MYSTERY SOLVED!! The other day I signed up (for other reasons) for access on a Newspaper website to view old newspaper articles. This afternoon I thought I might solve this mystery by searching for articles on Martin & Schwartz. And I found the answer. Here are the articles that I found:
1) A 1939 article saying Sunoco purchased all the capital stock of M&S
2) A 1944 article stating that M&S is owned by Sunoco and Socony Vacuum (Mobil).
3) A 1947 article stating that M&S is owned by 4 owners - Sunoco, Conoco, Mobil and Standard Indiana.
That explains perfectly what I am seeing. It explains why Conoco and Standard Indiana didn't use the M&S 70 - because they DIDN'T own the company at that time. It also explains why Sunoco and Mobil did use the M&S 70 - they DID own the company. Apparently, Conoco and Standard Indiana came to the party later (between 1944 and 1947), just in time for the new M&S 80 pump....which all four owners used extensively.
The bottom line is that Conoco DID NOT own a share of Martin & Schwartz in 1937, as widely reported (even in the Wayne history book).
It all makes sense now.....
Andy