The Chest Register is a range of notes. Within that range of notes one can sing in Chest Voice which is to say that one is using the function of Complete Glottal Closure.
Wikipedia tells you that the use of “Chest Register” in vocal discussions is out of fashion these days. I will use it just like Garcia did, to indicate a range of notes. That “Chest Register” range, in which Garcia includes all vocal categories, is:
Remember that this all inclusive range of notes is not an indication of what everyone should be able to sing. That bottom of the well note that basses should be able to sing is well out of reach of most everyone else. Just as that top note that some tenors only dream about singing is not going to be something the bass will be able to reach.
The discussion of registers in Garcia’s writings is extremely confusing if one gets the terms mixed up. I believe this is the inspiration for the pedagogical world to want to ban “Chest Register” from the Authorized Politically Correct Dictionary of Technical Terms.
Garcia gives us his evidence that the “Chest Register” was already a general problem for the pedagogue of his day:
As we have said, the chest register is generally denied or rejected by teachers, not that one could not draw from its application an immense advantage, nor that the suppression of the range which it embraces would not deprive the singer of the most beautiful dramatic effects or the most favorable contrasts, but because one can approach the study of this register only with the help of profound knowledge, under the threat of ruining the student’s voice, and because the blending of this register with that of the falsetto can be secured only by a long and ably directed labor. It has therefore been judged simpler and more natural to free oneself from the difficulty of studying it.
A Complete Treatise on the Art of Singing: Part 1 page 50
