On page 57 it says the 'valuable' coin is the 1970s small date. However it shows on page 56 the 1970s large date being more valuable? Is this s misprint?
In the 3rd edition I found in PDF format a while back. The 1970S small and large dates are referenced on page 55. I see no written reference of large date being the one with added value. Only the small date.
That said there is an image on that page that seems to be a large date. The notes under it describes what to look for on a small date. Note it doesn't make reference to the image being one or the other, but thought that might confuse some people starting out.
Is it possible to have a 1970 small date with no mint mark?
A few scenarios come to mind that potentially could happen and make a missing mint mark. Note: I don't recall seeing any of these scenarios first hand.
1. Device (MM) on the die could be filled with grease.
2. Mint mark removed from coin after strike ( PSD
3. Polished off the die.
Adding to what others have already mentioned. The small date upper curl on the 9 points towards the center of the 7.
On the large date it points towards the tail end or bottom of the 7. I think it was mentioned above it points to the MM, but MM's move around some and may or may not be inline with the upper curl of the 9.
Circulation can alter appearances so you need to take everything into account. Thanks, Doug.
edit: to add/change "edition" above.
Second opinions are always recommended. Rookies thoughts!
Backup data often or good luck with the recovery process..... SME advice!