Another classic rebus (that is, old style rebus) puzzle. We just had one of these last week. I love this sort of thing, and Mr. Fogarty's example of it is very well done. He has chosen four song titles, all of them in the form [gerund] in the [noun], and reinterprets them as placing the gerund inside the noun. All four of the nouns are 4 letters long; even better, two of the answers' gerunds are six letters long because they're missing the G, while the other two are seven letters long with the G. Symmetry is maintained.
All four song titles are very well known, and represent the 1950s, 1960s, 1980s, and 2000s. I'm actually fond of all four, and would rank them as follows:
1. RASINGININ (Singin in the Rain)
2. WIBLOWINND (Blowin in the Wind)
3. DEROLLINGEP (Rolling in the Deep)
4. DADANCINGRK (Dancing in the Dark)
Your mileage may vary, of course, and I want to emphasize that the relative rankings do not imply that the lower ones are unappreciated.
The fill is pretty good overall. 11D: Where Venice is (LOSANGELES) was deceptive for a while. FOUNDMONEY is an odd phrase, although I see how it fits the clue "Change out of an old pair of pants?" I'm not sure I buy it as a real thing, but the clue is funny. 46A: How many try to capture Bigfoot (ONCAMERA) is very good, but ALOERTER was a tough get. Turns out he captured the gold medal for discus in four consecutive Olympics, from age 20 to 32, which explains why he is the only one ever to have done this.
The NE and SW 4x4 sections are completely isolated, which I don't like. On the other hand, both have an X in them, so that added interest.
1A: Mel who co-wrote "The Christmas Song" (TORME) gets a D+. The Velvet Fog's name is a well-worn piece of crosswordese, and is only redeemed here by a slightly more interesting clue. I entered it as my first answer in the grid, but I was not 100% convinced that it was correct, so the first answer that fit that description for me was 2D: '60s sitcom son (OPIE). Talk about two outdated answers! 1D: Hamlet's relative (TOWN) needed more crosses for me to figure out. Excellent clue.