1951 House.
Older Service Drop/Attachment/Meter
Updated panel 100 amps.
Spliced SEC in panel. Looks to me like they spliced the older 60Amp SEC with 100 amps to accommodate the main breaker.
I am calling it out a 60 amps and deferring to an qualified electrical contractor.
The only wire I could see was the grounded conductor at the service point.
What do you say!!