Because just after I posted, I remembered that one of Portmarnock's only routing changes was in 1908 to change two short par-4's at 6 and 7 in to a par-5 and a par-3...
So in 1900 it only had two one-shotters...
So your premise may be right that there were more courses at that time with only 2 par-3's... But the list would still be considerably shorter than those with 3 or more... The Haskell probably had something to do with this if true...
I agree it would be an interesting study
Ally,
According to the centenary book, Portmarnock had - in today's language - three one shotters in 1896. The 7th was 190 yards (it was 181 yds in 1909 and a bogey 3), the 12th at 125 yards (bogey 3) and the 17th at 170 yds (bogey 3).
The old 2nd hole which ran between today's 2nd and 3rd holes was 230 yards long, but would have probably been considered a bogey 4 at that time.
Note that Royal Dublin had only three holes under 200 yards in 1909 and the original OTM layout at RCD had only two holes under 200 yds in length in 1892.
TOC had only two holes between 200 and 300 yds in 1879, and the shortest was the 9th at 277 yds; the other was the 10th at 290 yds. Isn't it just accidental that TOC didn't possess holes in the 200-250 yds range that would become par threes today.
It's only natural that the number of "par threes" on courses increased, once it was decided that holes less than 250 yds would be classed as par threes, but for one reason or another, TOC had a "gap" of 100 yds in the hole ranges, and this gap just happened to lie on either side of the future cut-off point between par threes and par fours.