Free End of an Era by Robert J. Sawyer

but there are other creatures about, tiny mammals, that are even more closely related to us. But you — I’ve studied the history of life since it began. I don’t know of anything similar to you."
    "Its body is completely soft," said Klicks. "Creatures like that might go undetected in the fossil record."
    I turned to him. "But intelligent life arising millions of years before the first human? It’s incredible. It’s almost as if—"
    I’d like to claim that I was about to state the correct conclusion, that at that instant I had pieced together the puzzle and had realized what was going on. But my next words were drowned out by a great roaring clap, like thunder, followed by several bellowing dinosaur calls and the cries of flying things startled into flight. I recognized the noise, for my home was due south of Pearson International Airport and, despite the complaints from me and my neighbors, it had become part of the background of our day-to-day lives ever since Transport Canada had approved inland supersonic flights of the Orient Express jetliners. High overhead, three tawny spheres moving at perhaps Mach 2 or 3 streaked across the sky. At the least, they were aircraft, but I knew in an instant that they were much more than that.
    Spaceships.
    "You under a misapprehension operate," said Diamond-snout once the sky had stopped rumbling. "We are not from this planet."
    Klicks was flabbergasted, which pleased me no end. "Then where?" I said.
    "From — home world. Name I not find in your memories. It’s—"
    "Is it in this solar system?" I asked.
    "Yess."
    "Mercury?"
    "Quicksilver? No."
    "Venus?"
    "No."
    "Not Earth. Mars?"
    "Mars — ah, Mars! Fourth from sun. Yess. Mars is home."
    "Martians!" said Klicks. "Actual fucking Martians. Who’d believe it?"
    Diamond-snout fixed Klicks with a steady gaze. "I would," it said, absolutely deadpan.

Boundary Layer
    I can be expected to look for truth but not to find it.
    —Denis Diderot, French philosopher (1713-1784)
    The traveler’s diary — the one that purported to tell the story of a trip back to the end of the Mesozoic Era — had to be a fake, of course. It had to be. Oh, it superficially resembled my writing style. In fact, whoever had put it together had obviously read my book
Dragons of the North: The Dinosaurs of Canada
. In preparing the manuscript for that book, I got sick of all the italics. See, Linnaeus established that biological naming would be in Latin, and non-English words are usually italicized in modern typesetting. Plus, Linnaeus said the genus part of the name should always be capitalized: Tyrannosaurus rex. Since there are no common English names for individual types of dinosaurs, popular books on the subject have slavishly followed this convention so that almost every tenth word is italicized or capitalized, bullying the reader’s eye.
    I’d taken some flak from my colleagues for it, but in
Dragons of the North
I chucked out that convention. The first time I mentioned some Mesozoic critter, I’d use the Linnaean standard, but thereafter I’d treated the name as if it were a common English term, just like "cat" or "dog," uncapitalized and unitalicized. Well, whoever had cobbled together this bogus diary had copied at least that much of my style.
    Although I never used it, my palmtop had come bundled with a grammar-checking program. I had my diary from last year still stored on the Toshiba’s built-in optical wafer, so I called that up alongside the fake traveler’s diary. With each document in a separate window, I let the grammar checker run a stylistic comparison between them. The program produced a dozen charts — including "Flesch-Kincaid grade level," "average number of words per sentence," and "average number of sentences per paragraph." The conclusion was inescapable: both diaries, mine and the supposed time traveler’s, were in almost identical styles.
    The grammar checker had a feature that I’d never before found a use for: the ability