A fast response from M.H. of Look Higher! cleared up the mystery of the Calvin Bible translation. It is an English translation of Calvin's Latin translation. It was conducted by the Calvin Translation Society from 1845 to 1855 while translating his commentaries.
An excerpt from the preface to the CTS edition of Calvin's commentary on Genesis helped explain what we have here:
"As it was possible that a doubt might exist whether the version of Scripture used by Calvin was his own, or whether he had borrowed it from some other source; it was thought worth the labor to investigate the true state of the case, by having recourse to the excellent Library of the British Museum. For this purpose the several versions which Calvin was most likely to have adopted, had he not made one for himself, were subjected to examination. It was not necessary to refer to any made by Romanists; and those made by Protestants into the Latin language, which there was any probability he should use, were but two. One by Sebastian Munster, printed at Basle with the Hebrew Text, in 1534, from which the version of Calvin varies considerably; the other by Leo Juda and other learned men, printed at Zurich in 1543, and afterwards reprinted by Robert Stephens in 1545 and 1557. The last of these editions was made use of in comparing the versions of Leo Juda and Calvin; and though there certainly are differences, yet they are so slight as to leave the impression that Calvin took that of Leo Juda as his basis, and only altered it as he saw occasion."
Examples of Juda's and Calvin's Latin are given as well. To read a bit more from the commentary, visit CCEL.ORG's page.