Many years ago I remember crossing it once, down in the upper Snowy valley, via the shortcut pad between Seamans Hut and Muellers Pass.
I have a small collection of books, maps etc for the region, possibly some older, rarer ones. When I get a chance I'll have a look for any references re the name.
Nothing on NSW Geo Names Board, only Rawson Pass, Alice Rawson Peak (official) and Mt Alice Rawson (variant).
But I did find this online, which may help form a view that it's named informally:
https://mulubinba.com.au/wp-content/uploads/2017/03/Summer-Walking-Guide-Rev-A-.pdfOn page 4 (end section of the Kunama Ruins track notes) it states:
Or for the fit and adventurous, an interesting and strenuous circuit can be done by climbing the steep slope to the S, across the saddle between Mts Northcote and Clarke, and dropping down in to the gully that joins Rawsons Creek.
And one of our own, NNW, makes a clear reference to it here:
https://www.bushwalk.com/forum/viewtopic.php?f=36&t=18178#p244121This person looks to be making a similar reference:
https://www.kev570.com/snowy31.jpgThe Snowy River running down from Mt Kosciuszko (left) and Rawson Creek running down from Mt Clarke (centre).