This form of the word is not very common but does see some use as the present participle/gerund of "to summit" as in "Upon summit(t)ing the mountain we took photos but had to begin our descent ...
Possible Duplicate: When is “L” doubled? I'm confused about the two spellings. In which contexts do I have to use canceling or cancelling? Google returns 15.6 million results ...
Some verbs can have double Ls in the gerund form; for example: modeling; modelling traveling; travelling Which form should we use, or which form is used more in the literature?