.
Our driver decided on his own that a visit to Ciudad Bolivar meant a long excursion around the capital, with a glimpse of the slums from several miles off.
Another was the state's refusal to defend Proposition 8, resulting in a long excursion into the procedural thicket on the question of whether supporters of the proposition have standing to carry on the appeal in the state's place.
But the band came back focused and fully aligned for the second set, particularly in a long excursion through "Harry Hood": winding its way from reggae to rock to limpid, floating abstractions and then down to earth.
Hitchens took me on a long excursion through his political life, an account of the Education of Christopher Hitchens, with key stops at the fatwa on Salman Rushdie, which had pitted everything he loved against everything he hated, and the first Gulf War in 1991, which he had opposed.
Nevertheless, in a long excursion into historical reconstruction, Justice Anthony Kennedy discovers that states' "sovereign immunity" from lawsuits in their own courts brought by anyone but the federal government has been an enduring principle of American law from before the constitution, which its authors assumed would be respected and therefore failed to mention.
Measurements also reveal that the process exhibits excitability: a relatively small change or perturbation causes the potential to undergo a large and long excursion before it returns to its steady-state value.
By turns comic and poetic, the book delivers the pleasures of a long, meandering excursion, in which the act of observing is its own reward.
I visited Beaufort on a brilliantly hot day this summer, and the only people around were a handful of Hezbollah fighters, a group of Beirutis on a day-long excursion through the South, and two Iranian tourists, with cheap cameras hanging from their necks.
Voyager owed its existence as well to luck — a once-every-176-year alignment of the outer planets that made it feasible for a single spacecraft to visit them all on one long excursion through the icy darkness, using the gravity of one planet to slingshot itself to the next, a technique conceived in 1961 by a U.C.L.A. graduate student.
The department was taking faculty and students on a day-long excursion to visit the villages, churches and countryside of Norfolk and Suffolk.
