Can you supply a reference for the entire list and the details of the 40, or so, items removal?
Archeologist Dr. John Clark is responsible for the initial list, and is currently attempting to complete a comprehensive list, with the aide of others. Here is a video which describes the effort:
Most of these were once considered to be ridiculous claims of the Book of Mormon, but have since been proven plausible or true.
1) City societies in America.
2) Stone boxes in America.
3) Engraving on metal plates in the Middle East
4) Literate native Americans - could read and write
5) Large scale battles and warfare
6) Moats
7) Walls
8) Palisades
9) Slings
10) Swords
11) Clubs
12) Cotton armor
13) Detached arms as a trophy of battle
14) Fleeing to towers or pyramids in a failing battle
15) Human sacrifice
16) Canabalism
17) Temples
18) Towers
19) Palaces
20) Thrones
21) Cities of cement
22) Kings and Kings over Kings
23) Stone-carved histories
24) A king who also labors with his own hands
25) Record keeping with special attention to the Baktun (400 years) and Katun (20 years)
26) A population of millions of people
27) Military Costumes
28) Highways
29) Barley based monetary system
30) Scimitars or curved weapons
31) Greek names
32) An Arabian river flowing year-round into the Red Sea.
33) Animal sacrifice three days journey from the Jerusalem Temple.
34) Matching New World geography. With hundreds of references, this isn't as easy as it might seem.
35) Hebrew words spoken in Americas
This is as complete as I can get it, for the moment. Once considered anachronisms of the Book of Mormon, many of these are now anachronisms of the 1830's; they simply didn't exist in Joseph Smith's world, as pertaining to the American Indian. Anachronisms work both ways.