We know that <PERSON> and <PERSON> encounter the bodies of the Old Ones killed by a shoggoth, and then witness the shoggoth itself and flee the city afterwards. Then, having escaped the city and taken off in their aircraft, <PERSON> sees, or thinks he does, something. It seems that even <PERSON> himself was not completely satisfied or certain about this something though. In a letter to <PERSON> on 16 May 1931, he wrote:
"Now as to the end of the thing -- of course I'm not satisfied myself, but I am very oddly unable whether more or less definiteness is needed. Remember <PERSON>. In my tale the shoggoth provides a concrete & tangible climax -- & what I wished to add was merely a vague hint of further spiritual horrors -- as <PERSON> hinted with his white birds screaming "Tekeli-li! Tekeli-li!" I wanted to leave the actuality of the glimpse very unsettled, so that it might easily pass off as an hallucination. 417
Possibly I ought to have left it vaguer still -- & then again I had an idea that the thing ought to be developed at full length -- perhaps as a sequel to the present thing, or perhaps as an expansion of that thing to full book length .... with the Simon & Schuster request, received last January, in mind. What the thing was supposed to be, of course, was a region containing vestiges of some utterly primal cosmic force or process ruling or occupying the earth (among other planets) even before its solidification, & upheaved from the sea-bottom when the great Antarctic land mass arose. Lack of interest in the world beyond the inner mountains would account of its non-reconquest of the sphere. But then again, there may have been no such thing! Those Others may well have had their superstitions -- & of course <PERSON> was strangely read, nervously organised, & fresh from a terrific shock.... Anyhow, what I did set down was a sort of weak compromise betwist the two ways I vaguely & ineffectively thought it ought to be."
A shame that <PERSON> never wrote the sequel he refers to in the quotation above! 417